Как пишется формат файла

From Wikipedia, the free encyclopedia

This is a list of file formats used by computers, organized by type. Filename extension it is usually noted in parentheses if they differ from the file format name or abbreviation. Many operating systems do not limit filenames to one extension shorter than 4 characters, as was common with some operating systems that supported the File Allocation Table (FAT) file system. Examples of operating systems that do not impose this limit include Unix-like systems, and Microsoft Windows NT, 95-98, and ME which have no three character limit on extensions for 32-bit or 64-bit applications on file systems other than pre-Windows 95 and Windows NT 3.5 versions of the FAT file system. Some filenames are given extensions longer than three characters. While MS-DOS and NT always treat the suffix after the last period in a file’s name as its extension, in UNIX-like systems, the final period does not necessarily mean that the text after the last period is the file’s extension.^[1]

Some file formats, such as .txt or .text, may be listed multiple times.

Archive and compressed[edit]

• .?Q? – files that are compressed, often by the SQ program.
• 7z – 7z: 7-Zip compressed file
• A – An external file extension for C/C++
• AAC – Advanced Audio Coding
• ace – ace: ACE compressed file
• ALZ – ALZip compressed file
• APK – Android package: Applications installable on Android; package format of the Alpine Linux distribution
• APPX – Microsoft Application Package (.appx)
• AT3 – Sony’s UMD data compression
• ARC – ARC: pre-Zip data compression
• ARC – Nintendo U8 Archive (mostly Yaz0 compressed)
• ARJ – ARJ compressed file
• ASS, SSA –ASS (also SSA): a subtitles file created by Aegisub, a video typesetting application (also a Halo game engine file)
• B – (B file) Similar to .a, but less compressed.
• BA – BA: Scifer Archive (.ba), Scifer External Archive Type
• BIN – compressed archive, can be read and used by CD-ROMs and Java, extractable by 7-zip and WINRAR
• .bkf – Microsoft backup created by NTBackup.c
• Blend – An external 3D file format used by the animation software, Blender.
• .bz2 – bzip2
• BMP – Bitmap Image – You can create one by right-clicking the home screen, next, click new, then, click Bitmap Image
• cab – A cabinet (.cab) file is a library of compressed files stored as one file. Cabinet files are used to organize installation files that are copied to the user’s system.^[2]
• c4 – JEDMICS image files, a DOD system
• cals – JEDMICS image files, a DOD system
• xaml – Used in programs like Visual Studio to create exe files.
• CPT, SEA – Compact Pro (Macintosh)
• DAA – DAA: Closed-format, Windows-only compressed disk image
• deb – deb: Debian install package
• DMG – an Apple compressed/encrypted format
• DDZ – a file which can only be used by the «daydreamer engine» created by «fever-dreamer», a program similar to RAGS, it’s mainly used to make somewhat short games.
• DN – Adobe Dimension CC file format
• DNG – «Digital Negative» a type of raw image file format used in digital photography.
• DPE – Package of AVE documents made with Aquafadas digital publishing tools.
• .egg – Alzip Egg Edition compressed file
• .egt – EGT Universal Document also used to create compressed cabinet files replaces .ecab
• .ECAB, .ezip – EGT Compressed Folder used in advanced systems to compress entire system folders, replaced by EGT Universal Document
• ESD – ESD: Electronic Software Distribution, a compressed and encrypted WIM File
• .ess – EGT SmartSense File, detects files compressed using the EGT compression system.
• .exe – Windows application
• .flipchart – Used in Promethean ActivInspire Flipchart Software.
• .gbs, .ggp, .gsc – GBS OtterUI binary scene file
• .gho, .ghs – GHO Norton Ghost
• .gif – GIF Graphics Interchange Format
• .gz – gzip Compressed file
• .html – HTML code file
• .ipg – Format in which Apple Inc. packages their iPod games. can be extracted through Winrar
• jar – jar ZIP file with manifest for use with Java applications.
• JPG – Joints Photographic Experts Group – Image File
• JPEG – Joints Photographic Experts Group – Image File
• .Lawrence – LBR Lawrence Compiler Type file
• LBR – LBR Library file
• LQR – LQR LBR Library file compressed by the SQ program.
• .lzh – LHA Lempel, Ziv, Huffman
• .lz – lzip Compressed file
• .lzo – lzo
• lzma – lzma Lempel–Ziv–Markov chain algorithm compressed file
• LZX – LZX
• .lua — Lua
• .mbw – MBRWizard archive
• MHTML – Mime HTML (Hyper-Text Markup Language) code file
• .midi — Musical Instrument Digital Interface
• .mpq – MPQ Archives Used by Blizzard Entertainment
• .bin – BIN MacBinary
• .nl2pkg – NoLimits 2 Package
• .nth – NTH: Nokia Theme Used by Nokia Series 40 Cellphones
• .oar – OAR: OAR archive
• OSG – Compressed osu! live gameplay archive (optimized for spectating)
• OSK – Compressed osu! skin archive
• OSR – Compressed osu! replay archive
• OSZ – Compressed osu! beatmap archive
• PAK – Enhanced type of .ARC archive
• .par, .par2 – PAR Parchive
• .paf – PAF Portable Application File
• .pea – PEA PeaZip archive file
• PNG – Portable Network Graphic Image File
• Webp — Raster image format developed by Google for web graphics
• .php – PHP code file
• .pyk – PYK Compressed file
• .pk3 – PK3 Quake 3 archive (See note on Doom³)
• .pk4 – PK4 Doom³ archive (Opens similarly to a zip archive.)
• .pxz – PXZ A compressed layered image file used for the image editing website, pixlr.com .
• py, pyw – Python code file
• .rar – RAR Rar Archive, for multiple file archive (rar to .r01-.r99 to s01 and so on)
• RAG, RAGS – Game file, a game playable in the RAGS game-engine, a free program which both allows people to create games, and play games, games created have the format «RAG game file»
• RaX – Archive file created by RaX
• RBXL – Roblox Studio place file (XML, binary)
• RBXLX – Roblox Studio place file (exclusively XML)
• RBXM – Roblox Studio model file (XML, binary)
• RBXMX – Roblox Studio model file (exclusively XML)
• RPM – Red Hat package/installer for Fedora, RHEL, and similar systems.
• sb – Scratch file
• sb2 – Scratch 2.0 file
• sb3 – Scratch 3.0 file
• SEN – Scifer Archive (.sen) – Scifer Internal Archive Type
• .sitx – SIT StuffIt (Macintosh)
• SIS, SISX – SIS/SISX: Symbian Application Package
• SKB – Google SketchUp backup File
• .sq – SQ: Squish Compressed Archive
• .srt — SubRip Subtitle — file format for closed captioning or subtitles.
• SWM – Splitted WIM File, usually found on OEM Recovery Partition to store preinstalled Windows image, and to make Recovery backup (to USB Drive) easier (due to FAT32 limitations)
• SZS – Nintendo Yaz0 Compressed Archive
• TAR – TAR: group of files, packaged as one file
• Gzip, .tar.gz – (Gzip, .tar.gz): TGZ gzipped tar file
• .tb – TB Tabbery Virtual Desktop Tab file
• .tib – TIB Acronis True Image backup
• UHA – Ultra High Archive Compression
• .uue – UUE unified utility engine – the generic and default format for all things UUe-related.
• uf2 microsoft makecode arcade game.
• VIV – Archive format used to compress data for several video games, including Need For Speed: High Stakes.
• VOL – video game data package.
• VSA – Altiris Virtual Software Archive
• WAX – Wavexpress – A ZIP alternative optimized for packages containing video, allowing multiple packaged files to be all-or-none delivered with near-instantaneous unpacking via NTFS file system manipulation.
• .wfp a Wondershare Flimora project file
• WIM – WIM A compressed disk image for installing Windows Vista or higher, Windows Fundamentals for Legacy PC, or restoring a system image made from Backup and Restore (Windows Vista/7)
• XAP – Windows Phone Application Package
• xz – xz compressed files, based on LZMA/LZMA2 algorithm
• Z – Unix compress file
• zoo – zoo: based on LZW
• zip – zip: popular compression format
• ZIM – ZIM: an open file format that stores wiki content for offline usage

Physical recordable media archiving[edit]

• ISO – Generic format for most optical media, including CD-ROM, DVD-ROM, Blu-ray, HD DVD and UMD.
• NRG – Proprietary optical media archive format used by Nero applications.
• IMG – Raw disk image, for archiving DOS formatted floppy disks, hard drives, and larger optical media.
• ADF – for archiving Amiga floppy disks
• ADZ – The GZip-compressed version of ADF.
• DMS – a disk-archiving system native to the Amiga.
• DSK – For archiving floppy disks from a number of other platforms, including the ZX Spectrum and Amstrad CPC.
• D64 – An archive of a Commodore 64 floppy disk.
• SDI – used for archiving and providing «virtual disk» functionality.
• MDS – Daemon Tools native disc image format used for making images from optical CD-ROM, DVD-ROM, HD DVD or Blu-ray. It comes together with MDF file and can be mounted with DAEMON Tools.
• MDX – Daemon Tools format that allows getting one MDX disc image file instead of two (MDF and MDS).
• DMG – Macintosh disk image files
• CDI – DiscJuggler image file
• CUE – CDRWrite CUE image file
• CIF – Easy CD Creator .cif format
• C2D – Roxio-WinOnCD .c2d format
• DAA – PowerISO .daa format
• B6T – BlindWrite 6 image file
• B5T – BlindWrite 5 image file
• BWT – BlindWrite 4 image file
• FFPPKG – FreeFire Profile Export Package

LemonOS/LemonTabOS/LemonRoid[edit]

• LEMONAPP – LemonOS/LemonTabOS/LemonRoid App (.lem_app)

Other Extensions[edit]

• HTML – Hypertext Markup Language
• Msi – Windows installation file
• Vdhx – Virtual disk created by Hyper-V (Hyper-V runs on windows operating system)

Computer-aided design[edit]

Computer-aided is a prefix for several categories of tools (e.g., design, manufacture, engineering) which assist professionals in their respective fields (e.g., machining, architecture, schematics).

Computer-aided design (CAD)[edit]

Computer-aided design (CAD) software assists engineers, architects and other design professionals in project design.

• 3DXML – Dassault Systemes graphic representation
• 3MF – Microsoft 3D Manufacturing Format^[3]
• ACP – VA Software VA – Virtual Architecture CAD file
• AMF – Additive Manufacturing File Format
• AEC – DataCAD drawing format^[4]
• AR – Ashlar-Vellum Argon – 3D Modeling
• ART – ArtCAM model
• ASC – BRL-CAD Geometry File (old ASCII format)
• ASM – Solidedge Assembly, Pro/ENGINEER Assembly
• BIN, BIM – Data Design System DDS-CAD
• BREP – Open CASCADE 3D model (shape)
• C3D – C3D Toolkit File Format
• C3P – Construct3 Files
• CCC – CopyCAD Curves
• CCM – CopyCAD Model
• CCS – CopyCAD Session
• CAD – CadStd
• CATDrawing – CATIA V5 Drawing document
• CATPart – CATIA V5 Part document
• CATProduct – CATIA V5 Assembly document
• CATProcess – CATIA V5 Manufacturing document
• cgr – CATIA V5 graphic representation file
• ckd – KeyCreator CAD Modeling
• ckt – KeyCreator CAD Modeling
• CO – Ashlar-Vellum Cobalt – parametric drafting and 3D modeling
• DRW – Caddie Early version of Caddie drawing – Prior to Caddie changing to DWG
• DFT – Solidedge Draft
• DGN – MicroStation design file
• DGK – Delcam Geometry
• DMT – Delcam Machining Triangles
• DXF – ASCII Drawing Interchange file format, AutoCAD
• DWB – VariCAD drawing file
• DWF – Autodesk’s Web Design Format; AutoCAD & Revit can publish to this format; similar in concept to PDF files; Autodesk Design Review is the reader
• DWG – Popular file format for Computer Aided Drafting applications, notably AutoCAD, Open Design Alliance applications, and Autodesk Inventor Drawing files
• EASM – SolidWorks eDrawings assembly file
• EDRW – eDrawings drawing file
• EMB – Wilcom ES Designer Embroidery CAD file
• EPRT – eDrawings part file
• EscPcb – «esCAD pcb» data file by Electro-System (Japan)
• EscSch – «esCAD sch» data file by Electro-System (Japan)
• ESW – AGTEK format
• EXCELLON – Excellon file
• EXP – Drawing Express format
• F3D – Autodesk Fusion 360 archive file^[5]
• FCStd – Native file format of FreeCAD CAD/CAM package
• FM – FeatureCAM Part File
• FMZ – FormZ Project file
• G – BRL-CAD Geometry File
• GBR – Gerber file
• GLM – KernelCAD model
• GRB – T-FLEX CAD File
• GRI – AppliCad GRIM-In file in readable text form for importing roof and wall cladding job data generated by business management and accounting systems into the modelling/estimating program
• GRO – AppliCad GRIM-Out file in readable text form for exporting roof and wall cladding data job material and labour costing data, material lists generated by the modelling/estimating program to business management and accounting systems
• IAM – Autodesk Inventor Assembly file
• ICD – IronCAD 2D CAD file
• IDW – Autodesk Inventor Drawing file
• IFC – buildingSMART for sharing AEC and FM data
• IGES – Initial Graphics Exchange Specification
• .dgn, .cel – Intergraph Standard File Formats Intergraph
• IO – Stud.io 3d model
• IPN – Autodesk Inventor Presentation file
• IPT – Autodesk Inventor Part file
• JT – Jupiter Tesselation
• MCD – Monu-CAD (Monument/Headstone Drawing file)
• MDG – Model of Digital Geometric Kernel
• model – CATIA V4 part document
• OCD – Orienteering Computer Aided Design (OCAD) file
• PAR – Solidedge Part
• PIPE – PIPE-FLO Professional Piping system design file
• PLN – ArchiCad project
• PRT – NX (recently known as Unigraphics), Pro/ENGINEER Part, CADKEY Part
• PSM – Solidedge Sheet
• PSMODEL – PowerSHAPE Model
• PWI – PowerINSPECT File
• PYT – Pythagoras File
• SKP – SketchUp Model
• RLF – ArtCAM Relief
• RVM – AVEVA PDMS 3D Review model
• RVT – Autodesk Revit project files
• RFA – Autodesk Revit family files
• RXF – AppliCad annotated 3D roof and wall geometry data in readable text form used to exchange 3D model geometry with other systems such as truss design software
• S12 – Spirit file, by Softtech
• SCAD – OpenSCAD 3D part model
• SCDOC – SpaceClaim 3D Part/Assembly
• SLDASM – SolidWorks Assembly drawing
• SLDDRW – SolidWorks 2D drawing
• SLDPRT – SolidWorks 3D part model
• dotXSI – For Softimage
• STEP – Standard for the Exchange of Product model data
• STL – Stereo Lithographic data format used by various CAD systems and stereo lithographic printing machines.
• STD – Power Vision Plus – Electricity Meter Data (Circutor)
• TCT – TurboCAD drawing template
• TCW – TurboCAD for Windows 2D and 3D drawing
• UNV – I-DEAS I-DEAS (Integrated Design and Engineering Analysis Software)
• VC6 – Ashlar-Vellum Graphite – 2D and 3D drafting
• VLM – Ashlar-Vellum Vellum, Vellum 2D, Vellum Draft, Vellum 3D, DrawingBoard
• VS – Ashlar-Vellum Vellum Solids
• WRL – Similar to STL, but includes color. Used by various CAD systems and 3D printing rapid prototyping machines. Also used for VRML models on the web.
• X_B – Parasolids binary format
• X_T – Parasolids
• XE – Ashlar-Vellum Xenon – for associative 3D modeling
• ZOFZPROJ – ZofzPCB 3D PCB model, containing mesh, netlist and BOM

Electronic design automation (EDA)[edit]

Electronic design automation (EDA), or electronic computer-aided design (ECAD), is specific to the field of electrical engineering.

• BRD – Board file for EAGLE Layout Editor, a commercial PCB design tool
• BSDL – Description language for testing through JTAG
• CDL – Transistor-level netlist format for IC design
• CPF – Power-domain specification in system-on-a-chip (SoC) implementation (see also UPF)
• DEF – Gate-level layout
• DSPF – Detailed Standard Parasitic Format, Analog-level parasitics of interconnections in IC design
• EDIF – Vendor neutral gate-level netlist format
• FSDB – Analog waveform format (see also Waveform viewer)
• GDSII – Format for PCB and layout of integrated circuits
• HEX – ASCII-coded binary format for memory dumps
• LEF – Library Exchange Format, physical abstract of cells for IC design
• LIB – Library modeling (function, timing) format
• MS12 – NI Multisim file
• OASIS – Open Artwork System Interchange Standard
• OpenAccess – Design database format with APIs
• PSF – Cadence proprietary format to store simulation results/waveforms (2GB limit)
• PSFXL – Cadence proprietary format to store simulation results/waveforms
• SDC – Synopsys Design Constraints, format for synthesis constraints
• SDF – Standard for gate-level timings
• SPEF – Standard format for parasitics of interconnections in IC design
• SPI, CIR – SPICE Netlist, device-level netlist and commands for simulation
• SREC, S19 – S-record, ASCII-coded format for memory dumps
• SST2 – Cadence proprietary format to store mixed-signal simulation results/waveforms
• STIL – Standard Test Interface Language, IEEE1450-1999 standard for Test Patterns for IC
• SV – SystemVerilog source file
• S*P – Touchstone/EEsof Scattering parameter data file – multi-port blackbox performance, measurement or simulated
• TLF – Contains timing and logical information about a collection of cells (circuit elements)
• UPF – Standard for Power-domain specification in SoC implementation
• V – Verilog source file
• VCD – Standard format for digital simulation waveform
• VHD, VHDL – VHDL source file
• WGL – Waveform Generation Language, format for Test Patterns for IC

Test technology[edit]

Files output from Automatic Test Equipment or post-processed from such.

• Standard Test Data Format

Database[edit]

• 4DB – 4D database Structure file
• 4DD – 4D database Data file
• 4DIndy – 4D database Structure Index file
• 4DIndx – 4D database Data Index file
• 4DR – 4D database Data resource file (in old 4D versions)
• ACCDB – Microsoft Database (Microsoft Office Access 2007 and later)
• ACCDE – Compiled Microsoft Database (Microsoft Office Access 2007 and later)
• ADT – Sybase Advantage Database Server (ADS)
• APR – Lotus Approach data entry & reports
• BOX – Lotus Notes Post Office mail routing database
• CHML – Krasbit Technologies Encrypted database file for 1 click integration between contact management software and the chameleon(tm) line of imaging workflow solutions
• DAF – Digital Anchor data file
• DAT – DOS Basic
• DAT – Intersystems Caché database file
• DB – Paradox
• DB – SQLite
• DBF – db/dbase II,III,IV and V, Clipper, Harbour/xHarbour, Fox/FoxPro, Oracle
• DTA – Sage Sterling database file
• EGT – EGT Universal Document, used to compress sql databases to smaller files, may contain original EGT database style.
• ESS – EGT SmartSense is a database of files and its compression style. Specific to EGT SmartSense
• EAP – Enterprise Architect Project
• FDB – Firebird Databases
• FDB – Navision database file
• FP, FP3, FP5, FP7 – FileMaker Pro
• FRM – MySQL table definition
• GDB – Borland InterBase Databases
• GTABLE – Google Drive Fusion Table
• KEXI – Kexi database file (SQLite-based)
• KEXIC – shortcut to a database connection for a Kexi databases on a server
• KEXIS – shortcut to a Kexi database
• LDB – Temporary database file, only existing when database is open
• LIRS – Layered Intager Storage. Stores intageres with characters such as semicolons to create lists of data.
• MDA – Add-in file for Microsoft Access
• MDB – Microsoft Access database
• ADP – Microsoft Access project (used for accessing databases on a server)
• MDE – Compiled Microsoft Database (Access)
• MDF – Microsoft SQL Server Database
• MYD – MySQL MyISAM table data
• MYI – MySQL MyISAM table index
• NCF – Lotus Notes configuration file
• NSF – Lotus Notes database
• NTF – Lotus Notes database design template
• NV2 – QW Page NewViews object oriented accounting database
• ODB – LibreOffice Base or OpenOffice Base database
• ORA – Oracle tablespace files sometimes get this extension (also used for configuration files)
• PCONTACT – WinIM Contact file
• PDB – Palm OS Database
• PDI – Portable Database Image
• PDX – Corel Paradox database management
• PRC – Palm OS resource database
• SQL – bundled SQL queries
• REC – GNU recutils database
• REL – Sage Retrieve 4GL data file
• RIN – Sage Retrieve 4GL index file
• SDB – StarOffice’s StarBase
• SDF – SQL Compact Database file
• sqlite – SQLite
• UDL – Universal Data Link
• waData – Wakanda (software) database Data file
• waIndx – Wakanda (software) database Index file
• waModel – Wakanda (software) database Model file
• waJournal – Wakanda (software) database Journal file
• WDB – Microsoft Works Database
• WMDB – Windows Media Database file – The CurrentDatabase_360.wmdb file can contain file name, file properties, music, video, photo and playlist information.

Big Data (Distributed)[edit]

• Avro – Data format appropriate for ingestion of record based attributes. Distinguishing characteristic is schema is stored on each row enabling schema evolution.
• Parquet – Columnar data storage. It is typically used within the Hadoop ecosystem.
• ORC – Similar to Parquet, but has better data compression and schema evolution handling.

Desktop publishing[edit]

• AI – Adobe Illustrator
• AVE, ZAVE – Aquafadas
• CDR – CorelDRAW
• CHP, pub, STY, CAP, CIF, VGR, FRM – Ventura Publisher – Xerox (DOS / GEM)
• CPT – Corel Photo-Paint
• DTP – Greenstreet Publisher, GST PressWorks
• FM – Adobe FrameMaker
• GDRAW – Google Drive Drawing
• ILDOC – Broadvision Quicksilver document
• INDD – Adobe InDesign
• MCF – FotoInsight Designer
• PDF – Adobe Acrobat or Adobe Reader
• PMD – Adobe PageMaker
• PPP – Serif PagePlus
• PSD – Adobe Photoshop
• PUB – Microsoft Publisher
• QXD – QuarkXPress
• SLA, SCD – Scribus
• XCF – XCF: File format used by the GIMP, as well as other programs

Document[edit]

These files store formatted text and plain text.

• 0 – Plain Text Document, normally used for licensing
• 1ST – Plain Text Document, normally preceded by the words «README» (README.1ST)
• 600 – Plain Text Document, used in UNZIP history log
• 602 – Text602 (T602) document
• ABW – AbiWord document
• ACL – MS Word AutoCorrect List
• AFP – Advanced Function Presentation
• AMI – Lotus Ami Pro Amigaguide
• ANS – American National Standards Institute (ANSI) text
• ASC – ASCII text
• AWW – Ability Write
• CCF – Color Chat 1.0
• CSV – ASCII text as comma-separated values, used in spreadsheets and database management systems
• CWK – ClarisWorks-AppleWorks document
• DBK – DocBook XML sub-format
• DITA – Darwin Information Typing Architecture document
• DOC – Microsoft Word document
• DOCM – Microsoft Word macro-enabled document
• DOCX – Office Open XML document
• DOT – Microsoft Word document template
• DOTX – Office Open XML text document template
• DWD – DavkaWriter Heb/Eng word processor file
• EGT – EGT Universal Document
• EPUB – EPUB open standard for e-books
• EZW – Reagency Systems easyOFFER document^[6]
• FDX – Final Draft
• FTM – Fielded Text Meta
• FTX – Fielded Text (Declared)
• GDOC – Google Drive Document
• HTML – HyperText Markup Language (.html, .htm)
• HWP – Haansoft (Hancom) Hangul Word Processor document
• HWPML – Haansoft (Hancom) Hangul Word Processor Markup Language document
• LOG – Text log file
• LWP – Lotus Word Pro
• MBP – metadata for Mobipocket documents
• MD – Markdown text document
• ME – Plain text document normally preceded by the word «READ» (READ.ME)
• MCW – Microsoft Word for Macintosh (versions 4.0–5.1)
• Mobi – Mobipocket documents
• NB – Mathematica Notebook
• nb – Nota Bene Document (Academic Writing Software)
• NBP – Mathematica Player Notebook
• NEIS – 학교생활기록부 작성 프로그램 (Student Record Writing Program) Document
• NT – N-Triples RDF container (.nt)
• NQ – N-Quads RDF container (.nq)
• ODM – OpenDocument master document
• ODOC – Synology Drive Office Document
• ODT – OpenDocument text document
• OSHEET – Synology Drive Office Spreadsheet
• OTT – OpenDocument text document template
• OMM – OmmWriter text document
• PAGES – Apple Pages document
• PAP – Papyrus word processor document
• PER — Canadian Forces Personnel Appraisal System (CFPAS) Personnel Evaluation Report (PER)
• PDR — Canadian Forces Personnel Appraisal System (CFPAS) Personnel Development Report (PDR)
• PDAX – Portable Document Archive (PDA) document index file
• PDF – Portable Document Format
• QUOX – Question Object File Format for Quobject Designer or Quobject Explorer
• Radix-64 – Need helps!!!
• RTF – Rich Text document
• RPT – Crystal Reports
• SDW – StarWriter text document, used in earlier versions of StarOffice
• SE – Shuttle Document
• STW – OpenOffice.org XML (obsolete) text document template
• Sxw – OpenOffice.org XML (obsolete) text document
• TeX – TeX
• INFO – Texinfo
• Troff – Unix OS document processing system
• TXT – ASCII or Unicode plain text file
• UOF – Uniform Office Format
• UOML – Unique Object Markup Language
• VIA – Revoware VIA Document Project File
• WPD – WordPerfect document
• WPS – Microsoft Works document
• WPT – Microsoft Works document template
• WRD – WordIt! document
• WRF – ThinkFree Write
• WRI – Microsoft Write document
• xhtml, xht – XHTML eXtensible HyperText Markup Language
• XML – eXtensible Markup Language
• XPS – XPS: Open XML Paper Specification

Financial records[edit]

• MYO – MYOB Limited (Windows) File
• MYOB – MYOB Limited (Mac) File
• TAX – TurboTax File
• YNAB – You Need a Budget (YNAB) File

Financial data transfer formats[edit]

• IFX – Interactive Financial Exchange XML-based specification for various forms of financial transactions
• .ofx – Open Financial Exchange， open standard supported by CheckFree and Microsoft and partly by Intuit; SGML and later XML based
• QFX – proprietary pay-only format used only by Intuit
• .qif – Quicken Interchange Format open standard formerly supported by Intuit

Font file[edit]

• ABF – Adobe Binary Screen Font
• AFM – Adobe Font Metrics
• BDF – Bitmap Distribution Format
• BMF – ByteMap Font Format
• BRFNT – Binary Revolution Font Format
• FNT – Bitmapped Font – Graphics Environment Manager (GEM)
• FON – Bitmapped Font – Microsoft Windows
• MGF – MicroGrafx Font
• OTF – OpenType Font
• PCF – Portable Compiled Format
• PFA – Printer Font ASCII
• PFB – Printer Font Binary – Adobe
• PFM – Printer Font Metrics – Adobe
• AFM – Adobe Font Metrics
• FOND – Font Description resource – Mac OS
• SFD – FontForge spline font database Font
• SNF – Server Normal Format
• TDF – TheDraw Font
• TFM – TeX font metric
• .ttf, .ttc – TrueType Font
• UFO – Unified Font Object is a cross-platform, cross-application, human readable, future proof format for storing font data.
• WOFF – Web Open Font Format

General purpose[edit]

These file formats allow for the rapid creation of new binary file formats.

• IFDS — Incredibly Flexible Data Storage file format. File extension and the magic number does not have to be IFDS.^[7]

Geographic information system[edit]

• ASC – ASCII point of interest (POI) text file
• APR – ESRI ArcView 3.3 and earlier project file
• DEM – USGS DEM file format
• E00 – ARC/INFO interchange file format
• GeoJSON –Geographically located data in object notation
• GeoTIFF – Geographically located raster data
• GML – Geography Markup Language file^[8]
• GPX – XML-based interchange format
• ITN – TomTom Itinerary format
• MXD – ESRI ArcGIS project file, 8.0 and higher
• NTF – National Transfer Format file
• OV2 – TomTom POI overlay file
• SHP – ESRI shapefile
• TAB – MapInfo Table file format
• GeoTIFF – Geographically located raster data: text file giving corner coordinate, raster cells per unit, and rotation
• DTED – Digital Terrain Elevation Data
• KML – Keyhole Markup Language, XML-based

Graphical information organizers[edit]

• 3DT – 3D Topicscape, the database in which the meta-data of a 3D Topicscape is held, it is a form of 3D concept map (like a 3D mind-map) used to organize ideas, information, and computer files
• ATY – 3D Topicscape file, produced when an association type is exported; used to permit round-trip (export Topicscape, change files and folders as desired, re-import to 3D Topicscape)
• CAG – Linear Reference System
• FES – 3D Topicscape file, produced when a fileless occurrence in 3D Topicscape is exported to Windows. Used to permit round-trip (export Topicscape, change files and folders as desired, re-import them to 3D Topicscape)
• MGMF – MindGenius Mind Mapping Software file format
• MM – FreeMind mind map file (XML)
• MMP – Mind Manager mind map file
• TPC – 3D Topicscape file, produced when an inter-Topicscape topic link file is exported to Windows; used to permit round-trip (export Topicscape, change files and folders as desired, re-import to 3D Topicscape)

Graphics[edit]

Color palettes[edit]

• ACT – Adobe Color Table. Contains a raw color palette and consists of 256 24-bit RGB colour values.
• ASE – Adobe Swatch Exchange. Used by Adobe Photoshop, Illustrator, and InDesign.^[9]
• GPL – GIMP palette file. Uses a text representation of color names and RGB values. Various open source graphical editors can read this format,^[10] including GIMP, Inkscape, Krita,^[11] KolourPaint, Scribus, CinePaint, and MyPaint.^[12]
• PAL – Microsoft RIFF palette file

Color management[edit]

• ICC, ICM – Color profile conforming the specification of the ICC.

Raster graphics[edit]

Raster or bitmap files store images as a group of pixels.

Vector graphics[edit]

Vector graphics use geometric primitives such as points, lines, curves, and polygons to represent images.

• 3DS — 3D vector graphic file read by the Nintendo 3DS
• 3DV – 3-D wireframe graphics by Oscar Garcia
• AMF – Additive Manufacturing File Format
• AWG – Ability Draw
• AI – Adobe Illustrator Document
• CGM – Computer Graphics Metafile, an ISO Standard
• CDR – CorelDRAW Document
• CMX – CorelDRAW vector image
• DP – Drawing Program file for PERQ^[13]
• DRAWIO – Diagrams.net offline diagram
• DXF – ASCII Drawing Interchange file Format, used in AutoCAD and other CAD-programs
• E2D – 2-dimensional vector graphics used by the editor which is included in JFire
• EGT – EGT Universal Document, EGT Vector Draw images are used to draw vector to a website
• EPS – Encapsulated Postscript
• FS – FlexiPro file
• GBR – Gerber file
• ODG – OpenDocument Drawing
• MOVIE.BYU – 3D Vector file for polygons, coordinates and more complex shapes
• RenderMan – Displays Shading in both 2D and 3D scapes
• SVG – Scalable Vector Graphics, employs XML
• 3DMLW – Scene description languages (3D vector image formats)
• STL – STL: Stereo Lithographic data format (see STL (file format)) used by various CAD systems and stereo lithographic printing machines. See above.
• .wrl – Virtual Reality Modeling Language, VRML Uses this extension for the creation of 3D viewable web images.
• X3D – XML based file for communicating 3D graphics
• SXD – OpenOffice.org XML (obsolete) Drawing
• TGAX – Texture format used by Zwift
• V2D – voucher design used by the voucher management included in JFire
• VDOC – Vector format used in AnyCut, CutStorm, DrawCut, DragonCut, FutureDRAW, MasterCut, SignMaster, VinylMaster software by Future Corporation
• VSD – Vector format used by Microsoft Visio
• VSDX – Vector format used by MS Visio and opened by VSDX Annotator
• VND – Vision numeric Drawing file used in TypeEdit, Gravostyle.
• WMF – WMF: Windows Meta File
• EMF – EMF: Enhanced (Windows) MetaFile, an extension to WMF
• ART – Xara–Drawing (superseded by XAR)
• XAR – Xara–Drawing

3D graphics[edit]

3D graphics are 3D models that allow building models in real-time or non-real-time 3D rendering.

• 3DMF – QuickDraw 3D Metafile (.3dmf)
• 3DM – OpenNURBS Initiative 3D Model (used by Rhinoceros 3D) (.3dm)
• 3MF – Microsoft 3D Manufacturing Format (.3mf)^[3]
• 3DS – legacy 3D Studio Model (.3ds)
• ABC – Alembic (computer graphics)
• AC – AC3D Model (.ac)
• AMF – Additive Manufacturing File Format
• AN8 – Anim8or Model (.an8)
• AOI – Art of Illusion Model (.aoi)
• ASM – PTC Creo assembly (.asm)
• B3D – Blitz3D Model (.b3d)
• BLEND – Blender (.blend)
• BLOCK – Blender encrypted blend files (.block)
• BMD3 – Nintendo GameCube first-party J3D proprietary model format (.bmd)
• BDL4 – Nintendo GameCube and Wii first-party J3D proprietary model format (2002, 2006–2010) (.bdl)
• BRRES – Nintendo Wii first-party proprietary model format 2010+ (.brres)
• BFRES – Nintendo Wii U and later Switch first-party proprietary model format
• C4D – Cinema 4D (.c4d)
• Cal3D – Cal3D (.cal3d)
• CCP4 – X-ray crystallography voxels (electron density)
• CFL – Compressed File Library (.cfl)
• COB – Caligari Object (.cob)
• CORE3D – Coreona 3D Coreona 3D Virtual File(.core3d)
• CTM – OpenCTM (.ctm)
• DAE – COLLADA (.dae)
• DFF – RenderWare binary stream, commonly used by Grand Theft Auto III-era games as well as other RenderWare titles
• DPM – deepMesh (.dpm)
• DTS – Torque Game Engine (.dts)
• EGG – Panda3D Engine
• FACT – Electric Image (.fac)
• FBX – Autodesk FBX (.fbx)
• G – BRL-CAD geometry (.g)
• GLB – a binary form of glTF required to be loaded in Facebook 3D Posts. (.glb)
• GLM – Ghoul Mesh (.glm)
• glTF – the JSON-based standard developed by Khronos Group (.gltf)
• .hec – Hector Game Engine – Flatspace model format
• IO – Bricklink Stud.io 2.0 Model File (.io)
• IOB – Imagine (3D modeling software) (.iob)
• JAS – Cheetah 3D file (.jas)
• JMESH – Universal mesh data exchange file based on JMesh specification (.jmsh for text/JSON based, .bmsh for binary/UBJSON based)
• LDR – LDraw Model File (.ldr)
• LWO – Lightwave Object (.lwo)
• LWS – Lightwave Scene (.lws)
• LXF – LEGO Digital Designer Model file (.lxf)
• LXO – Luxology Modo (software) file (.lxo)
• M3D – Model3D, universal, engine-neutral format (.m3d)
• MA – Autodesk Maya ASCII File (.ma)
• MAX – Autodesk 3D Studio Max file (.max)
• MB – Autodesk Maya Binary File (.mb)
• MPD – LDraw Multi-Part Document Model File (.mpd)
• MD2 – MD2: Quake 2 model format (.md2)
• MD3 – MD3: Quake 3 model format (.md3)
• MD5 – MD5: Doom 3 model format (.md5)
• MDX – Blizzard Entertainment’s own model format (.mdx)
• MESH – New York University(.m)
• MESH – Meshwork Model (.mesh)
• MIOBJECT – Mine-Imator object file (.miobject)
• MIPARTICLE – Mine-Imator particle file (.miparticle)
• MIMODEL – Mine-Imator model file (.mimodel)
• MM3D – Misfit Model 3d (.mm3d)
• MPO – Multi-Picture Object – This JPEG standard is used for 3d images, as with the Nintendo 3DS
• MRC – MRC: voxels in cryo-electron microscopy
• NIF – Gamebryo NetImmerse File (.nif)
• OBJ – Wavefront .obj file (.obj)
• OFF – OFF Object file format (.off)
• OGEX – Open Game Engine Exchange (OpenGEX) format (.ogex)
• PLY – PLY: Polygon File Format / Stanford Triangle Format (.ply)
• PRC – Adobe PRC (embedded in PDF files)
• PRT – PTC Creo part (.prt)
• POV – POV-Ray document (.pov)
• R3D – Realsoft 3D (Real-3D) (.r3d)
• RWX – RenderWare Object (.rwx)
• SIA – Nevercenter Silo Object (.sia)
• SIB – Nevercenter Silo Object (.sib)
• SKP – Google Sketchup file (.skp)
• SLDASM – SolidWorks Assembly Document (.sldasm)
• SLDPRT – SolidWorks Part Document (.sldprt)
• SMD – Valve Studiomdl Data format (.smd)
• U3D – Universal 3D format (.u3d)
• USD – Universal Scene Description (.usd)
• USDA – Universal Scene Description , Human-readable text format (.usda)
• USDC – Universal Scene Description , Binary format (.usdc)
• USDZ – Universal Scene Description Zip (.usdz)
• VIM – Revizto visual information model format (.vimproj)
• VRML97 – VRML Virtual reality modeling language (.wrl)
• VUE – Vue scene file (.vue)
• VWX – Vectorworks (.vwx)
• WINGS – Wings3D (.wings)
• W3D – Westwood 3D Model (.w3d)
• X – DirectX 3D Model (.x)
• X3D – Extensible 3D (.x3d)
• Z3D – Zmodeler (.z3d)
• ZBMX – Mecabricks Blender Add-On (.zbmx)

Links and shortcuts[edit]

• Alias – Alias (Mac OS)
• JNLP – Java Network Launching Protocol, an XML file used by Java Web Start for starting Java applets over the Internet
• LNK – binary-format file shortcut in Microsoft Windows 95 and later
• APPREF-MS – File shortcut format used by ClickOnce
• NAL – ZENworks Instant shortcut (opens a .EXE not on the C:/ )
• URL – INI file pointing to a URL bookmarks/Internet shortcut in Microsoft Windows
• WEBLOC – Property list file pointing to a URL bookmarks/Internet shortcut in macOS
• SYM – Symbolic link
• .desktop – Desktop entry on Linux Desktop environments

Mathematical[edit]

• Harwell-Boeing – a file format designed to store sparse matrices
• MML – MathML – Mathematical Markup Language
• ODF – OpenDocument Math Formula
• SXM – OpenOffice.org XML (obsolete) Math Formula

Object code, executable files, shared and dynamically linked libraries[edit]

• 8BF – files plugins for some photo editing programs including Adobe Photoshop, Paint Shop Pro, GIMP and Helicon Filter.
• .a — a static library on on Unix-like systems
• .a – Objective C native static library
• a.out – (no suffix for executable image, .o for object files, .so for shared object files) classic UNIX object format, now often superseded by ELF
• APK – Android Application Package
• APP – A folder found on macOS systems containing program code and resources, appearing as one file.
• BAC – an executable image for the RSTS/E system, created using the BASIC-PLUS COMPILE command^[14]
• BPL – a Win32 PE file created with Borland Delphi or C++Builder containing a package.
• Bundle – a Macintosh plugin created with Xcode or make which holds executable code, data files, and folders for that code.
• .class – Compiled Java bytecode
• COFF – (no suffix for executable image, .o for object files) UNIX Common Object File Format, now often superseded by ELF
• COM – Simple executable format used by CP/M and DOS.
• DCU – Delphi compiled unit
• DLL – Dynamic library used in Windows and OS/2 to store data, resources and code.
• DOL – the format used by the GameCube and Wii, short for Dolphin, which was the codename of the GameCube.
• .EAR – archives of Java enterprise applications
• ELF – (no suffix for executable image, .o for object files, .so for shared object files) used in many modern Unix and Unix-like systems, including Solaris, other System V Release 4 derivatives, Linux, and BSD)
• .exe – DOS executable (.exe: used in DOS)
• .EXE – New Executable (used in multitasking («European») MS-DOS 4.0, 16-bit Microsoft Windows, and OS/2)
• .EXE – Portable Executable used in Microsoft Windows and some other systems
• .ipa, .IPA – file extension for apple IOS application executable file. Another form of zip file.
• .JAR – archives of Java class files
• JEFF – a file format allowing execution directly from static memory^[15]
• .ko — Loadable kernel module
• LIB — a static library on Microsoft platforms
• LIST – variable list
• Mach-O – (no suffix for executable image, .o for object files, .dylib and .bundle for shared object files) Mach-based systems, notably native format of macOS, iOS, watchOS, and tvOS
• .NLM – NetWare Loadable Module the native 32-bit binaries compiled for Novell’s NetWare Operating System (versions 3 and newer)
• .o – un-linked object files directly from the compiler
• OBJ — object file on Windows
• RLL – used in Microsoft operating systems together with a DLL file to store program resources
• .s1es – Executable used for S1ES learning system.
• .so – shared library, typically ELF
• .VAP – Value Added Process the native 16-bit binaries compiled for Novell’s NetWare Operating System (version 2, NetWare 286, Advanced NetWare, etc.)
• WAR, .WAR – .WAR are archives of Java Web applications
• .XAP – Windows Phone package
• XBE – XBE is Xbox executable
• XCOFF – (no suffix for executable image, .o for object files, .a for shared object files) extended COFF, used in AIX
• XEX – XEX is Xbox 360 executable
• .XPI – PKZIP archive that can be run by Mozilla web browsers to install software.

Object extensions:

• .OCX – .OCX are Object Control extensions
• .TLB – .TLB are Windows Type Library
• .VBX – .VBX are Visual Basic extensions

Page description language[edit]

• DVI – DVI are Device independent format
• .egt – Universal Document can be used to store CSS type styles
• PLD – PLD (Need to be added!!!)
• PCL – PCL (Need to be added!!!)
• PDF – PDF are Portable Document Format
• .ps, .ps, .gz – PostScript (Need to be added!!!)
• SNP – SNP are Microsoft Access Report Snapshot
• XPS – XPS
• XSL-FO – XSL-FO (Formatting Objects)
• Configurations, Metadata
  • CSS – CSS are Cascading Style Sheets
  • .xslt, .xsl – XML Style Sheet
  • .tpl – Web template

Personal information manager[edit]

• MNB — MyInfo notebook
• MSG – Microsoft Outlook task manager
• ORG – Lotus Organizer PIM package
• ORG – Emacs Org-Mode Mindmanager, contacts, calendar, email-integration
• PST, OST – Microsoft Outlook email communication
• SC2 – Microsoft Schedule+ calendar

Presentation[edit]

• GSLIDES – Google Drive Presentation
• KEY, KEYNOTE – Apple Keynote Presentation
• NB – Mathematica Slideshow
• NBP – Mathematica Player slideshow
• ODP – OpenDocument Presentation
• OTP – OpenDocument Presentation template
• PEZ – Prezi Desktop Presentation
• POT – Microsoft PowerPoint template
• PPS – Microsoft PowerPoint Show
• PPT – Microsoft PowerPoint Presentation
• PPTX – Office Open XML Presentation
• PRZ – Lotus Freelance Graphics
• SDD – StarOffice’s StarImpress
• SHF – ThinkFree Show
• SHOW – Haansoft(Hancom) Presentation software document
• SHW – Corel Presentations slide show creation
• SLP – Logix-4D Manager Show Control Project
• SSPSS – SongShow Plus Slide Show
• STI – OpenOffice.org XML (obsolete) Presentation template
• SXI – OpenOffice.org XML (obsolete) Presentation
• THMX – Microsoft PowerPoint theme template
• WATCH – Dataton Watchout Presentation

Project management software[edit]

• MPP – Microsoft Project

Reference management software[edit]

Formats of files used for bibliographic information (citation) management.

• bib – BibTeX
• enl – EndNote
• ris – Research Information Systems RIS (file format)

Scientific data (data exchange)[edit]

• .fits – FITS (Flexible Image Transport System) standard data format for astronomy
• Silo – Silo, a storage format for visualization developed at Lawrence Livermore National Laboratory
• SPC – SPC, spectroscopic data
• EAS3 – binary format for structured data
• EOSSA – Electro-Optic Space Situational Awareness format
• OST – (Open Spatio-Temporal) extensible, mainly images with related data, or just pure data; meant as an open alternative for microscope images
• CCP4 – CCP4, X-ray crystallography voxels (electron density)
• MRC – MRC, voxels in cryo-electron microscopy
• HITRAN – spectroscopic data with one optical/infrared transition per line in the ASCII file (.hit)
• .root – hierarchical platform-independent compressed binary format used by ROOT
• SDF – Simple Data Format (SDF), a platform-independent, precision-preserving binary data I/O format capable of handling large, multi-dimensional arrays.
• MYD – Everfine LEDSpec software file for LED measurements
• CSDM – (Core Scientific Dataset Model) model for multi-dimensional and correlated datasets from various spectroscopies, diffraction, microscopy, and imaging techniques (.csdf, .csdfe).^[16]

Multi-domain[edit]

• NetCDF – Network common data format
• HDR, HDF, h4, h5 – Hierarchical Data Format
• SDXF – SDXF, (Structured Data Exchange Format)
• CDF – Common Data Format
• CGNS – CGNS, CFD General Notation System
• FMF – Full-Metadata Format

Meteorology[edit]

• GRIB – Grid in Binary, WMO format for weather model data
• BUFR – WMO format for weather observation data
• PP – UK Met Office format for weather model data
• NASA-Ames – Simple text format for observation data. First used in aircraft studies of the atmosphere.

Chemistry[edit]

• CML – Chemical Markup Language (CML) (.cml)
• .mol, .sd, .sdf – Chemical table file (CTab)
• .dx, .jdx – Joint Committee on Atomic and Molecular Physical Data (JCAMP)
• .smi – Simplified molecular input line entry specification (SMILES)

Mathematics[edit]

• .g6, .s6 – graph6, sparse6, ASCII encoding of Adjacency matrices

Biology[edit]

Molecular biology and bioinformatics:

• AB1 – In DNA sequencing, chromatogram files used by instruments from Applied Biosystems
• ACE – A sequence assembly format
• ASN.1 – Abstract Syntax Notation One, is an International Standards Organization (ISO) data representation format used to achieve interoperability between platforms. NCBI uses ASN.1 for the storage and retrieval of data such as nucleotide and protein sequences, structures, genomes, and PubMed records.
• BAM – Binary Alignment/Map format (compressed SAM format)
• BCF – Binary compressed VCF format
• BED – The browser extensible display format is used for describing genes and other features of DNA sequences
• CAF – Common Assembly Format for sequence assembly
• CRAM – compressed file format for storing biological sequences aligned to a reference sequence
• DDBJ – The flatfile format used by the DDBJ to represent database records for nucleotide and peptide sequences from DDBJ databases.
• EMBL – The flatfile format used by the EMBL to represent database records for nucleotide and peptide sequences from EMBL databases.
• FASTA – The FASTA format, for sequence data. Sometimes also given as FNA or FAA (Fasta Nucleic Acid or Fasta Amino Acid).
• FASTQ – The FASTQ format, for sequence data with quality. Sometimes also given as QUAL.
• GCPROJ – The Genome Compiler project. Advanced format for genetic data to be designed, shared and visualized.
• GenBank – The flatfile format used by the NCBI to represent database records for nucleotide and peptide sequences from the GenBank and RefSeq databases
• GFF – The General feature format is used to describe genes and other features of DNA, RNA, and protein sequences
• GTF – The Gene transfer format is used to hold information about gene structure
• MAF – The Multiple Alignment Format stores multiple alignments for whole-genome to whole-genome comparisons [1]
• NCBI – Structured ASN.1 format used at National Center for Biotechnology Information for DNA and protein data
• NEXUS – The Nexus file encodes mixed information about genetic sequence data in a block structured format
• NeXML – XML format for phylogenetic trees
• NWK – The Newick tree format is a way of representing graph-theoretical trees with edge lengths using parentheses and commas and useful to hold phylogenetic trees.
• PDB – structures of biomolecules deposited in Protein Data Bank, also used to exchange protein and nucleic acid structures
• PHD – Phred output, from the base-calling software Phred
• PLN – Protein Line Notation used in proteax software specification
• SAM – SAM, Sequence Alignment Map format, in which the results of the 1000 Genomes Project will be released
• SBML – The Systems Biology Markup Language is used to store biochemical network computational models
• SCF – Staden chromatogram files used to store data from DNA sequencing
• SFF – Standard Flowgram Format
• SRA – format used by the National Center for Biotechnology Information Short Read Archive to store high-throughput DNA sequence data
• Stockholm – The Stockholm format for representing multiple sequence alignments
• Swiss-Prot – The flatfile format used to represent database records for protein sequences from the Swiss-Prot database
• VCF – Variant Call Format, a standard created by the 1000 Genomes Project that lists and annotates the entire collection of human variants (with the exception of approximately 1.6 million variants).

Biomedical imaging[edit]

• .dcm – Digital Imaging and Communications in Medicine (DICOM)
• NIfTI – Neuroimaging Informatics Technology Initiative
• .nii – single-file (combined data and meta-data) style
• .nii.gz – gzip-compressed, used transparently by some software, notably the FMRIB Software Library (FSL)
• .gii – single-file (combined data and meta-data) style; NIfTI offspring for brain surface data
• .img, .hdr – dual-file (separate data and meta-data, respectively) style
• .BRIK, .HEAD – AFNI data, meta-data
• .MGH – uncompressed, Massachusetts General Hospital imaging format, used by the FreeSurfer brain analysis package
• .MGZ – zip-compressed, Massachusetts General Hospital imaging format, used by the FreeSurfer brain analysis package
• .img, .hdr – Analyze data, meta-data
• MINC – Medical Imaging NetCDF format
• .mnc – previously based on NetCDF; since version 2.0, based on HDF5

Biomedical signals (time series)[edit]

• ACQ – AcqKnowledge format for Windows/PC from Biopac Systems Inc., Goleta, CA, USA
• ADICHT – LabChart format from ADInstruments Pty Ltd, Bella Vista NSW, Australia
• BCI2000 – The BCI2000 project, Albany, NY, USA
• BDF – BioSemi data format from BioSemi B.V. Amsterdam, Netherlands
• BKR – The EEG data format developed at the University of Technology Graz, Austria
• CFWB – Chart Data Format from ADInstruments Pty Ltd, Bella Vista NSW, Australia
• DICOM – Waveform An extension of Dicom for storing waveform data
• ecgML – A markup language for electrocardiogram data acquisition and analysis
• EDF, EDF+ – European Data Format
• FEF – File Exchange Format for Vital signs, CEN TS 14271
• GDF – The General Data Format for biomedical signals
• HL7aECG – Health Level 7 v3 annotated ECG
• MFER – Medical waveform Format Encoding Rules
• OpenXDF – Open Exchange Data Format from Neurotronics, Inc., Gainesville, FL, USA
• SCP-ECG – Standard Communication Protocol for Computer assisted electrocardiography EN1064:2007
• SIGIF – A digital SIGnal Interchange Format with application in neurophysiology
• WFDB – Format of Physiobank
• XDF – eXtensible Data Format

Other biomedical formats[edit]

• HL7 – Health Level 7, a framework for exchange, integration, sharing, and retrieval of health information electronically
• xDT – a family of data exchange formats for medical records

Biometric formats[edit]

• CBF – Common Biometric Format, based on CBEFF 2.0 (Common Biometric ExFramework).
• EBF – Extended Biometric Format, based on CBF but with S/MIME encryption support and semantic extensions
• CBFX – XML Common Biometric Format, based upon XCBF 1.1 (OASIS XML Common Biometric Format)
• EBFX – XML Extended Biometric Format, based on CBFX but with W3C XML Encryption support and semantic extensions

Programming languages and scripts[edit]

• ADB – Ada body
• ADS – Ada specification
• AHK – AutoHotkey script file
• APPLESCRIPT – applescript: see SCPT
• AS – Adobe Flash ActionScript File
• AU3 – AutoIt version 3
• AWK — AWK
• BAT – Batch file
• BAS – QBasic & QuickBASIC
• BTM — Batch file
• CLASS — Compiled Java binary
• CLJS – ClojureScript
• CMD – Batch file
• Coffee – CoffeeScript
• C – C
• CIA — Nintendo 3DS Software Installation File
• CPP – C++
• CS – C#
• INO – Arduino sketch (program)
• EGG – Chicken
• EGT – EGT Asterisk Application Source File, EGT Universal Document
• ERB – Embedded Ruby, Ruby on Rails Script File
• GO – Go
• HTA – HTML Application
• IBI – Icarus script
• ICI – ICI
• IJS – J script
• .ipynb – IPython Notebook
• ITCL – Itcl
• JS – JavaScript and JScript
• JSFL – Adobe JavaScript language
• .kt – Kotlin
• LUA – Lua
• M – Mathematica package file
• MRC – mIRC Script
• NCF – NetWare Command File^[17][18] (scripting for Novell’s NetWare OS)
• NUC – compiled script
• NUD – C++ External module written in C++
• NUT – Squirrel
• nqp – Raku language Not Quite Perl, or Raku bootstrapping language^[19]
• O — Compiled and optimized C/C++ binary
• pde – Processing (programming language), Processing script
• PHP – PHP
• PHP? – PHP (? = version number)
• PL – Perl
• PM – Perl module
• PS1 – Windows PowerShell shell script
• PS1XML – Windows PowerShell format and type definitions
• PSC1 – Windows PowerShell console file
• PSD1 – Windows PowerShell data file
• PSM1 – Windows PowerShell module file
• PY – Python
• PYC – Python byte code files
• PYO – Python
• R – R scripts
• r – REBOL scripts
• raku – Raku language Raku script (compiled into memory)^[20]
• rakumod – Raku language Raku module (precompiled)
• rakudoc – Raku language Raku documentation file (a slang or sublanguage of Raku)
• rakutest – Raku language Unit test files in Raku
• RB – Ruby
• RDP – RDP connection
• red – Red scripts
• RS – Rust (programming language)
• SB2, SB3 – Scratch
• SCPT – Applescript
• SCPTD – See SCPT.
• SDL – State Description Language
• SH – Shell script
• SYJS – SyMAT JavaScript
• SYPY – SyMAT Python
• TCL – Tcl
• TNS – Ti-Nspire Code/File
• TS – TypeScript
• VBS – Visual Basic Script
• XPL – XProc script/pipeline
• ebuild – Gentoo Linux’s portage package.

Security[edit]

Authentication and general encryption formats are listed here.

• OMF – OpenPGP Message Format used by Pretty Good Privacy, GNU Privacy Guard, and other OpenPGP software; can contain keys, signed data, or encrypted data; can be binary or text («ASCII armored»)

Certificates and keys[edit]

• GXK – Galaxkey, an encryption platform for authorized, private and confidential email communication^{[citation needed]}
• .ssh – OpenSSH private key, Secure Shell private key; format generated by ssh-keygen or converted from PPK with PuTTYgen^[21][22][23]
• .pub – OpenSSH public key, Secure Shell public key; format generated by ssh-keygen or PuTTYgen^[21][22][23]
• .ppk – PuTTY private key, Secure Shell private key, in the format generated by PuTTYgen instead of the format used by OpenSSH^[21][22][23]
• .nSign – nSign public key nSign public key in a custom format^[24]

X.509[edit]

• .cer, .crt, .der – Distinguished Encoding Rules stores certificates
• .p7b, .p7c – PKCS#7 SignedData commonly appears without main data, just certificates or certificate revocation lists (CRLs)
• .p12, .pfx – PKCS#12 can store public certificates and private keys
• PEM – Privacy-enhanced Electronic Mail: full format not widely used, but often used to store Distinguished Encoding Rules in Base64 format
• PFX – Microsoft predecessor of PKCS#12

Encrypted files[edit]

This section shows file formats for encrypted general data, rather than a specific program’s data.

• AXX – Encrypted file, created with AxCrypt
• EEA – An encrypted CAB, ostensibly for protecting email attachments
• TC – Virtual encrypted disk container, created by TrueCrypt
• KODE – Encrypted file, created with KodeFile
• nSignE – An encrypted private key, created by nSign^[24]

Password files[edit]

Password files (sometimes called keychain files) contain lists of other passwords, usually encrypted.

• BPW – Encrypted password file created by Bitser password manager
• KDB – KeePass 1 database
• KDBX – KeePass 2 database

Signal data (non-audio)[edit]

• ACQ – AcqKnowledge format for Windows/PC from Biopac
• ADICHT – LabChart format from ADInstruments
• BKR – The EEG data format developed at the University of Technology Graz
• BDF, CFG – Configuration file for Comtrade data
• CFWB – Chart Data format from ADInstruments
• DAT – Raw data file for Comtrade data
• EDF – European data format
• FEF – File Exchange Format for Vital signs
• GDF – General data formats for biomedical signals
• GMS – Gesture And Motion Signal format
• IROCK – intelliRock Sensor Data File Format
• MFER – Medical waveform Format Encoding Rules
• SAC – Seismic Analysis Code, earthquake seismology data format^[25]
• SCP-ECG – Standard Communication Protocol for Computer assisted electrocardiography
• SEED, MSEED – Standard for the Exchange of Earthquake Data, seismological data and sensor metadata^[26]
• SEGY – Reflection seismology data format
• SIGIF – SIGnal Interchange Format
• WIN, WIN32 – NIED/ERI seismic data format (.cnt)^[27]

Sound and music[edit]

Lossless audio[edit]

Uncompressed[edit]

• 8SVX – Commodore-Amiga 8-bit sound (usually in an IFF container)
• 16SVX – Commodore-Amiga 16-bit sound (usually in an IFF container)
• AIFF, AIF, AIFC – Audio Interchange File Format
• AU – Simple audio file format introduced by Sun Microsystems
• AUP3 — Audacity’s file for when you save a song
• BWF – Broadcast Wave Format, an extension of WAVE
• CDDA – Compact Disc Digital Audio
• DSF, DFF – Direct Stream Digital audio file, also used in Super Audio CD
• RAW – Raw samples without any header or sync
• WAV – Microsoft Wave
• CWAV — file read by the Nintendo 3DS for Home-screen sound effects

Compressed[edit]

• RA, RM – RealAudio format
• FLAC – Free lossless codec of the Ogg project
• LA – Lossless audio
• PAC – LPAC
• APE – Monkey’s Audio
• OFR, OFS, OFF – OptimFROG
• RKA – RKAU
• SHN – Shorten
• TAK – Tom’s Lossless Audio Kompressor^[28]
• THD – Dolby TrueHD
• TTA – Free lossless audio codec (True Audio)
• WV – WavPack
• WMA – Windows Media Audio 9 Lossless
• BCWAV — Nintendo 3DS Home-screen BGM file
• BRSTM – Binary Revolution Stream^[29]
• DTS, DTSHD, DTSMA – DTS (sound system)
• AST – Nintendo Audio Stream
• AW – Nintendo Audio Sample used in first-party games
• PSF – Portable Sound Format, PlayStation variant (originally PlayStation Sound Format)

Lossy audio[edit]

• AC3 – Usually used for Dolby Digital tracks
• AMR – For GSM and UMTS based mobile phones
• MP1 – MPEG Layer 1
• MP2 – MPEG Layer 2
• MP3 – MPEG Layer 3
• SPX – Speex (Ogg project, specialized for voice, low bitrates)
• GSM – GSM Full Rate, originally developed for use in mobile phones
• WMA – Windows Media Audio
• AAC – Advanced Audio Coding (usually in an MPEG-4 container)
• MPC – Musepack
• VQF – Yamaha TwinVQ
• OTS – Audio File (similar to MP3, with more data stored in the file and slightly better compression; designed for use with OtsLabs’ OtsAV)
• SWA – Adobe Shockwave Audio (Same compression as MP3 with additional header information specific to Adobe Director)
• VOX – Dialogic ADPCM Low Sample Rate Digitized Voice
• VOC – Creative Labs Soundblaster Creative Voice 8-bit & 16-bit Also output format of RCA Audio Recorders
• DWD – DiamondWare Digitized
• SMP – Turtlebeach SampleVision
• OGG – Ogg Vorbis

Tracker modules and related[edit]

• MOD – Soundtracker and Protracker sample and melody modules
• MT2 – MadTracker 2 module
• S3M – Scream Tracker 3 module
• XM – Fast Tracker module
• IT – Impulse Tracker module
• NSF – NES Sound Format
• MID, MIDI – Standard MIDI file; most often just notes and controls but occasionally also sample dumps (.mid, .rmi)
• FTM – FamiTracker Project file
• BTM – BambooTracker Project file

Sheet music files[edit]

• ABC – ABC Notation sheet music file
• DARMS – DARMS File Format also known as the Ford-Columbia Format
• ETF – Enigma Transportation Format abandoned sheet music exchange format
• GP – Guitar Pro sheet music and tablature file
• KERN – Kern File Format sheet music file
• LY – LilyPond sheet music file
• MEI – Music Encoding Initiative file format that attempts to encode all musical notations
• MIDI — MIDI file format that is a music sheet for instruments
• MUS, MUSX – Finale sheet music file
• MXL, XML – MusicXML standard sheet music exchange format
• MSCX, MSCZ – MuseScore sheet music file
• SMDL – Standard Music Description Language sheet music file
• SIB – Sibelius sheet music file

Other file formats pertaining to audio[edit]

• NIFF – Notation Interchange File Format
• PTB – Power Tab Editor tab
• ASF – Advanced Systems Format
• CUST – DeliPlayer custom sound format
• GYM – Genesis YM2612 log
• JAM – Jam music format
• MNG – Background music for the Creatures game series, starting from Creatures 2
• RMJ – RealJukebox Media used for RealPlayer
• SID – Sound Interface Device – Commodore 64 instructions to play SID music and sound effects
• SPC – Super NES sound format
• TXM – Track ax media
• VGM – Stands for «Video Game Music», log for several different chips
• YM – Atari ST/Amstrad CPC YM2149 sound chip format
• PVD – Portable Voice Document used for Oaisys & Mitel call recordings

Playlist formats[edit]

• AIMPPL – AIMP Playlist format
• ASX – Advanced Stream Redirector
• RAM – Real Audio Metafile For RealAudio files only.
• XPL – HDi playlist
• XSPF – XML Shareable Playlist Format
• ZPL – Xbox Music (Formerly Zune) Playlist format from Microsoft
• M3U – Multimedia playlist file
• PLS – Multimedia playlist, originally developed for use with the museArc

Audio editing and music production[edit]

• ALS – Ableton Live set
• ALC – Ableton Live clip
• ALP – Ableton Live pack
• ATMOS, AUDIO, METADATA – Dolby Atmos Rendering and Mastering related file
• AUP – Audacity project file
• AUP3 – Audacity 3.0 project file
• BAND – GarageBand project file
• CEL – Adobe Audition loop file (Cool Edit Loop)
• CAU – Caustic project file
• CPR – Steinberg Cubase project file
• CWP – Cakewalk Sonar project file
• DRM – Steinberg Cubase drum file
• DMKIT – Image-Line’s Drumaxx drum kit file
• ENS – Native Instruments Reaktor Ensemble
• FLM – Image Line FL Studio Mobile project file
• FLP – Image Line FL Studio project file
• GRIR – Native Instruments Komplete Guitar Rig Impulse Response
• LOGIC – Logic Pro X project file
• MMP – LMMS project file (alternatively MMPZ for compressed formats)
• MMR – MAGIX Music Maker project file
• MX6HS – Mixcraft 6 Home Studio project file
• NPR – Steinberg Nuendo project file
• OMF, OMFI – Open Media Framework Interchange OMFI succeeds OMF (Open Media Framework)
• PTX – Pro Tools 10 or later project file
• PTF – Pro Tools 7 up to Pro Tools 9 project file
• PTS – Legacy Pro Tools project file
• RIN – Soundways RIN-M file containing sound recording participant credits and song information
• RPP, RPP-BAK – REAPER project file
• REAPEAKS – REAPER peak (waveform cache) file
• SES – Adobe Audition multitrack session file
• SFK – Sound Forge waveform cache file
• SFL – Sound Forge sound file
• SNG – MIDI sequence file (MidiSoft, Korg, etc.) or n-Track Studio project file
• STF – StudioFactory project file. It contains all necessary patches, samples, tracks and settings to play the file
• SND – Akai MPC sound file
• SYN – SynFactory project file. It contains all necessary patches, samples, tracks and settings to play the file
• UST – Utau Editor sequence excluding wave-file
• VCLS – VocaListener project file
• VPR – Vocaloid 5 Editor sequence excluding wave-file
• VSQ – Vocaloid 2 Editor sequence excluding wave-file
• VSQX – Vocaloid 3 & 4 Editor sequence excluding wave-file
• 🗿 – ThirtyDollar Project file

Recorded television formats[edit]

• DVR-MS – Windows XP Media Center Edition’s Windows Media Center recorded television format
• WTV – Windows Vista’s and up Windows Media Center recorded television format

Source code for computer programs[edit]

• ADA, ADB, 2.ADA – Ada (body) source
• ADS, 1.ADA – Ada (specification) source
• ASM, S – Assembly language source
• BAS – BASIC, FreeBASIC, Visual Basic, BASIC-PLUS source,^[14] PICAXE basic
• BB – Blitz Basic Blitz3D
• BMX – Blitz Basic BlitzMax
• C – C source
• CLJ – Clojure source code
• CLS – Visual Basic class
• COB, CBL – COBOL source
• CPP, CC, CXX, C, CBP – C++ source
• CS – C# source
• CSPROJ – C# project (Visual Studio .NET)
• D – D source
• DBA – DarkBASIC source
• DBPro123 – DarkBASIC Professional project
• E – Eiffel source
• EFS – EGT Forever Source File
• EGT – EGT Asterisk Source File, could be J, C#, VB.net, EF 2.0 (EGT Forever)
• EL – Emacs Lisp source
• FOR, FTN, F, F77, F90 – Fortran source
• FRM – Visual Basic form
• FRX – Visual Basic form stash file (binary form file)
• FTH – Forth source
• GED – Game Maker Extension Editable file as of version 7.0
• GM6 – Game Maker Editable file as of version 6.x
• GMD – Game Maker Editable file up to version 5.x
• GMK – Game Maker Editable file as of version 7.0
• GML – Game Maker Language script file
• GO – Go source
• H – C/C++ header file
• HPP, HXX – C++ header file
• HS – Haskell source
• I – SWIG interface file
• INC – Turbo Pascal included source
• JAVA – Java source
• L – lex source
• LGT – Logtalk source
• LISP – Common Lisp source
• M – Objective-C source
• M – MATLAB
• M – Mathematica
• M4 – m4 source
• ML – Standard ML and OCaml source
• MSQR – M² source file, created by Mattia Marziali
• N – Nemerle source
• NB – Nuclear Basic source
• P – Parser source
• PAS, PP, P – Pascal source (DPR for projects)
• PHP, PHP3, PHP4, PHP5, PHPS, Phtml – PHP source
• PIV – Pivot stickfigure animator
• PL, PM – Perl
• PLI, PL1 – PL/I
• PRG – Ashton-Tate; dbII, dbIII and dbIV, db, db7, clipper, Microsoft Fox and FoxPro, harbour, xharbour, and Xbase
• PRO – IDL
• POL – Apcera Policy Language doclet
• PY – Python source
• R – R source
• raku, rakumod, rakudoc, rakutest, nqp – Raku Language
• RED – Red source
• REDS – Red/System source
• RB – Ruby source
• RESX – Resource file for .NET applications
• RC, RC2 – Resource script files to generate resources for .NET applications
• RKT, RKTL – Racket source
• SCALA – Scala source
• SCI, SCE – Scilab
• SCM – Scheme source
• SD7 – Seed7 source
• SKB, SKC – Sage Retrieve 4GL Common Area (Main and Amended backup)
• SKD – Sage Retrieve 4GL Database
• SKF, SKG – Sage Retrieve 4GL File Layouts (Main and Amended backup)
• SKI – Sage Retrieve 4GL Instructions
• SKK – Sage Retrieve 4GL Report Generator
• SKM – Sage Retrieve 4GL Menu
• SKO – Sage Retrieve 4GL Program
• SKP, SKQ – Sage Retrieve 4GL Print Layouts (Main and Amended backup)
• SKS, SKT – Sage Retrieve 4GL Screen Layouts (Main and Amended backup)
• SKZ – Sage Retrieve 4GL Security File
• SLN – Visual Studio solution
• SPIN – Spin source (for Parallax Propeller microcontrollers)
• STK – Stickfigure file for Pivot stickfigure animator
• SWG – SWIG source code
• TCL – Tcl source code
• VAP – Visual Studio Analyzer project
• VB – Visual Basic.NET source
• VBG – Visual Studio compatible project group
• VBP, VIP – Visual Basic project
• VBPROJ – Visual Basic .NET project
• VCPROJ – Visual C++ project
• VDPROJ – Visual Studio deployment project
• XPL – XProc script/pipeline
• XQ – XQuery file
• XSL – XSLT stylesheet
• Y – yacc source

Spreadsheet[edit]

• 123 – Lotus 1-2-3
• AB2 – Abykus worksheet
• AB3 – Abykus workbook
• AWS – Ability Spreadsheet
• BCSV – Nintendo proprietary table format
• CLF – ThinkFree Calc
• CELL – Haansoft(Hancom) SpreadSheet software document
• CSV – Comma-Separated Values
• GSHEET – Google Drive Spreadsheet
• numbers – An Apple Numbers Spreadsheet file
• gnumeric – Gnumeric spreadsheet, a gziped XML file
• LCW – Lucid 3-D
• ODS – OpenDocument spreadsheet
• OTS – OpenDocument spreadsheet template
• QPW – Quattro Pro spreadsheet
• SDC – StarOffice StarCalc Spreadsheet
• SLK – SYLK (SYmbolic LinK)
• STC – OpenOffice.org XML (obsolete) Spreadsheet template
• SXC – OpenOffice.org XML (obsolete) Spreadsheet
• TAB – tab delimited columns; also TSV (Tab-Separated Values)
• TXT – text file
• VC – Visicalc
• WK1 – Lotus 1-2-3 up to version 2.01
• WK3 – Lotus 1-2-3 version 3.0
• WK4 – Lotus 1-2-3 version 4.0
• WKS – Lotus 1-2-3
• WKS – Microsoft Works
• WQ1 – Quattro Pro DOS version
• XLK – Microsoft Excel worksheet backup
• XLS – Microsoft Excel worksheet sheet (97–2003)
• XLSB – Microsoft Excel binary workbook
• XLSM – Microsoft Excel Macro-enabled workbook
• XLSX – Office Open XML worksheet sheet
• XLR – Microsoft Works version 6.0
• XLT – Microsoft Excel worksheet template
• XLTM – Microsoft Excel Macro-enabled worksheet template
• XLW – Microsoft Excel worksheet workspace (version 4.0)

Tabulated data[edit]

• TSV – Tab-separated values
• CSV – Comma-separated values
• db – databank format; accessible by many econometric applications
• dif – accessible by many spreadsheet applications

Video[edit]

• AAF – mostly intended to hold edit decisions and rendering information, but can also contain compressed media essence
• 3GP – the most common video format for cell phones
• GIF – Animated GIF (simple animation; until recently often avoided because of patent problems)
• ASF – container (enables any form of compression to be used; MPEG-4 is common; video in ASF-containers is also called Windows Media Video (WMV))
• AVCHD – Advanced Video Codec High Definition
• AVI – container (a shell, which enables any form of compression to be used)
• .bik – BIK Bink Video file. A video compression system developed by RAD Game Tools
• BRAW – a video format used by Blackmagic’s Ursa Mini Pro 12K cameras.
• CAM – aMSN webcam log file
• COLLAB – Blackboard Collaborate session recording
• DAT – video standard data file (automatically created when we attempted to burn as video file on the CD)
• DVR-MS – Windows XP Media Center Edition’s Windows Media Center recorded television format
• FLV – Flash video (encoded to run in a flash animation)
• MPEG-1 – M1V Video
• MPEG-2 – M2V Video
• NOA – rare movie format use in some Japanese eroges around 2002
• FLA – Adobe Flash (for producing)
• FLR – (text file which contains scripts extracted from SWF by a free ActionScript decompiler named FLARE)
• SOL – Adobe Flash shared object («Flash cookie»)
• STR – Sony PlayStation video stream
• M4V – video container file format developed by Apple
• .mkv – Matroska Matroska is a container format, which enables any video format such as MPEG-4 ASP or AVC to be used along with other content such as subtitles and detailed meta information
• WRAP – MediaForge (*.wrap)
• MNG – mainly simple animation containing PNG and JPEG objects, often somewhat more complex than animated GIF
• .mov – QuickTime container which enables any form of compression to be used; Sorenson codec is the most common; QTCH is the filetype for cached video and audio streams
• .mpeg, .mpg, .mpe — MPEG
• THP – Nintendo proprietary movie/video format
• MPEG-4 – MPEG-4 Part 14, shortened «MP4» multimedia container (most often used for Sony’s PlayStation Portable and Apple’s iPod)
• MXF – Material Exchange Format (standardized wrapper format for audio/visual material developed by SMPTE)
• ROQ – used by Quake III Arena
• NSV – NSV Nullsoft Streaming Video (media container designed for streaming video content over the Internet)
• Ogg – container, multimedia
• RM – RealMedia
• SVI – SVI Samsung video format for portable players
• SMI – SMI SAMI Caption file (HTML like subtitle for movie files)
• .smk – SMK Smacker video file. A video compression system developed by RAD Game Tools
• SWF – Adobe Flash (for viewing)
• WMV – Windows Media Video (See ASF)
• WTV – Windows Vista’s and up Windows Media Center recorded television format
• YUV – raw video format; resolution (horizontal x vertical) and sample structure 4:2:2 or 4:2:0 must be known explicitly
• WebM – video file format for web video using HTML5

Video editing, production[edit]

• BRAW – Blackmagic Design RAW video file name
• DRP – Davinci Resolve 17 project file
• FCP – Final Cut Pro project file
• MSWMM – Windows Movie Maker project file
• PPJ, PRPROJ – Adobe Premiere Pro video editing file
• IMOVIEPROJ – iMovie project file
• VEG, VEG-BAK – Sony Vegas project file
• SUF – Sony camera configuration file (setup.suf) produced by XDCAM-EX camcorders
• WLMP – Windows Live Movie Maker project file
• KDENLIVE – Kdenlive project file
• VPJ – VideoPad project file
• MOTN – Apple Motion project file
• IMOVIEMOBILE – iMovie project file for iOS users
• WFP, WVE — Wondershare Filmora Project
• PDS – Cyberlink PowerDirector project
• VPROJ – VSDC Free Video Editor project file

Video game data[edit]

List of common file formats of data for video games on systems that support filesystems, most commonly PC games.
Minecraft — files used by Mojang to develop Minecraft

• MCADDON – format used by the Bedrock Edition of Minecraft for add-ons; Resource packs for the game
• MCFUNCTION – format used by Minecraft for storing functions
• MCMETA – format used by Minecraft for storing data for customizable texture packs for the game
• MCPACK – format used by the Bedrock Edition of Minecraft for in-game texture packs; full addons for the game
• MCR – format used by Minecraft for storing data for in-game worlds before version 1.2
• MCTEMPLATE – format used by the Bedrock Edition of Minecraft for world templates
• MCWORLD – format used by the Bedrock Edition of Minecraft for in-game worlds
• NBS – format used by Note Block Studio, a tool that can be used to make note block songs for Minecraft.

TrackMania/Maniaplanet Engine – Formats used by games based on the TrackMania engine.

• GBX – All user-created content is stored in this file type.
  • REPLAY.GBX – Stores the replay of a race.
  • CHALLENGE.GBX, MAP.GBX – Stores tracks/maps.
  • SYSTEMCONFIG.GBX – Launcher info.
  • TRACKMANIAVEHICLE.GBX – Info about a certain car type.
  • VEHICLETUNINGS.GBX – Vehicle physics.
  • SOLID.GBX – A block’s model.
  • ITEM.GBX – Custom Maniaplanet item.
  • BLOCK.GBX – Custom Maniaplanet block.
  • TEXTURE.GBX – Info about a texture that are used in materials.
  • MATERIAL.GBX – Info about a material such as surface type that are used in Solids.
  • TMEDCLASSIC.GBX – Block info.
  • GHOST.GBX – Player ghosts in Trackmania and TrackMania Turbo.
  • CONTROLSTYLE.GBX – Menu files.
  • SCORES.GBX – Stores info about the player’s best times.
  • PROFILE.GBX – Stores a player’s info such as their login.
• DDS – Almost every texture in the game uses this format.
• PAK – Stores environment data such as valid blocks.
• LOC – A locator. Locators allow the game to download content such as car skins from an external server.
• SCRIPT.TXT – Scripts for Maniaplanet such as menus and game modes.
• XML – ManiaLinks.

Doom engine – Formats used by games based on the Doom engine.

• DEH – DeHackEd files to mutate the game executable (not officially part of the DOOM engine)
• DSG – Saved game
• LMP – A lump is an entry in a DOOM wad.
• LMP – Saved demo recording
• MUS – Music file (usually contained within a WAD file)
• WAD – Data storage (contains music, maps, and textures)

Quake engine – Formats used by games based on the Quake engine.

• BSP – BSP: (For Binary space partitioning) compiled map format
• MAP – MAP: Raw map format used by editors like GtkRadiant or QuArK
• MDL, MD2, MD3, MD5 – MDL/MD2/MD3/MD5: Model for an item used in the game
• PAK, PK2 – PAK/PK2: Data storage
• PK3, PK4 – PK3/PK4: used by the Quake II, Quake III Arena and Quake 4 game engines, respectively, to store game data, textures etc. They are actually .zip files.
• .dat – not specific file type, often generic extension for «data» files for a variety of applications
  • sometimes used for general data contained within the .PK3/PK4 files
  • .fontdat – a .dat file used for formatting game fonts
• .roq – Video format
• .sav – Savegame format

Unreal Engine – Formats used by games based on the Unreal engine.

• U – Unreal script format
• UAX – Animations format for Unreal Engine 2
• UMX – Map format for Unreal Tournament
• UMX – Music format for Unreal Engine 1
• UNR – Map format for Unreal
• UPK – Package format for cooked content in Unreal Engine 3
• USX – Sound format for Unreal Engine 1 and Unreal Engine 2
• UT2 – Map format for Unreal Tournament 2003 and Unreal Tournament 2004
• UT3 – Map format for Unreal Tournament 3
• UTX – Texture format for Unreal Engine 1 and Unreal Engine 2
• UXX – Cache format; these are files a client downloaded from server (which can be converted to regular formats)

Duke Nukem 3D Engine – Formats used by games based on this engine

• DMO – Save game
• GRP – Data storage
• MAP – Map (usually constructed with BUILD.EXE)

Diablo Engine – Formats used by Diablo by Blizzard Entertainment.

• SV – Save Game
• ITM – Item File

Real Virtuality Engine – Formats used by Bohemia Interactive. Operation:Flashpoint, ARMA 2, VBS2

• SQF – Format used for general editing
• SQM – Format used for mission files
• PBO – Binarized file used for compiled models
• LIP – Format that is created from WAV files to create in-game accurate lip-synch for character animations.

Source Engine – Formats used by Valve. Half-Life 2, Counter-Strike: Source, Day of Defeat: Source, Half-Life 2: Episode One, Team Fortress 2, Half-Life 2: Episode Two, Portal, Left 4 Dead, Left 4 Dead 2, Alien Swarm, Portal 2, Counter-Strike: Global Offensive, Titanfall, Insurgency, Titanfall 2, Day of Infamy

• VMF – Valve Hammer Map editor raw map file
• VMX – Valve Hammer Map editor backup map file
• BSP – Source Engine compiled map file
• MDL – Source Engine model format
• SMD – Source Engine uncompiled model format
• PCF – Source Engine particle effect file
• HL2 – Half-Life 2 save format
• DEM – Source Engine demo format
• VPK – Source Engine pack format
• VTF – Source Engine texture format
• VMT – Source Engine material format.

Pokemon Generation V

• CGB – Pokemon Black and White/Pokemon Black 2 and White 2 C-Gear skins.

Other Formats

• ARC – used to store New Super Mario Bros. Wii level data
• B – used for Grand Theft Auto saved game files
• BOL – used for levels on Poing!PC
• DBPF – The Sims 2, DBPF, Package
• DIVA – Project DIVA timings, element coördinates, MP3 references, notes, animation poses and scores.
• ESM, ESP – Master and Plugin data archives for the Creation Engine
• HAMBU – format used by the Aidan’s Funhouse game RGTW for storing map data^[30]
• HE0, HE2, HE4 – HE games File
• GCF – format used by the Steam content management system for file archives
• IMG – format used by Renderware-based Grand Theft Auto games for data storage
• LOVE – format used by the LOVE2D Engine^[31]
• MAP – format used by Halo: Combat Evolved for archive compression, Doom³, and various other games
• MCA – format used by Minecraft for storing data for in-game worlds^[32]
• NBT – format used by Minecraft for storing program variables along with their (Java) type identifiers
• OEC – format used by OE-Cake for scene data storage
• OSB – osu! storyboard data
• OSC – osu!stream combined stream data
• OSF2 – free osu!stream song file
• OSR – osu! replay data
• OSU – osu! beatmap data
• OSZ2 – paid osu!stream song file
• P3D – format for panda3d by Disney
• PLAGUEINC – format used by Plague Inc. for storing custom scenario information^[33]
• POD – format used by Terminal Reality
• RCT – Used for templates and save files in RollerCoaster Tycoon games
• REP – used by Blizzard Entertainment for scenario replays in StarCraft.
• Simcity, DBPF, .dat, .SC4Lot, .SC4Model – All game plugins use this format, commonly with different file extensions(Simcity 4)
• SMZIP – ZIP-based package for StepMania songs, themes and announcer packs.
• SOLITAIRETHEME8 – A solitaire theme for Windows solitaire
• USLD – format used by Unison Shift to store level layouts.
• VVVVVV – format used by VVVVVV
• CPS – format used by The Powder Toy, Powder Toy save
• STM – format used by The Powder Toy, Powder Toy stamp
• PKG – format used by Bungie for the PC Beta of Destiny 2, for nearly all the game’s assets.
• CHR – format used by Team Salvato, for the character files of Doki Doki Literature Club!
• Z5 – format used by Z-machine for story files in interactive fiction.
• scworld – format used by Survivalcraft to store sandbox worlds.
• scskin – format used by Survivalcraft to store player skins.
• scbtex – format used by Survivalcraft to store block textures.
• prison – format used by Prison Architect to save prisons
• escape – format used by Prison Architect to save escape attempts
• WBFS — (Wii Backup File System)
• .GBA — Game Boy Advance ROM File
• .pss — Sony PlayStation 2 Game Video file and is used to store audio and video data by games for the Playstation 2 console.

Video game storage media[edit]

List of the most common filename extensions used when a game’s ROM image or storage medium is copied from an original read-only memory (ROM) device to an external memory such as hard disk for back up purposes or for making the game playable with an emulator. In the case of cartridge-based software, if the platform specific extension is not used then filename extensions «.rom» or «.bin» are usually used to clarify that the file contains a copy of a content of a ROM. ROM, disk or tape images usually do not consist of one file or ROM, rather an entire file or ROM structure contained within one file on the backup medium.^[34]

• .a26 – Atari 2600
• .a52 – Atari 5200
• .a78 – Atari 7800
• .lnx – Atari Lynx
• .jag, .j64 – Atari Jaguar
• .iso, .wbfs, .wad, .wdf – Wii and WiiU
• .gcm, .iso – GameCube
• .min – Pokemon mini
• .nds – Nintendo DS
• .dsi – Nintendo DSiWare
• .3ds – Nintendo 3DS
• .cia – Nintendo 3DS Installation File (for installing games with the use of the FBI homebrew application)
• .gb – Game Boy (this applies to the original Game Boy and the Game Boy Color)
• .gbc – Game Boy Color
• .gba – Game Boy Advance
• .sav – Game Boy Advance Saved Data Files
• .sgm – Visual Boy Advance Save States
• .n64, .v64, .z64, .u64, .usa, .jap, .pal, .eur, .bin – Nintendo 64
• .pj – Project 64 Save States
• .nes – Nintendo Entertainment System^[35]
• .fds – Famicom Disk System
• .jst – Jnes Save States
• .fc# – FCEUX Save States (.fc#, where # is any character, usually a number)
• .gg – Game Gear
• .sms – Master System
• .sg – SG-1000
• .smd, .bin – Mega Drive/Genesis
• .32x – Sega 32X
• .smc, .078, .sfc – Super NES (.078 is for split ROMs, which are rare)
• .fig – Super Famicom (Japanese releases are rarely .fig, above extensions are more common)
• .srm – Super NES Saved Data Files
• .zst, .zs1-.zs9, .z10-.z99 – ZSNES Save States (.zst, .zs1-.zs9, .z10-.z99)
• .frz, .000-.008 – Snes9X Save States
• .pce – TurboGrafx-16/PC Engine
• .npc, .ngp – Neo Geo Pocket
• .ngc – Neo Geo Pocket Color
• .vb – Virtual Boy
• .int – Intellivision
• .min – Pokémon Mini
• .vec – Vectrex
• .bin – Odyssey²
• .ws – WonderSwan
• .wsc – WonderSwan Color
• .tzx – ZX Spectrum (for exact copies of ZX Spectrum games)
• TAP – for tape images without copy protection
• Z80, SNA – (for snapshots of the emulator RAM)
• DSK – (for disk images)
• .tap – Commodore 64 (.tap) (for tape images including copy protection)
• T64 – (for tape images without copy protection, considerably smaller than .tap files)
• D64 – (for disk images)
• CRT – (for cartridge images)
• .adf – Amiga (.adf) (for 880K diskette images)
• ADZ – GZip-compressed version of the above.
• DMS – Disk Masher System, previously used as a disk-archiving system native to the Amiga, also supported by emulators.
• .pss — A Sony PlayStation 2 Game Video file and is used to store audio and video data by games for the Playstation 2 console.

Virtual machines[edit]

Microsoft Virtual PC, Virtual Server[edit]

• .vfd – Virtual Floppy Disk
• .vhd – Virtual Hard Disk
• .vud – Virtual Undo Disk
• .vmc – Virtual Machine Configuration
• .vsv – Virtual Machine Saved State

VMware ESX, GSX, Workstation, Player[edit]

• .log – Virtual Machine Logfile
• .vmdk, .dsk – Virtual Machine Disk
• .nvram – Virtual Machine BIOS
• .vmem – Virtual Machine paging file
• .vmsd – Virtual Machine snapshot metadata
• .vmsn – Virtual Machine snapshot
• .vmss, .std – Virtual Machine suspended state
• .vmtm – Virtual Machine team data
• .vmx, .cfg – Virtual Machine configuration
• .vmxf – Virtual Machine team configuration

VirtualBox[edit]

• .vdi – VirtualBox virtual disk image
• .vbox-extpack – VirtualBox extension pack

Parallels Workstation[edit]

• .hdd – Virtual Machine hard disk
• .pvs – Virtual Machine preferences/configuration
• .sav – Virtual Machine saved state

QEMU[edit]

• .cow – Copy-on-write
• .qcow – QEMU copy-on-write
• .qcow2 – QEMU copy-on-write – version 2
• .qed – QEMU enhanced disk format

Web page[edit]

Static

• DTD – Document Type Definition (standard), MUST be public and free
• .html, .htm – HTML HyperText Markup Language
• .xhtml, .xht – XHTML eXtensible HyperText Markup Language
• .mht, .mhtml – MHTML Archived HTML, store all data on one web page (text, images, etc.) in one big file
• .maff – MAF web archive based on ZIP

Dynamically generated

• .asp – ASP Microsoft Active Server Page
• .aspx – ASPX Microsoft Active Server Page. NET
• .adp – ADP AOLserver Dynamic Page
• .bml – BML Better Markup Language (templating)
• .cfm – CFM ColdFusion
• .cgi – CGI
• .ihtml – iHTML Inline HTML
• .jsp – JSP JavaServer Pages
• .las, .lasso, .lassoapp – Lasso, A file created or served with the Lasso Programming Language
• .pl – Perl
• .php, .php?, .phtml – PHP ? is version number (previously abbreviated Personal Home Page, later changed to PHP: Hypertext Preprocessor)
• .shtml – SSI HTML with Server Side Includes (Apache)
• .stm – SSI HTML with Server Side Includes (Apache)

Markup languages and other web standards-based formats[edit]

• .atom, .xml – Atom Another syndication format.
• .eml – EML Format used by several desktop email clients.
• .jsonld – JSON-LD A JSON-based serialization for linked data.
• .kprx – KPRX A XML-based serialization for workflow definition generated by K2.
• .ps – PS A XML-based serialization for test automation scripts called PowerScripts for K2 based applications.
• .metalink, .met – Metalink A format to list metadata about downloads, such as mirrors, checksums, and other information.
• .rss, .xml – RSS Syndication format.
• .markdown, .md – Markdown Plain text formatting syntax, which is popularly used to format «readme» files.
• .se – Shuttle Another lightweight markup language.

Other[edit]

• AXD – cookie extensions found in temporary internet folder
• APK — Android Package Kit
• BDF – Binary Data Format – raw data from recovered blocks of unallocated space on a hard drive
• CBP – CD Box Labeler Pro, CentraBuilder, Code::Blocks Project File, Conlab Project
• CEX – SolidWorks Enterprise PDM Vault File
• COL – Nintendo GameCube proprietary collision file (.col)
• CREDX – CredX Dat File
• DDB – Generating code for Vocaloid singers voice (see .DDI)
• DDI – Vocaloid phoneme library (Japanese, English, Korean, Spanish, Chinese, Catalan)
• DUPX – DuupeCheck database management tool project file
• FTM – Family Tree Maker data file
• FTMB – Family Tree Maker backup file
• GA3 – Graphical Analysis 3
• .ged – GEDCOM (GEnealogical Data COMmunication) format to exchange genealogy data between different genealogy software
• HLP – Windows help file
• IGC – flight tracks downloaded from GPS devices in the FAI’s prescribed format
• INF – similar format to INI file; used to install device drivers under Windows, inter alia.
• JAM – JAM Message Base Format for BBSes
• KMC – tests made with KatzReview’s MegaCrammer
• KCL – Nintendo GameCube/Wii proprietary collision file (.kcl)
• KTR – Hitachi Vantara Pentaho Data Integration/Kettle Transformation Project file
• LNK – Microsoft Windows format for Hyperlinks to Executables
• LSM – LSMaker script file (program using layered .jpg to create special effects; specifically designed to render lightsabers from the Star Wars universe) (.lsm)
• NARC – Archive format used in Nintendo DS games.
• OER – AU OER Tool, Open Educational Resource editor
• PA – Used to assign sound effects to materials in KCL files (.pa)
• PIF – Used to run MS-DOS programs under Windows
• POR – So called «portable» SPSS files, readable by PSPP
• PXZ – Compressed file to exchange media elements with PSALMO
• RISE – File containing RISE generated information model evolution
• SCR – Windows Screen Saver file
• TOPC – TopicCrunch SEO Project file holding keywords, domain, and search engine settings (ASCII)
• XLF – Utah State University Extensible LADAR Format
• XMC – Assisted contact lists format, based on XML and used in kindergartens and schools
• ZED – My Heritage Family Tree
• zone – Zone file a text file containing a DNS zone
• FX – Microsoft DirectX plain text effects and properties for the associated file and are used to specify the textures, shading, rendering, lighting and other 3D effects (.fx)
• MIFRAMES – Mine-imator keyframes file (.miframes)
• MILANGUAGE – Mine-Imator language data file (.milanguage)
• MIDATA – Mine-Imator data file (.midata)
• BCA – Short for Burst Cutting Area Holds the information of the circular area near the center of a DVD, HD DVD or Blu-ray Disc, it is usually 64 bytes in size. (.bca)

Cursors[edit]

• ANI – Animated cursor
• CUR – Cursor file
• Smes – Hawk’s Dock configuration file

Generalized files[edit]

General data formats[edit]

These file formats are fairly well defined by long-term use or a general standard, but the content of each file is often highly specific to particular software or has been extended by further standards for specific uses.

Text-based[edit]

• CSV – comma-separated values
• HTML – hyper text markup language
• CSS – cascading style sheets
• INI – a configuration text file whose format is substantially similar between applications
• JSON – JavaScript Object Notation is an openly used data format now used by many languages, not just JavaScript
• TSV – tab-separated values
• XML – an open data format
• YAML – an open data format
• ReStructuredText – an open text format for technical documents used mainly in the Python programming language
• .md – Markdown an open lightweight markup language to create simple but rich text, often used to format README files
• AsciiDoc – an open human-readable markup document format semantically equivalent to DocBook
• .yni — a configuration file similar to YAML

Generic file extensions[edit]

These are filename extensions and broad types reused frequently with differing formats or no specific format by different programs.

Binary files[edit]

• .bak, .bk – Bak file various backup formats: some just copies of data files, some in application-specific data backup formats, some formats for general file backup programs
• BIN – binary data, often memory dumps of executable code or data to be re-used by the same software that originated it
• DAT – data file, usually binary data proprietary to the program that created it, or an MPEG-1 stream of Video CD
• DSK – file representations of various disk storage images
• RAW – raw (unprocessed) data
• SZH — files that are associated with zero unique file types (the most prevalent being the Binary Data format)

Text files[edit]

• .cnf, .conf, .cfg – configuration file substantially software-specific
• .log – logfiles usually text, but sometimes binary
• .asc, .txt – human-readable plain text, usually no more specific

Partial files[edit]

Differences and patches[edit]

• diff – text file differences created by the program diff and applied as updates by patch

Incomplete transfers[edit]

• .!ut – !UT partly complete uTorrent download
• .crdownload – CRDOWNLOAD partly complete Google Chrome download
• .opdownload – OPDOWNLOAD partly complete Opera download
• .part – PART partly complete Mozilla Firefox or Transmission download
• .partial – PARTIAL partly complete Internet Explorer or Microsoft Edge download

Temporary files[edit]

• .temp, .tmp – Temporary file sometimes in a specific format, but often just raw data in the middle of processing
• Pseudo-pipelines, Pseudo-pipeline – Pseudo-pipeline file used to simulate a software pipe

See also[edit]

• List of filename extensions
• MIME#Content-Type, a standard for referring to file formats
• List of motion and gesture file formats
• List of file signatures, or «magic numbers»

References[edit]

External links[edit]

• File formats at Curlie
• File formats at FileInfo.com

From Wikipedia, the free encyclopedia

This is a list of file formats used by computers, organized by type. Filename extension it is usually noted in parentheses if they differ from the file format name or abbreviation. Many operating systems do not limit filenames to one extension shorter than 4 characters, as was common with some operating systems that supported the File Allocation Table (FAT) file system. Examples of operating systems that do not impose this limit include Unix-like systems, and Microsoft Windows NT, 95-98, and ME which have no three character limit on extensions for 32-bit or 64-bit applications on file systems other than pre-Windows 95 and Windows NT 3.5 versions of the FAT file system. Some filenames are given extensions longer than three characters. While MS-DOS and NT always treat the suffix after the last period in a file’s name as its extension, in UNIX-like systems, the final period does not necessarily mean that the text after the last period is the file’s extension.^[1]

Some file formats, such as .txt or .text, may be listed multiple times.

Archive and compressed[edit]

• .?Q? – files that are compressed, often by the SQ program.
• 7z – 7z: 7-Zip compressed file
• A – An external file extension for C/C++
• AAC – Advanced Audio Coding
• ace – ace: ACE compressed file
• ALZ – ALZip compressed file
• APK – Android package: Applications installable on Android; package format of the Alpine Linux distribution
• APPX – Microsoft Application Package (.appx)
• AT3 – Sony’s UMD data compression
• ARC – ARC: pre-Zip data compression
• ARC – Nintendo U8 Archive (mostly Yaz0 compressed)
• ARJ – ARJ compressed file
• ASS, SSA –ASS (also SSA): a subtitles file created by Aegisub, a video typesetting application (also a Halo game engine file)
• B – (B file) Similar to .a, but less compressed.
• BA – BA: Scifer Archive (.ba), Scifer External Archive Type
• BIN – compressed archive, can be read and used by CD-ROMs and Java, extractable by 7-zip and WINRAR
• .bkf – Microsoft backup created by NTBackup.c
• Blend – An external 3D file format used by the animation software, Blender.
• .bz2 – bzip2
• BMP – Bitmap Image – You can create one by right-clicking the home screen, next, click new, then, click Bitmap Image
• cab – A cabinet (.cab) file is a library of compressed files stored as one file. Cabinet files are used to organize installation files that are copied to the user’s system.^[2]
• c4 – JEDMICS image files, a DOD system
• cals – JEDMICS image files, a DOD system
• xaml – Used in programs like Visual Studio to create exe files.
• CPT, SEA – Compact Pro (Macintosh)
• DAA – DAA: Closed-format, Windows-only compressed disk image
• deb – deb: Debian install package
• DMG – an Apple compressed/encrypted format
• DDZ – a file which can only be used by the «daydreamer engine» created by «fever-dreamer», a program similar to RAGS, it’s mainly used to make somewhat short games.
• DN – Adobe Dimension CC file format
• DNG – «Digital Negative» a type of raw image file format used in digital photography.
• DPE – Package of AVE documents made with Aquafadas digital publishing tools.
• .egg – Alzip Egg Edition compressed file
• .egt – EGT Universal Document also used to create compressed cabinet files replaces .ecab
• .ECAB, .ezip – EGT Compressed Folder used in advanced systems to compress entire system folders, replaced by EGT Universal Document
• ESD – ESD: Electronic Software Distribution, a compressed and encrypted WIM File
• .ess – EGT SmartSense File, detects files compressed using the EGT compression system.
• .exe – Windows application
• .flipchart – Used in Promethean ActivInspire Flipchart Software.
• .gbs, .ggp, .gsc – GBS OtterUI binary scene file
• .gho, .ghs – GHO Norton Ghost
• .gif – GIF Graphics Interchange Format
• .gz – gzip Compressed file
• .html – HTML code file
• .ipg – Format in which Apple Inc. packages their iPod games. can be extracted through Winrar
• jar – jar ZIP file with manifest for use with Java applications.
• JPG – Joints Photographic Experts Group – Image File
• JPEG – Joints Photographic Experts Group – Image File
• .Lawrence – LBR Lawrence Compiler Type file
• LBR – LBR Library file
• LQR – LQR LBR Library file compressed by the SQ program.
• .lzh – LHA Lempel, Ziv, Huffman
• .lz – lzip Compressed file
• .lzo – lzo
• lzma – lzma Lempel–Ziv–Markov chain algorithm compressed file
• LZX – LZX
• .lua — Lua
• .mbw – MBRWizard archive
• MHTML – Mime HTML (Hyper-Text Markup Language) code file
• .midi — Musical Instrument Digital Interface
• .mpq – MPQ Archives Used by Blizzard Entertainment
• .bin – BIN MacBinary
• .nl2pkg – NoLimits 2 Package
• .nth – NTH: Nokia Theme Used by Nokia Series 40 Cellphones
• .oar – OAR: OAR archive
• OSG – Compressed osu! live gameplay archive (optimized for spectating)
• OSK – Compressed osu! skin archive
• OSR – Compressed osu! replay archive
• OSZ – Compressed osu! beatmap archive
• PAK – Enhanced type of .ARC archive
• .par, .par2 – PAR Parchive
• .paf – PAF Portable Application File
• .pea – PEA PeaZip archive file
• PNG – Portable Network Graphic Image File
• Webp — Raster image format developed by Google for web graphics
• .php – PHP code file
• .pyk – PYK Compressed file
• .pk3 – PK3 Quake 3 archive (See note on Doom³)
• .pk4 – PK4 Doom³ archive (Opens similarly to a zip archive.)
• .pxz – PXZ A compressed layered image file used for the image editing website, pixlr.com .
• py, pyw – Python code file
• .rar – RAR Rar Archive, for multiple file archive (rar to .r01-.r99 to s01 and so on)
• RAG, RAGS – Game file, a game playable in the RAGS game-engine, a free program which both allows people to create games, and play games, games created have the format «RAG game file»
• RaX – Archive file created by RaX
• RBXL – Roblox Studio place file (XML, binary)
• RBXLX – Roblox Studio place file (exclusively XML)
• RBXM – Roblox Studio model file (XML, binary)
• RBXMX – Roblox Studio model file (exclusively XML)
• RPM – Red Hat package/installer for Fedora, RHEL, and similar systems.
• sb – Scratch file
• sb2 – Scratch 2.0 file
• sb3 – Scratch 3.0 file
• SEN – Scifer Archive (.sen) – Scifer Internal Archive Type
• .sitx – SIT StuffIt (Macintosh)
• SIS, SISX – SIS/SISX: Symbian Application Package
• SKB – Google SketchUp backup File
• .sq – SQ: Squish Compressed Archive
• .srt — SubRip Subtitle — file format for closed captioning or subtitles.
• SWM – Splitted WIM File, usually found on OEM Recovery Partition to store preinstalled Windows image, and to make Recovery backup (to USB Drive) easier (due to FAT32 limitations)
• SZS – Nintendo Yaz0 Compressed Archive
• TAR – TAR: group of files, packaged as one file
• Gzip, .tar.gz – (Gzip, .tar.gz): TGZ gzipped tar file
• .tb – TB Tabbery Virtual Desktop Tab file
• .tib – TIB Acronis True Image backup
• UHA – Ultra High Archive Compression
• .uue – UUE unified utility engine – the generic and default format for all things UUe-related.
• uf2 microsoft makecode arcade game.
• VIV – Archive format used to compress data for several video games, including Need For Speed: High Stakes.
• VOL – video game data package.
• VSA – Altiris Virtual Software Archive
• WAX – Wavexpress – A ZIP alternative optimized for packages containing video, allowing multiple packaged files to be all-or-none delivered with near-instantaneous unpacking via NTFS file system manipulation.
• .wfp a Wondershare Flimora project file
• WIM – WIM A compressed disk image for installing Windows Vista or higher, Windows Fundamentals for Legacy PC, or restoring a system image made from Backup and Restore (Windows Vista/7)
• XAP – Windows Phone Application Package
• xz – xz compressed files, based on LZMA/LZMA2 algorithm
• Z – Unix compress file
• zoo – zoo: based on LZW
• zip – zip: popular compression format
• ZIM – ZIM: an open file format that stores wiki content for offline usage

Physical recordable media archiving[edit]

• ISO – Generic format for most optical media, including CD-ROM, DVD-ROM, Blu-ray, HD DVD and UMD.
• NRG – Proprietary optical media archive format used by Nero applications.
• IMG – Raw disk image, for archiving DOS formatted floppy disks, hard drives, and larger optical media.
• ADF – for archiving Amiga floppy disks
• ADZ – The GZip-compressed version of ADF.
• DMS – a disk-archiving system native to the Amiga.
• DSK – For archiving floppy disks from a number of other platforms, including the ZX Spectrum and Amstrad CPC.
• D64 – An archive of a Commodore 64 floppy disk.
• SDI – used for archiving and providing «virtual disk» functionality.
• MDS – Daemon Tools native disc image format used for making images from optical CD-ROM, DVD-ROM, HD DVD or Blu-ray. It comes together with MDF file and can be mounted with DAEMON Tools.
• MDX – Daemon Tools format that allows getting one MDX disc image file instead of two (MDF and MDS).
• DMG – Macintosh disk image files
• CDI – DiscJuggler image file
• CUE – CDRWrite CUE image file
• CIF – Easy CD Creator .cif format
• C2D – Roxio-WinOnCD .c2d format
• DAA – PowerISO .daa format
• B6T – BlindWrite 6 image file
• B5T – BlindWrite 5 image file
• BWT – BlindWrite 4 image file
• FFPPKG – FreeFire Profile Export Package

LemonOS/LemonTabOS/LemonRoid[edit]

• LEMONAPP – LemonOS/LemonTabOS/LemonRoid App (.lem_app)

Other Extensions[edit]

• HTML – Hypertext Markup Language
• Msi – Windows installation file
• Vdhx – Virtual disk created by Hyper-V (Hyper-V runs on windows operating system)

Computer-aided design[edit]

Computer-aided is a prefix for several categories of tools (e.g., design, manufacture, engineering) which assist professionals in their respective fields (e.g., machining, architecture, schematics).

Computer-aided design (CAD)[edit]

Computer-aided design (CAD) software assists engineers, architects and other design professionals in project design.

• 3DXML – Dassault Systemes graphic representation
• 3MF – Microsoft 3D Manufacturing Format^[3]
• ACP – VA Software VA – Virtual Architecture CAD file
• AMF – Additive Manufacturing File Format
• AEC – DataCAD drawing format^[4]
• AR – Ashlar-Vellum Argon – 3D Modeling
• ART – ArtCAM model
• ASC – BRL-CAD Geometry File (old ASCII format)
• ASM – Solidedge Assembly, Pro/ENGINEER Assembly
• BIN, BIM – Data Design System DDS-CAD
• BREP – Open CASCADE 3D model (shape)
• C3D – C3D Toolkit File Format
• C3P – Construct3 Files
• CCC – CopyCAD Curves
• CCM – CopyCAD Model
• CCS – CopyCAD Session
• CAD – CadStd
• CATDrawing – CATIA V5 Drawing document
• CATPart – CATIA V5 Part document
• CATProduct – CATIA V5 Assembly document
• CATProcess – CATIA V5 Manufacturing document
• cgr – CATIA V5 graphic representation file
• ckd – KeyCreator CAD Modeling
• ckt – KeyCreator CAD Modeling
• CO – Ashlar-Vellum Cobalt – parametric drafting and 3D modeling
• DRW – Caddie Early version of Caddie drawing – Prior to Caddie changing to DWG
• DFT – Solidedge Draft
• DGN – MicroStation design file
• DGK – Delcam Geometry
• DMT – Delcam Machining Triangles
• DXF – ASCII Drawing Interchange file format, AutoCAD
• DWB – VariCAD drawing file
• DWF – Autodesk’s Web Design Format; AutoCAD & Revit can publish to this format; similar in concept to PDF files; Autodesk Design Review is the reader
• DWG – Popular file format for Computer Aided Drafting applications, notably AutoCAD, Open Design Alliance applications, and Autodesk Inventor Drawing files
• EASM – SolidWorks eDrawings assembly file
• EDRW – eDrawings drawing file
• EMB – Wilcom ES Designer Embroidery CAD file
• EPRT – eDrawings part file
• EscPcb – «esCAD pcb» data file by Electro-System (Japan)
• EscSch – «esCAD sch» data file by Electro-System (Japan)
• ESW – AGTEK format
• EXCELLON – Excellon file
• EXP – Drawing Express format
• F3D – Autodesk Fusion 360 archive file^[5]
• FCStd – Native file format of FreeCAD CAD/CAM package
• FM – FeatureCAM Part File
• FMZ – FormZ Project file
• G – BRL-CAD Geometry File
• GBR – Gerber file
• GLM – KernelCAD model
• GRB – T-FLEX CAD File
• GRI – AppliCad GRIM-In file in readable text form for importing roof and wall cladding job data generated by business management and accounting systems into the modelling/estimating program
• GRO – AppliCad GRIM-Out file in readable text form for exporting roof and wall cladding data job material and labour costing data, material lists generated by the modelling/estimating program to business management and accounting systems
• IAM – Autodesk Inventor Assembly file
• ICD – IronCAD 2D CAD file
• IDW – Autodesk Inventor Drawing file
• IFC – buildingSMART for sharing AEC and FM data
• IGES – Initial Graphics Exchange Specification
• .dgn, .cel – Intergraph Standard File Formats Intergraph
• IO – Stud.io 3d model
• IPN – Autodesk Inventor Presentation file
• IPT – Autodesk Inventor Part file
• JT – Jupiter Tesselation
• MCD – Monu-CAD (Monument/Headstone Drawing file)
• MDG – Model of Digital Geometric Kernel
• model – CATIA V4 part document
• OCD – Orienteering Computer Aided Design (OCAD) file
• PAR – Solidedge Part
• PIPE – PIPE-FLO Professional Piping system design file
• PLN – ArchiCad project
• PRT – NX (recently known as Unigraphics), Pro/ENGINEER Part, CADKEY Part
• PSM – Solidedge Sheet
• PSMODEL – PowerSHAPE Model
• PWI – PowerINSPECT File
• PYT – Pythagoras File
• SKP – SketchUp Model
• RLF – ArtCAM Relief
• RVM – AVEVA PDMS 3D Review model
• RVT – Autodesk Revit project files
• RFA – Autodesk Revit family files
• RXF – AppliCad annotated 3D roof and wall geometry data in readable text form used to exchange 3D model geometry with other systems such as truss design software
• S12 – Spirit file, by Softtech
• SCAD – OpenSCAD 3D part model
• SCDOC – SpaceClaim 3D Part/Assembly
• SLDASM – SolidWorks Assembly drawing
• SLDDRW – SolidWorks 2D drawing
• SLDPRT – SolidWorks 3D part model
• dotXSI – For Softimage
• STEP – Standard for the Exchange of Product model data
• STL – Stereo Lithographic data format used by various CAD systems and stereo lithographic printing machines.
• STD – Power Vision Plus – Electricity Meter Data (Circutor)
• TCT – TurboCAD drawing template
• TCW – TurboCAD for Windows 2D and 3D drawing
• UNV – I-DEAS I-DEAS (Integrated Design and Engineering Analysis Software)
• VC6 – Ashlar-Vellum Graphite – 2D and 3D drafting
• VLM – Ashlar-Vellum Vellum, Vellum 2D, Vellum Draft, Vellum 3D, DrawingBoard
• VS – Ashlar-Vellum Vellum Solids
• WRL – Similar to STL, but includes color. Used by various CAD systems and 3D printing rapid prototyping machines. Also used for VRML models on the web.
• X_B – Parasolids binary format
• X_T – Parasolids
• XE – Ashlar-Vellum Xenon – for associative 3D modeling
• ZOFZPROJ – ZofzPCB 3D PCB model, containing mesh, netlist and BOM

Electronic design automation (EDA)[edit]

Electronic design automation (EDA), or electronic computer-aided design (ECAD), is specific to the field of electrical engineering.

• BRD – Board file for EAGLE Layout Editor, a commercial PCB design tool
• BSDL – Description language for testing through JTAG
• CDL – Transistor-level netlist format for IC design
• CPF – Power-domain specification in system-on-a-chip (SoC) implementation (see also UPF)
• DEF – Gate-level layout
• DSPF – Detailed Standard Parasitic Format, Analog-level parasitics of interconnections in IC design
• EDIF – Vendor neutral gate-level netlist format
• FSDB – Analog waveform format (see also Waveform viewer)
• GDSII – Format for PCB and layout of integrated circuits
• HEX – ASCII-coded binary format for memory dumps
• LEF – Library Exchange Format, physical abstract of cells for IC design
• LIB – Library modeling (function, timing) format
• MS12 – NI Multisim file
• OASIS – Open Artwork System Interchange Standard
• OpenAccess – Design database format with APIs
• PSF – Cadence proprietary format to store simulation results/waveforms (2GB limit)
• PSFXL – Cadence proprietary format to store simulation results/waveforms
• SDC – Synopsys Design Constraints, format for synthesis constraints
• SDF – Standard for gate-level timings
• SPEF – Standard format for parasitics of interconnections in IC design
• SPI, CIR – SPICE Netlist, device-level netlist and commands for simulation
• SREC, S19 – S-record, ASCII-coded format for memory dumps
• SST2 – Cadence proprietary format to store mixed-signal simulation results/waveforms
• STIL – Standard Test Interface Language, IEEE1450-1999 standard for Test Patterns for IC
• SV – SystemVerilog source file
• S*P – Touchstone/EEsof Scattering parameter data file – multi-port blackbox performance, measurement or simulated
• TLF – Contains timing and logical information about a collection of cells (circuit elements)
• UPF – Standard for Power-domain specification in SoC implementation
• V – Verilog source file
• VCD – Standard format for digital simulation waveform
• VHD, VHDL – VHDL source file
• WGL – Waveform Generation Language, format for Test Patterns for IC

Test technology[edit]

Files output from Automatic Test Equipment or post-processed from such.

• Standard Test Data Format

Database[edit]

• 4DB – 4D database Structure file
• 4DD – 4D database Data file
• 4DIndy – 4D database Structure Index file
• 4DIndx – 4D database Data Index file
• 4DR – 4D database Data resource file (in old 4D versions)
• ACCDB – Microsoft Database (Microsoft Office Access 2007 and later)
• ACCDE – Compiled Microsoft Database (Microsoft Office Access 2007 and later)
• ADT – Sybase Advantage Database Server (ADS)
• APR – Lotus Approach data entry & reports
• BOX – Lotus Notes Post Office mail routing database
• CHML – Krasbit Technologies Encrypted database file for 1 click integration between contact management software and the chameleon(tm) line of imaging workflow solutions
• DAF – Digital Anchor data file
• DAT – DOS Basic
• DAT – Intersystems Caché database file
• DB – Paradox
• DB – SQLite
• DBF – db/dbase II,III,IV and V, Clipper, Harbour/xHarbour, Fox/FoxPro, Oracle
• DTA – Sage Sterling database file
• EGT – EGT Universal Document, used to compress sql databases to smaller files, may contain original EGT database style.
• ESS – EGT SmartSense is a database of files and its compression style. Specific to EGT SmartSense
• EAP – Enterprise Architect Project
• FDB – Firebird Databases
• FDB – Navision database file
• FP, FP3, FP5, FP7 – FileMaker Pro
• FRM – MySQL table definition
• GDB – Borland InterBase Databases
• GTABLE – Google Drive Fusion Table
• KEXI – Kexi database file (SQLite-based)
• KEXIC – shortcut to a database connection for a Kexi databases on a server
• KEXIS – shortcut to a Kexi database
• LDB – Temporary database file, only existing when database is open
• LIRS – Layered Intager Storage. Stores intageres with characters such as semicolons to create lists of data.
• MDA – Add-in file for Microsoft Access
• MDB – Microsoft Access database
• ADP – Microsoft Access project (used for accessing databases on a server)
• MDE – Compiled Microsoft Database (Access)
• MDF – Microsoft SQL Server Database
• MYD – MySQL MyISAM table data
• MYI – MySQL MyISAM table index
• NCF – Lotus Notes configuration file
• NSF – Lotus Notes database
• NTF – Lotus Notes database design template
• NV2 – QW Page NewViews object oriented accounting database
• ODB – LibreOffice Base or OpenOffice Base database
• ORA – Oracle tablespace files sometimes get this extension (also used for configuration files)
• PCONTACT – WinIM Contact file
• PDB – Palm OS Database
• PDI – Portable Database Image
• PDX – Corel Paradox database management
• PRC – Palm OS resource database
• SQL – bundled SQL queries
• REC – GNU recutils database
• REL – Sage Retrieve 4GL data file
• RIN – Sage Retrieve 4GL index file
• SDB – StarOffice’s StarBase
• SDF – SQL Compact Database file
• sqlite – SQLite
• UDL – Universal Data Link
• waData – Wakanda (software) database Data file
• waIndx – Wakanda (software) database Index file
• waModel – Wakanda (software) database Model file
• waJournal – Wakanda (software) database Journal file
• WDB – Microsoft Works Database
• WMDB – Windows Media Database file – The CurrentDatabase_360.wmdb file can contain file name, file properties, music, video, photo and playlist information.

Big Data (Distributed)[edit]

• Avro – Data format appropriate for ingestion of record based attributes. Distinguishing characteristic is schema is stored on each row enabling schema evolution.
• Parquet – Columnar data storage. It is typically used within the Hadoop ecosystem.
• ORC – Similar to Parquet, but has better data compression and schema evolution handling.

Desktop publishing[edit]

• AI – Adobe Illustrator
• AVE, ZAVE – Aquafadas
• CDR – CorelDRAW
• CHP, pub, STY, CAP, CIF, VGR, FRM – Ventura Publisher – Xerox (DOS / GEM)
• CPT – Corel Photo-Paint
• DTP – Greenstreet Publisher, GST PressWorks
• FM – Adobe FrameMaker
• GDRAW – Google Drive Drawing
• ILDOC – Broadvision Quicksilver document
• INDD – Adobe InDesign
• MCF – FotoInsight Designer
• PDF – Adobe Acrobat or Adobe Reader
• PMD – Adobe PageMaker
• PPP – Serif PagePlus
• PSD – Adobe Photoshop
• PUB – Microsoft Publisher
• QXD – QuarkXPress
• SLA, SCD – Scribus
• XCF – XCF: File format used by the GIMP, as well as other programs

Document[edit]

These files store formatted text and plain text.

• 0 – Plain Text Document, normally used for licensing
• 1ST – Plain Text Document, normally preceded by the words «README» (README.1ST)
• 600 – Plain Text Document, used in UNZIP history log
• 602 – Text602 (T602) document
• ABW – AbiWord document
• ACL – MS Word AutoCorrect List
• AFP – Advanced Function Presentation
• AMI – Lotus Ami Pro Amigaguide
• ANS – American National Standards Institute (ANSI) text
• ASC – ASCII text
• AWW – Ability Write
• CCF – Color Chat 1.0
• CSV – ASCII text as comma-separated values, used in spreadsheets and database management systems
• CWK – ClarisWorks-AppleWorks document
• DBK – DocBook XML sub-format
• DITA – Darwin Information Typing Architecture document
• DOC – Microsoft Word document
• DOCM – Microsoft Word macro-enabled document
• DOCX – Office Open XML document
• DOT – Microsoft Word document template
• DOTX – Office Open XML text document template
• DWD – DavkaWriter Heb/Eng word processor file
• EGT – EGT Universal Document
• EPUB – EPUB open standard for e-books
• EZW – Reagency Systems easyOFFER document^[6]
• FDX – Final Draft
• FTM – Fielded Text Meta
• FTX – Fielded Text (Declared)
• GDOC – Google Drive Document
• HTML – HyperText Markup Language (.html, .htm)
• HWP – Haansoft (Hancom) Hangul Word Processor document
• HWPML – Haansoft (Hancom) Hangul Word Processor Markup Language document
• LOG – Text log file
• LWP – Lotus Word Pro
• MBP – metadata for Mobipocket documents
• MD – Markdown text document
• ME – Plain text document normally preceded by the word «READ» (READ.ME)
• MCW – Microsoft Word for Macintosh (versions 4.0–5.1)
• Mobi – Mobipocket documents
• NB – Mathematica Notebook
• nb – Nota Bene Document (Academic Writing Software)
• NBP – Mathematica Player Notebook
• NEIS – 학교생활기록부 작성 프로그램 (Student Record Writing Program) Document
• NT – N-Triples RDF container (.nt)
• NQ – N-Quads RDF container (.nq)
• ODM – OpenDocument master document
• ODOC – Synology Drive Office Document
• ODT – OpenDocument text document
• OSHEET – Synology Drive Office Spreadsheet
• OTT – OpenDocument text document template
• OMM – OmmWriter text document
• PAGES – Apple Pages document
• PAP – Papyrus word processor document
• PER — Canadian Forces Personnel Appraisal System (CFPAS) Personnel Evaluation Report (PER)
• PDR — Canadian Forces Personnel Appraisal System (CFPAS) Personnel Development Report (PDR)
• PDAX – Portable Document Archive (PDA) document index file
• PDF – Portable Document Format
• QUOX – Question Object File Format for Quobject Designer or Quobject Explorer
• Radix-64 – Need helps!!!
• RTF – Rich Text document
• RPT – Crystal Reports
• SDW – StarWriter text document, used in earlier versions of StarOffice
• SE – Shuttle Document
• STW – OpenOffice.org XML (obsolete) text document template
• Sxw – OpenOffice.org XML (obsolete) text document
• TeX – TeX
• INFO – Texinfo
• Troff – Unix OS document processing system
• TXT – ASCII or Unicode plain text file
• UOF – Uniform Office Format
• UOML – Unique Object Markup Language
• VIA – Revoware VIA Document Project File
• WPD – WordPerfect document
• WPS – Microsoft Works document
• WPT – Microsoft Works document template
• WRD – WordIt! document
• WRF – ThinkFree Write
• WRI – Microsoft Write document
• xhtml, xht – XHTML eXtensible HyperText Markup Language
• XML – eXtensible Markup Language
• XPS – XPS: Open XML Paper Specification

Financial records[edit]

• MYO – MYOB Limited (Windows) File
• MYOB – MYOB Limited (Mac) File
• TAX – TurboTax File
• YNAB – You Need a Budget (YNAB) File

Financial data transfer formats[edit]

• IFX – Interactive Financial Exchange XML-based specification for various forms of financial transactions
• .ofx – Open Financial Exchange， open standard supported by CheckFree and Microsoft and partly by Intuit; SGML and later XML based
• QFX – proprietary pay-only format used only by Intuit
• .qif – Quicken Interchange Format open standard formerly supported by Intuit

Font file[edit]

• ABF – Adobe Binary Screen Font
• AFM – Adobe Font Metrics
• BDF – Bitmap Distribution Format
• BMF – ByteMap Font Format
• BRFNT – Binary Revolution Font Format
• FNT – Bitmapped Font – Graphics Environment Manager (GEM)
• FON – Bitmapped Font – Microsoft Windows
• MGF – MicroGrafx Font
• OTF – OpenType Font
• PCF – Portable Compiled Format
• PFA – Printer Font ASCII
• PFB – Printer Font Binary – Adobe
• PFM – Printer Font Metrics – Adobe
• AFM – Adobe Font Metrics
• FOND – Font Description resource – Mac OS
• SFD – FontForge spline font database Font
• SNF – Server Normal Format
• TDF – TheDraw Font
• TFM – TeX font metric
• .ttf, .ttc – TrueType Font
• UFO – Unified Font Object is a cross-platform, cross-application, human readable, future proof format for storing font data.
• WOFF – Web Open Font Format

General purpose[edit]

These file formats allow for the rapid creation of new binary file formats.

• IFDS — Incredibly Flexible Data Storage file format. File extension and the magic number does not have to be IFDS.^[7]

Geographic information system[edit]

• ASC – ASCII point of interest (POI) text file
• APR – ESRI ArcView 3.3 and earlier project file
• DEM – USGS DEM file format
• E00 – ARC/INFO interchange file format
• GeoJSON –Geographically located data in object notation
• GeoTIFF – Geographically located raster data
• GML – Geography Markup Language file^[8]
• GPX – XML-based interchange format
• ITN – TomTom Itinerary format
• MXD – ESRI ArcGIS project file, 8.0 and higher
• NTF – National Transfer Format file
• OV2 – TomTom POI overlay file
• SHP – ESRI shapefile
• TAB – MapInfo Table file format
• GeoTIFF – Geographically located raster data: text file giving corner coordinate, raster cells per unit, and rotation
• DTED – Digital Terrain Elevation Data
• KML – Keyhole Markup Language, XML-based

Graphical information organizers[edit]

• 3DT – 3D Topicscape, the database in which the meta-data of a 3D Topicscape is held, it is a form of 3D concept map (like a 3D mind-map) used to organize ideas, information, and computer files
• ATY – 3D Topicscape file, produced when an association type is exported; used to permit round-trip (export Topicscape, change files and folders as desired, re-import to 3D Topicscape)
• CAG – Linear Reference System
• FES – 3D Topicscape file, produced when a fileless occurrence in 3D Topicscape is exported to Windows. Used to permit round-trip (export Topicscape, change files and folders as desired, re-import them to 3D Topicscape)
• MGMF – MindGenius Mind Mapping Software file format
• MM – FreeMind mind map file (XML)
• MMP – Mind Manager mind map file
• TPC – 3D Topicscape file, produced when an inter-Topicscape topic link file is exported to Windows; used to permit round-trip (export Topicscape, change files and folders as desired, re-import to 3D Topicscape)

Graphics[edit]

Color palettes[edit]

• ACT – Adobe Color Table. Contains a raw color palette and consists of 256 24-bit RGB colour values.
• ASE – Adobe Swatch Exchange. Used by Adobe Photoshop, Illustrator, and InDesign.^[9]
• GPL – GIMP palette file. Uses a text representation of color names and RGB values. Various open source graphical editors can read this format,^[10] including GIMP, Inkscape, Krita,^[11] KolourPaint, Scribus, CinePaint, and MyPaint.^[12]
• PAL – Microsoft RIFF palette file

Color management[edit]

• ICC, ICM – Color profile conforming the specification of the ICC.

Raster graphics[edit]

Raster or bitmap files store images as a group of pixels.

Vector graphics[edit]

Vector graphics use geometric primitives such as points, lines, curves, and polygons to represent images.

• 3DS — 3D vector graphic file read by the Nintendo 3DS
• 3DV – 3-D wireframe graphics by Oscar Garcia
• AMF – Additive Manufacturing File Format
• AWG – Ability Draw
• AI – Adobe Illustrator Document
• CGM – Computer Graphics Metafile, an ISO Standard
• CDR – CorelDRAW Document
• CMX – CorelDRAW vector image
• DP – Drawing Program file for PERQ^[13]
• DRAWIO – Diagrams.net offline diagram
• DXF – ASCII Drawing Interchange file Format, used in AutoCAD and other CAD-programs
• E2D – 2-dimensional vector graphics used by the editor which is included in JFire
• EGT – EGT Universal Document, EGT Vector Draw images are used to draw vector to a website
• EPS – Encapsulated Postscript
• FS – FlexiPro file
• GBR – Gerber file
• ODG – OpenDocument Drawing
• MOVIE.BYU – 3D Vector file for polygons, coordinates and more complex shapes
• RenderMan – Displays Shading in both 2D and 3D scapes
• SVG – Scalable Vector Graphics, employs XML
• 3DMLW – Scene description languages (3D vector image formats)
• STL – STL: Stereo Lithographic data format (see STL (file format)) used by various CAD systems and stereo lithographic printing machines. See above.
• .wrl – Virtual Reality Modeling Language, VRML Uses this extension for the creation of 3D viewable web images.
• X3D – XML based file for communicating 3D graphics
• SXD – OpenOffice.org XML (obsolete) Drawing
• TGAX – Texture format used by Zwift
• V2D – voucher design used by the voucher management included in JFire
• VDOC – Vector format used in AnyCut, CutStorm, DrawCut, DragonCut, FutureDRAW, MasterCut, SignMaster, VinylMaster software by Future Corporation
• VSD – Vector format used by Microsoft Visio
• VSDX – Vector format used by MS Visio and opened by VSDX Annotator
• VND – Vision numeric Drawing file used in TypeEdit, Gravostyle.
• WMF – WMF: Windows Meta File
• EMF – EMF: Enhanced (Windows) MetaFile, an extension to WMF
• ART – Xara–Drawing (superseded by XAR)
• XAR – Xara–Drawing

3D graphics[edit]

3D graphics are 3D models that allow building models in real-time or non-real-time 3D rendering.

• 3DMF – QuickDraw 3D Metafile (.3dmf)
• 3DM – OpenNURBS Initiative 3D Model (used by Rhinoceros 3D) (.3dm)
• 3MF – Microsoft 3D Manufacturing Format (.3mf)^[3]
• 3DS – legacy 3D Studio Model (.3ds)
• ABC – Alembic (computer graphics)
• AC – AC3D Model (.ac)
• AMF – Additive Manufacturing File Format
• AN8 – Anim8or Model (.an8)
• AOI – Art of Illusion Model (.aoi)
• ASM – PTC Creo assembly (.asm)
• B3D – Blitz3D Model (.b3d)
• BLEND – Blender (.blend)
• BLOCK – Blender encrypted blend files (.block)
• BMD3 – Nintendo GameCube first-party J3D proprietary model format (.bmd)
• BDL4 – Nintendo GameCube and Wii first-party J3D proprietary model format (2002, 2006–2010) (.bdl)
• BRRES – Nintendo Wii first-party proprietary model format 2010+ (.brres)
• BFRES – Nintendo Wii U and later Switch first-party proprietary model format
• C4D – Cinema 4D (.c4d)
• Cal3D – Cal3D (.cal3d)
• CCP4 – X-ray crystallography voxels (electron density)
• CFL – Compressed File Library (.cfl)
• COB – Caligari Object (.cob)
• CORE3D – Coreona 3D Coreona 3D Virtual File(.core3d)
• CTM – OpenCTM (.ctm)
• DAE – COLLADA (.dae)
• DFF – RenderWare binary stream, commonly used by Grand Theft Auto III-era games as well as other RenderWare titles
• DPM – deepMesh (.dpm)
• DTS – Torque Game Engine (.dts)
• EGG – Panda3D Engine
• FACT – Electric Image (.fac)
• FBX – Autodesk FBX (.fbx)
• G – BRL-CAD geometry (.g)
• GLB – a binary form of glTF required to be loaded in Facebook 3D Posts. (.glb)
• GLM – Ghoul Mesh (.glm)
• glTF – the JSON-based standard developed by Khronos Group (.gltf)
• .hec – Hector Game Engine – Flatspace model format
• IO – Bricklink Stud.io 2.0 Model File (.io)
• IOB – Imagine (3D modeling software) (.iob)
• JAS – Cheetah 3D file (.jas)
• JMESH – Universal mesh data exchange file based on JMesh specification (.jmsh for text/JSON based, .bmsh for binary/UBJSON based)
• LDR – LDraw Model File (.ldr)
• LWO – Lightwave Object (.lwo)
• LWS – Lightwave Scene (.lws)
• LXF – LEGO Digital Designer Model file (.lxf)
• LXO – Luxology Modo (software) file (.lxo)
• M3D – Model3D, universal, engine-neutral format (.m3d)
• MA – Autodesk Maya ASCII File (.ma)
• MAX – Autodesk 3D Studio Max file (.max)
• MB – Autodesk Maya Binary File (.mb)
• MPD – LDraw Multi-Part Document Model File (.mpd)
• MD2 – MD2: Quake 2 model format (.md2)
• MD3 – MD3: Quake 3 model format (.md3)
• MD5 – MD5: Doom 3 model format (.md5)
• MDX – Blizzard Entertainment’s own model format (.mdx)
• MESH – New York University(.m)
• MESH – Meshwork Model (.mesh)
• MIOBJECT – Mine-Imator object file (.miobject)
• MIPARTICLE – Mine-Imator particle file (.miparticle)
• MIMODEL – Mine-Imator model file (.mimodel)
• MM3D – Misfit Model 3d (.mm3d)
• MPO – Multi-Picture Object – This JPEG standard is used for 3d images, as with the Nintendo 3DS
• MRC – MRC: voxels in cryo-electron microscopy
• NIF – Gamebryo NetImmerse File (.nif)
• OBJ – Wavefront .obj file (.obj)
• OFF – OFF Object file format (.off)
• OGEX – Open Game Engine Exchange (OpenGEX) format (.ogex)
• PLY – PLY: Polygon File Format / Stanford Triangle Format (.ply)
• PRC – Adobe PRC (embedded in PDF files)
• PRT – PTC Creo part (.prt)
• POV – POV-Ray document (.pov)
• R3D – Realsoft 3D (Real-3D) (.r3d)
• RWX – RenderWare Object (.rwx)
• SIA – Nevercenter Silo Object (.sia)
• SIB – Nevercenter Silo Object (.sib)
• SKP – Google Sketchup file (.skp)
• SLDASM – SolidWorks Assembly Document (.sldasm)
• SLDPRT – SolidWorks Part Document (.sldprt)
• SMD – Valve Studiomdl Data format (.smd)
• U3D – Universal 3D format (.u3d)
• USD – Universal Scene Description (.usd)
• USDA – Universal Scene Description , Human-readable text format (.usda)
• USDC – Universal Scene Description , Binary format (.usdc)
• USDZ – Universal Scene Description Zip (.usdz)
• VIM – Revizto visual information model format (.vimproj)
• VRML97 – VRML Virtual reality modeling language (.wrl)
• VUE – Vue scene file (.vue)
• VWX – Vectorworks (.vwx)
• WINGS – Wings3D (.wings)
• W3D – Westwood 3D Model (.w3d)
• X – DirectX 3D Model (.x)
• X3D – Extensible 3D (.x3d)
• Z3D – Zmodeler (.z3d)
• ZBMX – Mecabricks Blender Add-On (.zbmx)

Links and shortcuts[edit]

• Alias – Alias (Mac OS)
• JNLP – Java Network Launching Protocol, an XML file used by Java Web Start for starting Java applets over the Internet
• LNK – binary-format file shortcut in Microsoft Windows 95 and later
• APPREF-MS – File shortcut format used by ClickOnce
• NAL – ZENworks Instant shortcut (opens a .EXE not on the C:/ )
• URL – INI file pointing to a URL bookmarks/Internet shortcut in Microsoft Windows
• WEBLOC – Property list file pointing to a URL bookmarks/Internet shortcut in macOS
• SYM – Symbolic link
• .desktop – Desktop entry on Linux Desktop environments

Mathematical[edit]

• Harwell-Boeing – a file format designed to store sparse matrices
• MML – MathML – Mathematical Markup Language
• ODF – OpenDocument Math Formula
• SXM – OpenOffice.org XML (obsolete) Math Formula

Object code, executable files, shared and dynamically linked libraries[edit]

• 8BF – files plugins for some photo editing programs including Adobe Photoshop, Paint Shop Pro, GIMP and Helicon Filter.
• .a — a static library on on Unix-like systems
• .a – Objective C native static library
• a.out – (no suffix for executable image, .o for object files, .so for shared object files) classic UNIX object format, now often superseded by ELF
• APK – Android Application Package
• APP – A folder found on macOS systems containing program code and resources, appearing as one file.
• BAC – an executable image for the RSTS/E system, created using the BASIC-PLUS COMPILE command^[14]
• BPL – a Win32 PE file created with Borland Delphi or C++Builder containing a package.
• Bundle – a Macintosh plugin created with Xcode or make which holds executable code, data files, and folders for that code.
• .class – Compiled Java bytecode
• COFF – (no suffix for executable image, .o for object files) UNIX Common Object File Format, now often superseded by ELF
• COM – Simple executable format used by CP/M and DOS.
• DCU – Delphi compiled unit
• DLL – Dynamic library used in Windows and OS/2 to store data, resources and code.
• DOL – the format used by the GameCube and Wii, short for Dolphin, which was the codename of the GameCube.
• .EAR – archives of Java enterprise applications
• ELF – (no suffix for executable image, .o for object files, .so for shared object files) used in many modern Unix and Unix-like systems, including Solaris, other System V Release 4 derivatives, Linux, and BSD)
• .exe – DOS executable (.exe: used in DOS)
• .EXE – New Executable (used in multitasking («European») MS-DOS 4.0, 16-bit Microsoft Windows, and OS/2)
• .EXE – Portable Executable used in Microsoft Windows and some other systems
• .ipa, .IPA – file extension for apple IOS application executable file. Another form of zip file.
• .JAR – archives of Java class files
• JEFF – a file format allowing execution directly from static memory^[15]
• .ko — Loadable kernel module
• LIB — a static library on Microsoft platforms
• LIST – variable list
• Mach-O – (no suffix for executable image, .o for object files, .dylib and .bundle for shared object files) Mach-based systems, notably native format of macOS, iOS, watchOS, and tvOS
• .NLM – NetWare Loadable Module the native 32-bit binaries compiled for Novell’s NetWare Operating System (versions 3 and newer)
• .o – un-linked object files directly from the compiler
• OBJ — object file on Windows
• RLL – used in Microsoft operating systems together with a DLL file to store program resources
• .s1es – Executable used for S1ES learning system.
• .so – shared library, typically ELF
• .VAP – Value Added Process the native 16-bit binaries compiled for Novell’s NetWare Operating System (version 2, NetWare 286, Advanced NetWare, etc.)
• WAR, .WAR – .WAR are archives of Java Web applications
• .XAP – Windows Phone package
• XBE – XBE is Xbox executable
• XCOFF – (no suffix for executable image, .o for object files, .a for shared object files) extended COFF, used in AIX
• XEX – XEX is Xbox 360 executable
• .XPI – PKZIP archive that can be run by Mozilla web browsers to install software.

Object extensions:

• .OCX – .OCX are Object Control extensions
• .TLB – .TLB are Windows Type Library
• .VBX – .VBX are Visual Basic extensions

Page description language[edit]

• DVI – DVI are Device independent format
• .egt – Universal Document can be used to store CSS type styles
• PLD – PLD (Need to be added!!!)
• PCL – PCL (Need to be added!!!)
• PDF – PDF are Portable Document Format
• .ps, .ps, .gz – PostScript (Need to be added!!!)
• SNP – SNP are Microsoft Access Report Snapshot
• XPS – XPS
• XSL-FO – XSL-FO (Formatting Objects)
• Configurations, Metadata
  • CSS – CSS are Cascading Style Sheets
  • .xslt, .xsl – XML Style Sheet
  • .tpl – Web template

Personal information manager[edit]

• MNB — MyInfo notebook
• MSG – Microsoft Outlook task manager
• ORG – Lotus Organizer PIM package
• ORG – Emacs Org-Mode Mindmanager, contacts, calendar, email-integration
• PST, OST – Microsoft Outlook email communication
• SC2 – Microsoft Schedule+ calendar

Presentation[edit]

• GSLIDES – Google Drive Presentation
• KEY, KEYNOTE – Apple Keynote Presentation
• NB – Mathematica Slideshow
• NBP – Mathematica Player slideshow
• ODP – OpenDocument Presentation
• OTP – OpenDocument Presentation template
• PEZ – Prezi Desktop Presentation
• POT – Microsoft PowerPoint template
• PPS – Microsoft PowerPoint Show
• PPT – Microsoft PowerPoint Presentation
• PPTX – Office Open XML Presentation
• PRZ – Lotus Freelance Graphics
• SDD – StarOffice’s StarImpress
• SHF – ThinkFree Show
• SHOW – Haansoft(Hancom) Presentation software document
• SHW – Corel Presentations slide show creation
• SLP – Logix-4D Manager Show Control Project
• SSPSS – SongShow Plus Slide Show
• STI – OpenOffice.org XML (obsolete) Presentation template
• SXI – OpenOffice.org XML (obsolete) Presentation
• THMX – Microsoft PowerPoint theme template
• WATCH – Dataton Watchout Presentation

Project management software[edit]

• MPP – Microsoft Project

Reference management software[edit]

Formats of files used for bibliographic information (citation) management.

• bib – BibTeX
• enl – EndNote
• ris – Research Information Systems RIS (file format)

Scientific data (data exchange)[edit]

• .fits – FITS (Flexible Image Transport System) standard data format for astronomy
• Silo – Silo, a storage format for visualization developed at Lawrence Livermore National Laboratory
• SPC – SPC, spectroscopic data
• EAS3 – binary format for structured data
• EOSSA – Electro-Optic Space Situational Awareness format
• OST – (Open Spatio-Temporal) extensible, mainly images with related data, or just pure data; meant as an open alternative for microscope images
• CCP4 – CCP4, X-ray crystallography voxels (electron density)
• MRC – MRC, voxels in cryo-electron microscopy
• HITRAN – spectroscopic data with one optical/infrared transition per line in the ASCII file (.hit)
• .root – hierarchical platform-independent compressed binary format used by ROOT
• SDF – Simple Data Format (SDF), a platform-independent, precision-preserving binary data I/O format capable of handling large, multi-dimensional arrays.
• MYD – Everfine LEDSpec software file for LED measurements
• CSDM – (Core Scientific Dataset Model) model for multi-dimensional and correlated datasets from various spectroscopies, diffraction, microscopy, and imaging techniques (.csdf, .csdfe).^[16]

Multi-domain[edit]

• NetCDF – Network common data format
• HDR, HDF, h4, h5 – Hierarchical Data Format
• SDXF – SDXF, (Structured Data Exchange Format)
• CDF – Common Data Format
• CGNS – CGNS, CFD General Notation System
• FMF – Full-Metadata Format

Meteorology[edit]

• GRIB – Grid in Binary, WMO format for weather model data
• BUFR – WMO format for weather observation data
• PP – UK Met Office format for weather model data
• NASA-Ames – Simple text format for observation data. First used in aircraft studies of the atmosphere.

Chemistry[edit]

• CML – Chemical Markup Language (CML) (.cml)
• .mol, .sd, .sdf – Chemical table file (CTab)
• .dx, .jdx – Joint Committee on Atomic and Molecular Physical Data (JCAMP)
• .smi – Simplified molecular input line entry specification (SMILES)

Mathematics[edit]

• .g6, .s6 – graph6, sparse6, ASCII encoding of Adjacency matrices

Biology[edit]

Molecular biology and bioinformatics:

• AB1 – In DNA sequencing, chromatogram files used by instruments from Applied Biosystems
• ACE – A sequence assembly format
• ASN.1 – Abstract Syntax Notation One, is an International Standards Organization (ISO) data representation format used to achieve interoperability between platforms. NCBI uses ASN.1 for the storage and retrieval of data such as nucleotide and protein sequences, structures, genomes, and PubMed records.
• BAM – Binary Alignment/Map format (compressed SAM format)
• BCF – Binary compressed VCF format
• BED – The browser extensible display format is used for describing genes and other features of DNA sequences
• CAF – Common Assembly Format for sequence assembly
• CRAM – compressed file format for storing biological sequences aligned to a reference sequence
• DDBJ – The flatfile format used by the DDBJ to represent database records for nucleotide and peptide sequences from DDBJ databases.
• EMBL – The flatfile format used by the EMBL to represent database records for nucleotide and peptide sequences from EMBL databases.
• FASTA – The FASTA format, for sequence data. Sometimes also given as FNA or FAA (Fasta Nucleic Acid or Fasta Amino Acid).
• FASTQ – The FASTQ format, for sequence data with quality. Sometimes also given as QUAL.
• GCPROJ – The Genome Compiler project. Advanced format for genetic data to be designed, shared and visualized.
• GenBank – The flatfile format used by the NCBI to represent database records for nucleotide and peptide sequences from the GenBank and RefSeq databases
• GFF – The General feature format is used to describe genes and other features of DNA, RNA, and protein sequences
• GTF – The Gene transfer format is used to hold information about gene structure
• MAF – The Multiple Alignment Format stores multiple alignments for whole-genome to whole-genome comparisons [1]
• NCBI – Structured ASN.1 format used at National Center for Biotechnology Information for DNA and protein data
• NEXUS – The Nexus file encodes mixed information about genetic sequence data in a block structured format
• NeXML – XML format for phylogenetic trees
• NWK – The Newick tree format is a way of representing graph-theoretical trees with edge lengths using parentheses and commas and useful to hold phylogenetic trees.
• PDB – structures of biomolecules deposited in Protein Data Bank, also used to exchange protein and nucleic acid structures
• PHD – Phred output, from the base-calling software Phred
• PLN – Protein Line Notation used in proteax software specification
• SAM – SAM, Sequence Alignment Map format, in which the results of the 1000 Genomes Project will be released
• SBML – The Systems Biology Markup Language is used to store biochemical network computational models
• SCF – Staden chromatogram files used to store data from DNA sequencing
• SFF – Standard Flowgram Format
• SRA – format used by the National Center for Biotechnology Information Short Read Archive to store high-throughput DNA sequence data
• Stockholm – The Stockholm format for representing multiple sequence alignments
• Swiss-Prot – The flatfile format used to represent database records for protein sequences from the Swiss-Prot database
• VCF – Variant Call Format, a standard created by the 1000 Genomes Project that lists and annotates the entire collection of human variants (with the exception of approximately 1.6 million variants).

Biomedical imaging[edit]

• .dcm – Digital Imaging and Communications in Medicine (DICOM)
• NIfTI – Neuroimaging Informatics Technology Initiative
• .nii – single-file (combined data and meta-data) style
• .nii.gz – gzip-compressed, used transparently by some software, notably the FMRIB Software Library (FSL)
• .gii – single-file (combined data and meta-data) style; NIfTI offspring for brain surface data
• .img, .hdr – dual-file (separate data and meta-data, respectively) style
• .BRIK, .HEAD – AFNI data, meta-data
• .MGH – uncompressed, Massachusetts General Hospital imaging format, used by the FreeSurfer brain analysis package
• .MGZ – zip-compressed, Massachusetts General Hospital imaging format, used by the FreeSurfer brain analysis package
• .img, .hdr – Analyze data, meta-data
• MINC – Medical Imaging NetCDF format
• .mnc – previously based on NetCDF; since version 2.0, based on HDF5

Biomedical signals (time series)[edit]

• ACQ – AcqKnowledge format for Windows/PC from Biopac Systems Inc., Goleta, CA, USA
• ADICHT – LabChart format from ADInstruments Pty Ltd, Bella Vista NSW, Australia
• BCI2000 – The BCI2000 project, Albany, NY, USA
• BDF – BioSemi data format from BioSemi B.V. Amsterdam, Netherlands
• BKR – The EEG data format developed at the University of Technology Graz, Austria
• CFWB – Chart Data Format from ADInstruments Pty Ltd, Bella Vista NSW, Australia
• DICOM – Waveform An extension of Dicom for storing waveform data
• ecgML – A markup language for electrocardiogram data acquisition and analysis
• EDF, EDF+ – European Data Format
• FEF – File Exchange Format for Vital signs, CEN TS 14271
• GDF – The General Data Format for biomedical signals
• HL7aECG – Health Level 7 v3 annotated ECG
• MFER – Medical waveform Format Encoding Rules
• OpenXDF – Open Exchange Data Format from Neurotronics, Inc., Gainesville, FL, USA
• SCP-ECG – Standard Communication Protocol for Computer assisted electrocardiography EN1064:2007
• SIGIF – A digital SIGnal Interchange Format with application in neurophysiology
• WFDB – Format of Physiobank
• XDF – eXtensible Data Format

Other biomedical formats[edit]

• HL7 – Health Level 7, a framework for exchange, integration, sharing, and retrieval of health information electronically
• xDT – a family of data exchange formats for medical records

Biometric formats[edit]

• CBF – Common Biometric Format, based on CBEFF 2.0 (Common Biometric ExFramework).
• EBF – Extended Biometric Format, based on CBF but with S/MIME encryption support and semantic extensions
• CBFX – XML Common Biometric Format, based upon XCBF 1.1 (OASIS XML Common Biometric Format)
• EBFX – XML Extended Biometric Format, based on CBFX but with W3C XML Encryption support and semantic extensions

Programming languages and scripts[edit]

• ADB – Ada body
• ADS – Ada specification
• AHK – AutoHotkey script file
• APPLESCRIPT – applescript: see SCPT
• AS – Adobe Flash ActionScript File
• AU3 – AutoIt version 3
• AWK — AWK
• BAT – Batch file
• BAS – QBasic & QuickBASIC
• BTM — Batch file
• CLASS — Compiled Java binary
• CLJS – ClojureScript
• CMD – Batch file
• Coffee – CoffeeScript
• C – C
• CIA — Nintendo 3DS Software Installation File
• CPP – C++
• CS – C#
• INO – Arduino sketch (program)
• EGG – Chicken
• EGT – EGT Asterisk Application Source File, EGT Universal Document
• ERB – Embedded Ruby, Ruby on Rails Script File
• GO – Go
• HTA – HTML Application
• IBI – Icarus script
• ICI – ICI
• IJS – J script
• .ipynb – IPython Notebook
• ITCL – Itcl
• JS – JavaScript and JScript
• JSFL – Adobe JavaScript language
• .kt – Kotlin
• LUA – Lua
• M – Mathematica package file
• MRC – mIRC Script
• NCF – NetWare Command File^[17][18] (scripting for Novell’s NetWare OS)
• NUC – compiled script
• NUD – C++ External module written in C++
• NUT – Squirrel
• nqp – Raku language Not Quite Perl, or Raku bootstrapping language^[19]
• O — Compiled and optimized C/C++ binary
• pde – Processing (programming language), Processing script
• PHP – PHP
• PHP? – PHP (? = version number)
• PL – Perl
• PM – Perl module
• PS1 – Windows PowerShell shell script
• PS1XML – Windows PowerShell format and type definitions
• PSC1 – Windows PowerShell console file
• PSD1 – Windows PowerShell data file
• PSM1 – Windows PowerShell module file
• PY – Python
• PYC – Python byte code files
• PYO – Python
• R – R scripts
• r – REBOL scripts
• raku – Raku language Raku script (compiled into memory)^[20]
• rakumod – Raku language Raku module (precompiled)
• rakudoc – Raku language Raku documentation file (a slang or sublanguage of Raku)
• rakutest – Raku language Unit test files in Raku
• RB – Ruby
• RDP – RDP connection
• red – Red scripts
• RS – Rust (programming language)
• SB2, SB3 – Scratch
• SCPT – Applescript
• SCPTD – See SCPT.
• SDL – State Description Language
• SH – Shell script
• SYJS – SyMAT JavaScript
• SYPY – SyMAT Python
• TCL – Tcl
• TNS – Ti-Nspire Code/File
• TS – TypeScript
• VBS – Visual Basic Script
• XPL – XProc script/pipeline
• ebuild – Gentoo Linux’s portage package.

Security[edit]

Authentication and general encryption formats are listed here.

• OMF – OpenPGP Message Format used by Pretty Good Privacy, GNU Privacy Guard, and other OpenPGP software; can contain keys, signed data, or encrypted data; can be binary or text («ASCII armored»)

Certificates and keys[edit]

• GXK – Galaxkey, an encryption platform for authorized, private and confidential email communication^{[citation needed]}
• .ssh – OpenSSH private key, Secure Shell private key; format generated by ssh-keygen or converted from PPK with PuTTYgen^[21][22][23]
• .pub – OpenSSH public key, Secure Shell public key; format generated by ssh-keygen or PuTTYgen^[21][22][23]
• .ppk – PuTTY private key, Secure Shell private key, in the format generated by PuTTYgen instead of the format used by OpenSSH^[21][22][23]
• .nSign – nSign public key nSign public key in a custom format^[24]

X.509[edit]

• .cer, .crt, .der – Distinguished Encoding Rules stores certificates
• .p7b, .p7c – PKCS#7 SignedData commonly appears without main data, just certificates or certificate revocation lists (CRLs)
• .p12, .pfx – PKCS#12 can store public certificates and private keys
• PEM – Privacy-enhanced Electronic Mail: full format not widely used, but often used to store Distinguished Encoding Rules in Base64 format
• PFX – Microsoft predecessor of PKCS#12

Encrypted files[edit]

This section shows file formats for encrypted general data, rather than a specific program’s data.

• AXX – Encrypted file, created with AxCrypt
• EEA – An encrypted CAB, ostensibly for protecting email attachments
• TC – Virtual encrypted disk container, created by TrueCrypt
• KODE – Encrypted file, created with KodeFile
• nSignE – An encrypted private key, created by nSign^[24]

Password files[edit]

Password files (sometimes called keychain files) contain lists of other passwords, usually encrypted.

• BPW – Encrypted password file created by Bitser password manager
• KDB – KeePass 1 database
• KDBX – KeePass 2 database

Signal data (non-audio)[edit]

• ACQ – AcqKnowledge format for Windows/PC from Biopac
• ADICHT – LabChart format from ADInstruments
• BKR – The EEG data format developed at the University of Technology Graz
• BDF, CFG – Configuration file for Comtrade data
• CFWB – Chart Data format from ADInstruments
• DAT – Raw data file for Comtrade data
• EDF – European data format
• FEF – File Exchange Format for Vital signs
• GDF – General data formats for biomedical signals
• GMS – Gesture And Motion Signal format
• IROCK – intelliRock Sensor Data File Format
• MFER – Medical waveform Format Encoding Rules
• SAC – Seismic Analysis Code, earthquake seismology data format^[25]
• SCP-ECG – Standard Communication Protocol for Computer assisted electrocardiography
• SEED, MSEED – Standard for the Exchange of Earthquake Data, seismological data and sensor metadata^[26]
• SEGY – Reflection seismology data format
• SIGIF – SIGnal Interchange Format
• WIN, WIN32 – NIED/ERI seismic data format (.cnt)^[27]

Sound and music[edit]

Lossless audio[edit]

Uncompressed[edit]

• 8SVX – Commodore-Amiga 8-bit sound (usually in an IFF container)
• 16SVX – Commodore-Amiga 16-bit sound (usually in an IFF container)
• AIFF, AIF, AIFC – Audio Interchange File Format
• AU – Simple audio file format introduced by Sun Microsystems
• AUP3 — Audacity’s file for when you save a song
• BWF – Broadcast Wave Format, an extension of WAVE
• CDDA – Compact Disc Digital Audio
• DSF, DFF – Direct Stream Digital audio file, also used in Super Audio CD
• RAW – Raw samples without any header or sync
• WAV – Microsoft Wave
• CWAV — file read by the Nintendo 3DS for Home-screen sound effects

Compressed[edit]

• RA, RM – RealAudio format
• FLAC – Free lossless codec of the Ogg project
• LA – Lossless audio
• PAC – LPAC
• APE – Monkey’s Audio
• OFR, OFS, OFF – OptimFROG
• RKA – RKAU
• SHN – Shorten
• TAK – Tom’s Lossless Audio Kompressor^[28]
• THD – Dolby TrueHD
• TTA – Free lossless audio codec (True Audio)
• WV – WavPack
• WMA – Windows Media Audio 9 Lossless
• BCWAV — Nintendo 3DS Home-screen BGM file
• BRSTM – Binary Revolution Stream^[29]
• DTS, DTSHD, DTSMA – DTS (sound system)
• AST – Nintendo Audio Stream
• AW – Nintendo Audio Sample used in first-party games
• PSF – Portable Sound Format, PlayStation variant (originally PlayStation Sound Format)

Lossy audio[edit]

• AC3 – Usually used for Dolby Digital tracks
• AMR – For GSM and UMTS based mobile phones
• MP1 – MPEG Layer 1
• MP2 – MPEG Layer 2
• MP3 – MPEG Layer 3
• SPX – Speex (Ogg project, specialized for voice, low bitrates)
• GSM – GSM Full Rate, originally developed for use in mobile phones
• WMA – Windows Media Audio
• AAC – Advanced Audio Coding (usually in an MPEG-4 container)
• MPC – Musepack
• VQF – Yamaha TwinVQ
• OTS – Audio File (similar to MP3, with more data stored in the file and slightly better compression; designed for use with OtsLabs’ OtsAV)
• SWA – Adobe Shockwave Audio (Same compression as MP3 with additional header information specific to Adobe Director)
• VOX – Dialogic ADPCM Low Sample Rate Digitized Voice
• VOC – Creative Labs Soundblaster Creative Voice 8-bit & 16-bit Also output format of RCA Audio Recorders
• DWD – DiamondWare Digitized
• SMP – Turtlebeach SampleVision
• OGG – Ogg Vorbis

Tracker modules and related[edit]

• MOD – Soundtracker and Protracker sample and melody modules
• MT2 – MadTracker 2 module
• S3M – Scream Tracker 3 module
• XM – Fast Tracker module
• IT – Impulse Tracker module
• NSF – NES Sound Format
• MID, MIDI – Standard MIDI file; most often just notes and controls but occasionally also sample dumps (.mid, .rmi)
• FTM – FamiTracker Project file
• BTM – BambooTracker Project file

Sheet music files[edit]

• ABC – ABC Notation sheet music file
• DARMS – DARMS File Format also known as the Ford-Columbia Format
• ETF – Enigma Transportation Format abandoned sheet music exchange format
• GP – Guitar Pro sheet music and tablature file
• KERN – Kern File Format sheet music file
• LY – LilyPond sheet music file
• MEI – Music Encoding Initiative file format that attempts to encode all musical notations
• MIDI — MIDI file format that is a music sheet for instruments
• MUS, MUSX – Finale sheet music file
• MXL, XML – MusicXML standard sheet music exchange format
• MSCX, MSCZ – MuseScore sheet music file
• SMDL – Standard Music Description Language sheet music file
• SIB – Sibelius sheet music file

Other file formats pertaining to audio[edit]

• NIFF – Notation Interchange File Format
• PTB – Power Tab Editor tab
• ASF – Advanced Systems Format
• CUST – DeliPlayer custom sound format
• GYM – Genesis YM2612 log
• JAM – Jam music format
• MNG – Background music for the Creatures game series, starting from Creatures 2
• RMJ – RealJukebox Media used for RealPlayer
• SID – Sound Interface Device – Commodore 64 instructions to play SID music and sound effects
• SPC – Super NES sound format
• TXM – Track ax media
• VGM – Stands for «Video Game Music», log for several different chips
• YM – Atari ST/Amstrad CPC YM2149 sound chip format
• PVD – Portable Voice Document used for Oaisys & Mitel call recordings

Playlist formats[edit]

• AIMPPL – AIMP Playlist format
• ASX – Advanced Stream Redirector
• RAM – Real Audio Metafile For RealAudio files only.
• XPL – HDi playlist
• XSPF – XML Shareable Playlist Format
• ZPL – Xbox Music (Formerly Zune) Playlist format from Microsoft
• M3U – Multimedia playlist file
• PLS – Multimedia playlist, originally developed for use with the museArc

Audio editing and music production[edit]

• ALS – Ableton Live set
• ALC – Ableton Live clip
• ALP – Ableton Live pack
• ATMOS, AUDIO, METADATA – Dolby Atmos Rendering and Mastering related file
• AUP – Audacity project file
• AUP3 – Audacity 3.0 project file
• BAND – GarageBand project file
• CEL – Adobe Audition loop file (Cool Edit Loop)
• CAU – Caustic project file
• CPR – Steinberg Cubase project file
• CWP – Cakewalk Sonar project file
• DRM – Steinberg Cubase drum file
• DMKIT – Image-Line’s Drumaxx drum kit file
• ENS – Native Instruments Reaktor Ensemble
• FLM – Image Line FL Studio Mobile project file
• FLP – Image Line FL Studio project file
• GRIR – Native Instruments Komplete Guitar Rig Impulse Response
• LOGIC – Logic Pro X project file
• MMP – LMMS project file (alternatively MMPZ for compressed formats)
• MMR – MAGIX Music Maker project file
• MX6HS – Mixcraft 6 Home Studio project file
• NPR – Steinberg Nuendo project file
• OMF, OMFI – Open Media Framework Interchange OMFI succeeds OMF (Open Media Framework)
• PTX – Pro Tools 10 or later project file
• PTF – Pro Tools 7 up to Pro Tools 9 project file
• PTS – Legacy Pro Tools project file
• RIN – Soundways RIN-M file containing sound recording participant credits and song information
• RPP, RPP-BAK – REAPER project file
• REAPEAKS – REAPER peak (waveform cache) file
• SES – Adobe Audition multitrack session file
• SFK – Sound Forge waveform cache file
• SFL – Sound Forge sound file
• SNG – MIDI sequence file (MidiSoft, Korg, etc.) or n-Track Studio project file
• STF – StudioFactory project file. It contains all necessary patches, samples, tracks and settings to play the file
• SND – Akai MPC sound file
• SYN – SynFactory project file. It contains all necessary patches, samples, tracks and settings to play the file
• UST – Utau Editor sequence excluding wave-file
• VCLS – VocaListener project file
• VPR – Vocaloid 5 Editor sequence excluding wave-file
• VSQ – Vocaloid 2 Editor sequence excluding wave-file
• VSQX – Vocaloid 3 & 4 Editor sequence excluding wave-file
• 🗿 – ThirtyDollar Project file

Recorded television formats[edit]

• DVR-MS – Windows XP Media Center Edition’s Windows Media Center recorded television format
• WTV – Windows Vista’s and up Windows Media Center recorded television format

Source code for computer programs[edit]

• ADA, ADB, 2.ADA – Ada (body) source
• ADS, 1.ADA – Ada (specification) source
• ASM, S – Assembly language source
• BAS – BASIC, FreeBASIC, Visual Basic, BASIC-PLUS source,^[14] PICAXE basic
• BB – Blitz Basic Blitz3D
• BMX – Blitz Basic BlitzMax
• C – C source
• CLJ – Clojure source code
• CLS – Visual Basic class
• COB, CBL – COBOL source
• CPP, CC, CXX, C, CBP – C++ source
• CS – C# source
• CSPROJ – C# project (Visual Studio .NET)
• D – D source
• DBA – DarkBASIC source
• DBPro123 – DarkBASIC Professional project
• E – Eiffel source
• EFS – EGT Forever Source File
• EGT – EGT Asterisk Source File, could be J, C#, VB.net, EF 2.0 (EGT Forever)
• EL – Emacs Lisp source
• FOR, FTN, F, F77, F90 – Fortran source
• FRM – Visual Basic form
• FRX – Visual Basic form stash file (binary form file)
• FTH – Forth source
• GED – Game Maker Extension Editable file as of version 7.0
• GM6 – Game Maker Editable file as of version 6.x
• GMD – Game Maker Editable file up to version 5.x
• GMK – Game Maker Editable file as of version 7.0
• GML – Game Maker Language script file
• GO – Go source
• H – C/C++ header file
• HPP, HXX – C++ header file
• HS – Haskell source
• I – SWIG interface file
• INC – Turbo Pascal included source
• JAVA – Java source
• L – lex source
• LGT – Logtalk source
• LISP – Common Lisp source
• M – Objective-C source
• M – MATLAB
• M – Mathematica
• M4 – m4 source
• ML – Standard ML and OCaml source
• MSQR – M² source file, created by Mattia Marziali
• N – Nemerle source
• NB – Nuclear Basic source
• P – Parser source
• PAS, PP, P – Pascal source (DPR for projects)
• PHP, PHP3, PHP4, PHP5, PHPS, Phtml – PHP source
• PIV – Pivot stickfigure animator
• PL, PM – Perl
• PLI, PL1 – PL/I
• PRG – Ashton-Tate; dbII, dbIII and dbIV, db, db7, clipper, Microsoft Fox and FoxPro, harbour, xharbour, and Xbase
• PRO – IDL
• POL – Apcera Policy Language doclet
• PY – Python source
• R – R source
• raku, rakumod, rakudoc, rakutest, nqp – Raku Language
• RED – Red source
• REDS – Red/System source
• RB – Ruby source
• RESX – Resource file for .NET applications
• RC, RC2 – Resource script files to generate resources for .NET applications
• RKT, RKTL – Racket source
• SCALA – Scala source
• SCI, SCE – Scilab
• SCM – Scheme source
• SD7 – Seed7 source
• SKB, SKC – Sage Retrieve 4GL Common Area (Main and Amended backup)
• SKD – Sage Retrieve 4GL Database
• SKF, SKG – Sage Retrieve 4GL File Layouts (Main and Amended backup)
• SKI – Sage Retrieve 4GL Instructions
• SKK – Sage Retrieve 4GL Report Generator
• SKM – Sage Retrieve 4GL Menu
• SKO – Sage Retrieve 4GL Program
• SKP, SKQ – Sage Retrieve 4GL Print Layouts (Main and Amended backup)
• SKS, SKT – Sage Retrieve 4GL Screen Layouts (Main and Amended backup)
• SKZ – Sage Retrieve 4GL Security File
• SLN – Visual Studio solution
• SPIN – Spin source (for Parallax Propeller microcontrollers)
• STK – Stickfigure file for Pivot stickfigure animator
• SWG – SWIG source code
• TCL – Tcl source code
• VAP – Visual Studio Analyzer project
• VB – Visual Basic.NET source
• VBG – Visual Studio compatible project group
• VBP, VIP – Visual Basic project
• VBPROJ – Visual Basic .NET project
• VCPROJ – Visual C++ project
• VDPROJ – Visual Studio deployment project
• XPL – XProc script/pipeline
• XQ – XQuery file
• XSL – XSLT stylesheet
• Y – yacc source

Spreadsheet[edit]

• 123 – Lotus 1-2-3
• AB2 – Abykus worksheet
• AB3 – Abykus workbook
• AWS – Ability Spreadsheet
• BCSV – Nintendo proprietary table format
• CLF – ThinkFree Calc
• CELL – Haansoft(Hancom) SpreadSheet software document
• CSV – Comma-Separated Values
• GSHEET – Google Drive Spreadsheet
• numbers – An Apple Numbers Spreadsheet file
• gnumeric – Gnumeric spreadsheet, a gziped XML file
• LCW – Lucid 3-D
• ODS – OpenDocument spreadsheet
• OTS – OpenDocument spreadsheet template
• QPW – Quattro Pro spreadsheet
• SDC – StarOffice StarCalc Spreadsheet
• SLK – SYLK (SYmbolic LinK)
• STC – OpenOffice.org XML (obsolete) Spreadsheet template
• SXC – OpenOffice.org XML (obsolete) Spreadsheet
• TAB – tab delimited columns; also TSV (Tab-Separated Values)
• TXT – text file
• VC – Visicalc
• WK1 – Lotus 1-2-3 up to version 2.01
• WK3 – Lotus 1-2-3 version 3.0
• WK4 – Lotus 1-2-3 version 4.0
• WKS – Lotus 1-2-3
• WKS – Microsoft Works
• WQ1 – Quattro Pro DOS version
• XLK – Microsoft Excel worksheet backup
• XLS – Microsoft Excel worksheet sheet (97–2003)
• XLSB – Microsoft Excel binary workbook
• XLSM – Microsoft Excel Macro-enabled workbook
• XLSX – Office Open XML worksheet sheet
• XLR – Microsoft Works version 6.0
• XLT – Microsoft Excel worksheet template
• XLTM – Microsoft Excel Macro-enabled worksheet template
• XLW – Microsoft Excel worksheet workspace (version 4.0)

Tabulated data[edit]

• TSV – Tab-separated values
• CSV – Comma-separated values
• db – databank format; accessible by many econometric applications
• dif – accessible by many spreadsheet applications

Video[edit]

• AAF – mostly intended to hold edit decisions and rendering information, but can also contain compressed media essence
• 3GP – the most common video format for cell phones
• GIF – Animated GIF (simple animation; until recently often avoided because of patent problems)
• ASF – container (enables any form of compression to be used; MPEG-4 is common; video in ASF-containers is also called Windows Media Video (WMV))
• AVCHD – Advanced Video Codec High Definition
• AVI – container (a shell, which enables any form of compression to be used)
• .bik – BIK Bink Video file. A video compression system developed by RAD Game Tools
• BRAW – a video format used by Blackmagic’s Ursa Mini Pro 12K cameras.
• CAM – aMSN webcam log file
• COLLAB – Blackboard Collaborate session recording
• DAT – video standard data file (automatically created when we attempted to burn as video file on the CD)
• DVR-MS – Windows XP Media Center Edition’s Windows Media Center recorded television format
• FLV – Flash video (encoded to run in a flash animation)
• MPEG-1 – M1V Video
• MPEG-2 – M2V Video
• NOA – rare movie format use in some Japanese eroges around 2002
• FLA – Adobe Flash (for producing)
• FLR – (text file which contains scripts extracted from SWF by a free ActionScript decompiler named FLARE)
• SOL – Adobe Flash shared object («Flash cookie»)
• STR – Sony PlayStation video stream
• M4V – video container file format developed by Apple
• .mkv – Matroska Matroska is a container format, which enables any video format such as MPEG-4 ASP or AVC to be used along with other content such as subtitles and detailed meta information
• WRAP – MediaForge (*.wrap)
• MNG – mainly simple animation containing PNG and JPEG objects, often somewhat more complex than animated GIF
• .mov – QuickTime container which enables any form of compression to be used; Sorenson codec is the most common; QTCH is the filetype for cached video and audio streams
• .mpeg, .mpg, .mpe — MPEG
• THP – Nintendo proprietary movie/video format
• MPEG-4 – MPEG-4 Part 14, shortened «MP4» multimedia container (most often used for Sony’s PlayStation Portable and Apple’s iPod)
• MXF – Material Exchange Format (standardized wrapper format for audio/visual material developed by SMPTE)
• ROQ – used by Quake III Arena
• NSV – NSV Nullsoft Streaming Video (media container designed for streaming video content over the Internet)
• Ogg – container, multimedia
• RM – RealMedia
• SVI – SVI Samsung video format for portable players
• SMI – SMI SAMI Caption file (HTML like subtitle for movie files)
• .smk – SMK Smacker video file. A video compression system developed by RAD Game Tools
• SWF – Adobe Flash (for viewing)
• WMV – Windows Media Video (See ASF)
• WTV – Windows Vista’s and up Windows Media Center recorded television format
• YUV – raw video format; resolution (horizontal x vertical) and sample structure 4:2:2 or 4:2:0 must be known explicitly
• WebM – video file format for web video using HTML5

Video editing, production[edit]

• BRAW – Blackmagic Design RAW video file name
• DRP – Davinci Resolve 17 project file
• FCP – Final Cut Pro project file
• MSWMM – Windows Movie Maker project file
• PPJ, PRPROJ – Adobe Premiere Pro video editing file
• IMOVIEPROJ – iMovie project file
• VEG, VEG-BAK – Sony Vegas project file
• SUF – Sony camera configuration file (setup.suf) produced by XDCAM-EX camcorders
• WLMP – Windows Live Movie Maker project file
• KDENLIVE – Kdenlive project file
• VPJ – VideoPad project file
• MOTN – Apple Motion project file
• IMOVIEMOBILE – iMovie project file for iOS users
• WFP, WVE — Wondershare Filmora Project
• PDS – Cyberlink PowerDirector project
• VPROJ – VSDC Free Video Editor project file

Video game data[edit]

List of common file formats of data for video games on systems that support filesystems, most commonly PC games.
Minecraft — files used by Mojang to develop Minecraft

• MCADDON – format used by the Bedrock Edition of Minecraft for add-ons; Resource packs for the game
• MCFUNCTION – format used by Minecraft for storing functions
• MCMETA – format used by Minecraft for storing data for customizable texture packs for the game
• MCPACK – format used by the Bedrock Edition of Minecraft for in-game texture packs; full addons for the game
• MCR – format used by Minecraft for storing data for in-game worlds before version 1.2
• MCTEMPLATE – format used by the Bedrock Edition of Minecraft for world templates
• MCWORLD – format used by the Bedrock Edition of Minecraft for in-game worlds
• NBS – format used by Note Block Studio, a tool that can be used to make note block songs for Minecraft.

TrackMania/Maniaplanet Engine – Formats used by games based on the TrackMania engine.

• GBX – All user-created content is stored in this file type.
  • REPLAY.GBX – Stores the replay of a race.
  • CHALLENGE.GBX, MAP.GBX – Stores tracks/maps.
  • SYSTEMCONFIG.GBX – Launcher info.
  • TRACKMANIAVEHICLE.GBX – Info about a certain car type.
  • VEHICLETUNINGS.GBX – Vehicle physics.
  • SOLID.GBX – A block’s model.
  • ITEM.GBX – Custom Maniaplanet item.
  • BLOCK.GBX – Custom Maniaplanet block.
  • TEXTURE.GBX – Info about a texture that are used in materials.
  • MATERIAL.GBX – Info about a material such as surface type that are used in Solids.
  • TMEDCLASSIC.GBX – Block info.
  • GHOST.GBX – Player ghosts in Trackmania and TrackMania Turbo.
  • CONTROLSTYLE.GBX – Menu files.
  • SCORES.GBX – Stores info about the player’s best times.
  • PROFILE.GBX – Stores a player’s info such as their login.
• DDS – Almost every texture in the game uses this format.
• PAK – Stores environment data such as valid blocks.
• LOC – A locator. Locators allow the game to download content such as car skins from an external server.
• SCRIPT.TXT – Scripts for Maniaplanet such as menus and game modes.
• XML – ManiaLinks.

Doom engine – Formats used by games based on the Doom engine.

• DEH – DeHackEd files to mutate the game executable (not officially part of the DOOM engine)
• DSG – Saved game
• LMP – A lump is an entry in a DOOM wad.
• LMP – Saved demo recording
• MUS – Music file (usually contained within a WAD file)
• WAD – Data storage (contains music, maps, and textures)

Quake engine – Formats used by games based on the Quake engine.

• BSP – BSP: (For Binary space partitioning) compiled map format
• MAP – MAP: Raw map format used by editors like GtkRadiant or QuArK
• MDL, MD2, MD3, MD5 – MDL/MD2/MD3/MD5: Model for an item used in the game
• PAK, PK2 – PAK/PK2: Data storage
• PK3, PK4 – PK3/PK4: used by the Quake II, Quake III Arena and Quake 4 game engines, respectively, to store game data, textures etc. They are actually .zip files.
• .dat – not specific file type, often generic extension for «data» files for a variety of applications
  • sometimes used for general data contained within the .PK3/PK4 files
  • .fontdat – a .dat file used for formatting game fonts
• .roq – Video format
• .sav – Savegame format

Unreal Engine – Formats used by games based on the Unreal engine.

• U – Unreal script format
• UAX – Animations format for Unreal Engine 2
• UMX – Map format for Unreal Tournament
• UMX – Music format for Unreal Engine 1
• UNR – Map format for Unreal
• UPK – Package format for cooked content in Unreal Engine 3
• USX – Sound format for Unreal Engine 1 and Unreal Engine 2
• UT2 – Map format for Unreal Tournament 2003 and Unreal Tournament 2004
• UT3 – Map format for Unreal Tournament 3
• UTX – Texture format for Unreal Engine 1 and Unreal Engine 2
• UXX – Cache format; these are files a client downloaded from server (which can be converted to regular formats)

Duke Nukem 3D Engine – Formats used by games based on this engine

• DMO – Save game
• GRP – Data storage
• MAP – Map (usually constructed with BUILD.EXE)

Diablo Engine – Formats used by Diablo by Blizzard Entertainment.

• SV – Save Game
• ITM – Item File

Real Virtuality Engine – Formats used by Bohemia Interactive. Operation:Flashpoint, ARMA 2, VBS2

• SQF – Format used for general editing
• SQM – Format used for mission files
• PBO – Binarized file used for compiled models
• LIP – Format that is created from WAV files to create in-game accurate lip-synch for character animations.

Source Engine – Formats used by Valve. Half-Life 2, Counter-Strike: Source, Day of Defeat: Source, Half-Life 2: Episode One, Team Fortress 2, Half-Life 2: Episode Two, Portal, Left 4 Dead, Left 4 Dead 2, Alien Swarm, Portal 2, Counter-Strike: Global Offensive, Titanfall, Insurgency, Titanfall 2, Day of Infamy

• VMF – Valve Hammer Map editor raw map file
• VMX – Valve Hammer Map editor backup map file
• BSP – Source Engine compiled map file
• MDL – Source Engine model format
• SMD – Source Engine uncompiled model format
• PCF – Source Engine particle effect file
• HL2 – Half-Life 2 save format
• DEM – Source Engine demo format
• VPK – Source Engine pack format
• VTF – Source Engine texture format
• VMT – Source Engine material format.

Pokemon Generation V

• CGB – Pokemon Black and White/Pokemon Black 2 and White 2 C-Gear skins.

Other Formats

• ARC – used to store New Super Mario Bros. Wii level data
• B – used for Grand Theft Auto saved game files
• BOL – used for levels on Poing!PC
• DBPF – The Sims 2, DBPF, Package
• DIVA – Project DIVA timings, element coördinates, MP3 references, notes, animation poses and scores.
• ESM, ESP – Master and Plugin data archives for the Creation Engine
• HAMBU – format used by the Aidan’s Funhouse game RGTW for storing map data^[30]
• HE0, HE2, HE4 – HE games File
• GCF – format used by the Steam content management system for file archives
• IMG – format used by Renderware-based Grand Theft Auto games for data storage
• LOVE – format used by the LOVE2D Engine^[31]
• MAP – format used by Halo: Combat Evolved for archive compression, Doom³, and various other games
• MCA – format used by Minecraft for storing data for in-game worlds^[32]
• NBT – format used by Minecraft for storing program variables along with their (Java) type identifiers
• OEC – format used by OE-Cake for scene data storage
• OSB – osu! storyboard data
• OSC – osu!stream combined stream data
• OSF2 – free osu!stream song file
• OSR – osu! replay data
• OSU – osu! beatmap data
• OSZ2 – paid osu!stream song file
• P3D – format for panda3d by Disney
• PLAGUEINC – format used by Plague Inc. for storing custom scenario information^[33]
• POD – format used by Terminal Reality
• RCT – Used for templates and save files in RollerCoaster Tycoon games
• REP – used by Blizzard Entertainment for scenario replays in StarCraft.
• Simcity, DBPF, .dat, .SC4Lot, .SC4Model – All game plugins use this format, commonly with different file extensions(Simcity 4)
• SMZIP – ZIP-based package for StepMania songs, themes and announcer packs.
• SOLITAIRETHEME8 – A solitaire theme for Windows solitaire
• USLD – format used by Unison Shift to store level layouts.
• VVVVVV – format used by VVVVVV
• CPS – format used by The Powder Toy, Powder Toy save
• STM – format used by The Powder Toy, Powder Toy stamp
• PKG – format used by Bungie for the PC Beta of Destiny 2, for nearly all the game’s assets.
• CHR – format used by Team Salvato, for the character files of Doki Doki Literature Club!
• Z5 – format used by Z-machine for story files in interactive fiction.
• scworld – format used by Survivalcraft to store sandbox worlds.
• scskin – format used by Survivalcraft to store player skins.
• scbtex – format used by Survivalcraft to store block textures.
• prison – format used by Prison Architect to save prisons
• escape – format used by Prison Architect to save escape attempts
• WBFS — (Wii Backup File System)
• .GBA — Game Boy Advance ROM File
• .pss — Sony PlayStation 2 Game Video file and is used to store audio and video data by games for the Playstation 2 console.

Video game storage media[edit]

List of the most common filename extensions used when a game’s ROM image or storage medium is copied from an original read-only memory (ROM) device to an external memory such as hard disk for back up purposes or for making the game playable with an emulator. In the case of cartridge-based software, if the platform specific extension is not used then filename extensions «.rom» or «.bin» are usually used to clarify that the file contains a copy of a content of a ROM. ROM, disk or tape images usually do not consist of one file or ROM, rather an entire file or ROM structure contained within one file on the backup medium.^[34]

• .a26 – Atari 2600
• .a52 – Atari 5200
• .a78 – Atari 7800
• .lnx – Atari Lynx
• .jag, .j64 – Atari Jaguar
• .iso, .wbfs, .wad, .wdf – Wii and WiiU
• .gcm, .iso – GameCube
• .min – Pokemon mini
• .nds – Nintendo DS
• .dsi – Nintendo DSiWare
• .3ds – Nintendo 3DS
• .cia – Nintendo 3DS Installation File (for installing games with the use of the FBI homebrew application)
• .gb – Game Boy (this applies to the original Game Boy and the Game Boy Color)
• .gbc – Game Boy Color
• .gba – Game Boy Advance
• .sav – Game Boy Advance Saved Data Files
• .sgm – Visual Boy Advance Save States
• .n64, .v64, .z64, .u64, .usa, .jap, .pal, .eur, .bin – Nintendo 64
• .pj – Project 64 Save States
• .nes – Nintendo Entertainment System^[35]
• .fds – Famicom Disk System
• .jst – Jnes Save States
• .fc# – FCEUX Save States (.fc#, where # is any character, usually a number)
• .gg – Game Gear
• .sms – Master System
• .sg – SG-1000
• .smd, .bin – Mega Drive/Genesis
• .32x – Sega 32X
• .smc, .078, .sfc – Super NES (.078 is for split ROMs, which are rare)
• .fig – Super Famicom (Japanese releases are rarely .fig, above extensions are more common)
• .srm – Super NES Saved Data Files
• .zst, .zs1-.zs9, .z10-.z99 – ZSNES Save States (.zst, .zs1-.zs9, .z10-.z99)
• .frz, .000-.008 – Snes9X Save States
• .pce – TurboGrafx-16/PC Engine
• .npc, .ngp – Neo Geo Pocket
• .ngc – Neo Geo Pocket Color
• .vb – Virtual Boy
• .int – Intellivision
• .min – Pokémon Mini
• .vec – Vectrex
• .bin – Odyssey²
• .ws – WonderSwan
• .wsc – WonderSwan Color
• .tzx – ZX Spectrum (for exact copies of ZX Spectrum games)
• TAP – for tape images without copy protection
• Z80, SNA – (for snapshots of the emulator RAM)
• DSK – (for disk images)
• .tap – Commodore 64 (.tap) (for tape images including copy protection)
• T64 – (for tape images without copy protection, considerably smaller than .tap files)
• D64 – (for disk images)
• CRT – (for cartridge images)
• .adf – Amiga (.adf) (for 880K diskette images)
• ADZ – GZip-compressed version of the above.
• DMS – Disk Masher System, previously used as a disk-archiving system native to the Amiga, also supported by emulators.
• .pss — A Sony PlayStation 2 Game Video file and is used to store audio and video data by games for the Playstation 2 console.

Virtual machines[edit]

Microsoft Virtual PC, Virtual Server[edit]

• .vfd – Virtual Floppy Disk
• .vhd – Virtual Hard Disk
• .vud – Virtual Undo Disk
• .vmc – Virtual Machine Configuration
• .vsv – Virtual Machine Saved State

VMware ESX, GSX, Workstation, Player[edit]

• .log – Virtual Machine Logfile
• .vmdk, .dsk – Virtual Machine Disk
• .nvram – Virtual Machine BIOS
• .vmem – Virtual Machine paging file
• .vmsd – Virtual Machine snapshot metadata
• .vmsn – Virtual Machine snapshot
• .vmss, .std – Virtual Machine suspended state
• .vmtm – Virtual Machine team data
• .vmx, .cfg – Virtual Machine configuration
• .vmxf – Virtual Machine team configuration

VirtualBox[edit]

• .vdi – VirtualBox virtual disk image
• .vbox-extpack – VirtualBox extension pack

Parallels Workstation[edit]

• .hdd – Virtual Machine hard disk
• .pvs – Virtual Machine preferences/configuration
• .sav – Virtual Machine saved state

QEMU[edit]

• .cow – Copy-on-write
• .qcow – QEMU copy-on-write
• .qcow2 – QEMU copy-on-write – version 2
• .qed – QEMU enhanced disk format

Web page[edit]

Static

• DTD – Document Type Definition (standard), MUST be public and free
• .html, .htm – HTML HyperText Markup Language
• .xhtml, .xht – XHTML eXtensible HyperText Markup Language
• .mht, .mhtml – MHTML Archived HTML, store all data on one web page (text, images, etc.) in one big file
• .maff – MAF web archive based on ZIP

Dynamically generated

• .asp – ASP Microsoft Active Server Page
• .aspx – ASPX Microsoft Active Server Page. NET
• .adp – ADP AOLserver Dynamic Page
• .bml – BML Better Markup Language (templating)
• .cfm – CFM ColdFusion
• .cgi – CGI
• .ihtml – iHTML Inline HTML
• .jsp – JSP JavaServer Pages
• .las, .lasso, .lassoapp – Lasso, A file created or served with the Lasso Programming Language
• .pl – Perl
• .php, .php?, .phtml – PHP ? is version number (previously abbreviated Personal Home Page, later changed to PHP: Hypertext Preprocessor)
• .shtml – SSI HTML with Server Side Includes (Apache)
• .stm – SSI HTML with Server Side Includes (Apache)

Markup languages and other web standards-based formats[edit]

• .atom, .xml – Atom Another syndication format.
• .eml – EML Format used by several desktop email clients.
• .jsonld – JSON-LD A JSON-based serialization for linked data.
• .kprx – KPRX A XML-based serialization for workflow definition generated by K2.
• .ps – PS A XML-based serialization for test automation scripts called PowerScripts for K2 based applications.
• .metalink, .met – Metalink A format to list metadata about downloads, such as mirrors, checksums, and other information.
• .rss, .xml – RSS Syndication format.
• .markdown, .md – Markdown Plain text formatting syntax, which is popularly used to format «readme» files.
• .se – Shuttle Another lightweight markup language.

Other[edit]

• AXD – cookie extensions found in temporary internet folder
• APK — Android Package Kit
• BDF – Binary Data Format – raw data from recovered blocks of unallocated space on a hard drive
• CBP – CD Box Labeler Pro, CentraBuilder, Code::Blocks Project File, Conlab Project
• CEX – SolidWorks Enterprise PDM Vault File
• COL – Nintendo GameCube proprietary collision file (.col)
• CREDX – CredX Dat File
• DDB – Generating code for Vocaloid singers voice (see .DDI)
• DDI – Vocaloid phoneme library (Japanese, English, Korean, Spanish, Chinese, Catalan)
• DUPX – DuupeCheck database management tool project file
• FTM – Family Tree Maker data file
• FTMB – Family Tree Maker backup file
• GA3 – Graphical Analysis 3
• .ged – GEDCOM (GEnealogical Data COMmunication) format to exchange genealogy data between different genealogy software
• HLP – Windows help file
• IGC – flight tracks downloaded from GPS devices in the FAI’s prescribed format
• INF – similar format to INI file; used to install device drivers under Windows, inter alia.
• JAM – JAM Message Base Format for BBSes
• KMC – tests made with KatzReview’s MegaCrammer
• KCL – Nintendo GameCube/Wii proprietary collision file (.kcl)
• KTR – Hitachi Vantara Pentaho Data Integration/Kettle Transformation Project file
• LNK – Microsoft Windows format for Hyperlinks to Executables
• LSM – LSMaker script file (program using layered .jpg to create special effects; specifically designed to render lightsabers from the Star Wars universe) (.lsm)
• NARC – Archive format used in Nintendo DS games.
• OER – AU OER Tool, Open Educational Resource editor
• PA – Used to assign sound effects to materials in KCL files (.pa)
• PIF – Used to run MS-DOS programs under Windows
• POR – So called «portable» SPSS files, readable by PSPP
• PXZ – Compressed file to exchange media elements with PSALMO
• RISE – File containing RISE generated information model evolution
• SCR – Windows Screen Saver file
• TOPC – TopicCrunch SEO Project file holding keywords, domain, and search engine settings (ASCII)
• XLF – Utah State University Extensible LADAR Format
• XMC – Assisted contact lists format, based on XML and used in kindergartens and schools
• ZED – My Heritage Family Tree
• zone – Zone file a text file containing a DNS zone
• FX – Microsoft DirectX plain text effects and properties for the associated file and are used to specify the textures, shading, rendering, lighting and other 3D effects (.fx)
• MIFRAMES – Mine-imator keyframes file (.miframes)
• MILANGUAGE – Mine-Imator language data file (.milanguage)
• MIDATA – Mine-Imator data file (.midata)
• BCA – Short for Burst Cutting Area Holds the information of the circular area near the center of a DVD, HD DVD or Blu-ray Disc, it is usually 64 bytes in size. (.bca)

Cursors[edit]

• ANI – Animated cursor
• CUR – Cursor file
• Smes – Hawk’s Dock configuration file

Generalized files[edit]

General data formats[edit]

These file formats are fairly well defined by long-term use or a general standard, but the content of each file is often highly specific to particular software or has been extended by further standards for specific uses.

Text-based[edit]

• CSV – comma-separated values
• HTML – hyper text markup language
• CSS – cascading style sheets
• INI – a configuration text file whose format is substantially similar between applications
• JSON – JavaScript Object Notation is an openly used data format now used by many languages, not just JavaScript
• TSV – tab-separated values
• XML – an open data format
• YAML – an open data format
• ReStructuredText – an open text format for technical documents used mainly in the Python programming language
• .md – Markdown an open lightweight markup language to create simple but rich text, often used to format README files
• AsciiDoc – an open human-readable markup document format semantically equivalent to DocBook
• .yni — a configuration file similar to YAML

Generic file extensions[edit]

These are filename extensions and broad types reused frequently with differing formats or no specific format by different programs.

Binary files[edit]

• .bak, .bk – Bak file various backup formats: some just copies of data files, some in application-specific data backup formats, some formats for general file backup programs
• BIN – binary data, often memory dumps of executable code or data to be re-used by the same software that originated it
• DAT – data file, usually binary data proprietary to the program that created it, or an MPEG-1 stream of Video CD
• DSK – file representations of various disk storage images
• RAW – raw (unprocessed) data
• SZH — files that are associated with zero unique file types (the most prevalent being the Binary Data format)

Text files[edit]

• .cnf, .conf, .cfg – configuration file substantially software-specific
• .log – logfiles usually text, but sometimes binary
• .asc, .txt – human-readable plain text, usually no more specific

Partial files[edit]

Differences and patches[edit]

• diff – text file differences created by the program diff and applied as updates by patch

Incomplete transfers[edit]

• .!ut – !UT partly complete uTorrent download
• .crdownload – CRDOWNLOAD partly complete Google Chrome download
• .opdownload – OPDOWNLOAD partly complete Opera download
• .part – PART partly complete Mozilla Firefox or Transmission download
• .partial – PARTIAL partly complete Internet Explorer or Microsoft Edge download

Temporary files[edit]

• .temp, .tmp – Temporary file sometimes in a specific format, but often just raw data in the middle of processing
• Pseudo-pipelines, Pseudo-pipeline – Pseudo-pipeline file used to simulate a software pipe

See also[edit]

• List of filename extensions
• MIME#Content-Type, a standard for referring to file formats
• List of motion and gesture file formats
• List of file signatures, or «magic numbers»

References[edit]

External links[edit]

• File formats at Curlie
• File formats at FileInfo.com

A file format is a standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary or free.

Some file formats are designed for very particular types of data: PNG files, for example, store bitmapped images using lossless data compression. Other file formats, however, are designed for storage of several different types of data: the Ogg format can act as a container for different types of multimedia including any combination of audio and video, with or without text (such as subtitles), and metadata. A text file can contain any stream of characters, including possible control characters, and is encoded in one of various character encoding schemes. Some file formats, such as HTML, scalable vector graphics, and the source code of computer software are text files with defined syntaxes that allow them to be used for specific purposes.

Specifications[edit]

File formats often have a published specification describing the encoding method and enabling testing of program intended functionality. Not all formats have freely available specification documents, partly because some developers view their specification documents as trade secrets, and partly because other developers never author a formal specification document, letting precedent set by other already existing programs that use the format define the format via how these existing programs use it.

If the developer of a format doesn’t publish free specifications, another developer looking to utilize that kind of file must either reverse engineer the file to find out how to read it or acquire the specification document from the format’s developers for a fee and by signing a non-disclosure agreement. The latter approach is possible only when a formal specification document exists. Both strategies require significant time, money, or both; therefore, file formats with publicly available specifications tend to be supported by more programs.

Patents[edit]

Patent law, rather than copyright, is more often used to protect a file format. Although patents for file formats are not directly permitted under US law, some formats encode data using patented algorithms. For example, using compression with the GIF file format requires the use of a patented algorithm, and though the patent owner did not initially enforce their patent, they later began collecting royalty fees. This has resulted in a significant decrease in the use of GIFs, and is partly responsible for the development of the alternative PNG format. However, the GIF patent expired in the US in mid-2003, and worldwide in mid-2004.

Identifying file type[edit]

Different operating systems have traditionally taken different approaches to determining a particular file’s format, with each approach having its own advantages and disadvantages. Most modern operating systems and individual applications need to use all of the following approaches to read «foreign» file formats, if not work with them completely.

Filename extension[edit]

One popular method used by many operating systems, including Windows, macOS, CP/M, DOS, VMS, and VM/CMS, is to determine the format of a file based on the end of its name, more specifically the letters following the final period. This portion of the filename is known as the filename extension. For example, HTML documents are identified by names that end with .html (or .htm), and GIF images by .gif. In the original FAT file system, file names were limited to an eight-character identifier and a three-character extension, known as an 8.3 filename. There are a limited number of three-letter extensions, which can cause a given extension to be used by more than one program. Many formats still use three-character extensions even though modern operating systems and application programs no longer have this limitation. Since there is no standard list of extensions, more than one format can use the same extension, which can confuse both the operating system and users.

One artifact of this approach is that the system can easily be tricked into treating a file as a different format simply by renaming it — an HTML file can, for instance, be easily treated as plain text by renaming it from filename.html to filename.txt. Although this strategy was useful to expert users who could easily understand and manipulate this information, it was often confusing to less technical users, who could accidentally make a file unusable (or «lose» it) by renaming it incorrectly.

This led most versions of Windows and Mac OS to hide the extension when listing files. This prevents the user from accidentally changing the file type, and allows expert users to turn this feature off and display the extensions.

Hiding the extension, however, can create the appearance of two or more identical filenames in the same folder. For example, a company logo may be needed both in .eps format (for publishing) and .png format (for web sites). With the extensions visible, these would appear as the unique filenames: «CompanyLogo.eps» and «CompanyLogo.png«. On the other hand, hiding the extensions would make both appear as «CompanyLogo«, which can lead to confusion.

Hiding extensions can also pose a security risk.^[1] For example, a malicious user could create an executable program with an innocent name such as «Holiday photo.jpg.exe«. The «.exe» would be hidden and an unsuspecting user would see «Holiday photo.jpg«, which would appear to be a JPEG image, usually unable to harm the machine. However, the operating system would still see the «.exe» extension and run the program, which would then be able to cause harm to the computer. The same is true with files with only one extension: as it is not shown to the user, no information about the file can be deduced without explicitly investigating the file. To further trick users, it is possible to store an icon inside the program, in which case some operating systems’ icon assignment for the executable file (.exe) would be overridden with an icon commonly used to represent JPEG images, making the program look like an image. Extensions can also be spoofed: some Microsoft Word macro viruses create a Word file in template format and save it with a .doc extension. Since Word generally ignores extensions and looks at the format of the file, these would open as templates, execute, and spread the virus.^{[citation needed]} This represents a practical problem for Windows systems where extension-hiding is turned on by default.

Internal metadata[edit]

A second way to identify a file format is to use information regarding the format stored inside the file itself, either information meant for this purpose or binary strings that happen to always be in specific locations in files of some formats. Since the easiest place to locate them is at the beginning, such area is usually called a file header when it is greater than a few bytes, or a magic number if it is just a few bytes long.

[edit]

The metadata contained in a file header are usually stored at the start of the file, but might be present in other areas too, often including the end, depending on the file format or the type of data contained. Character-based (text) files usually have character-based headers, whereas binary formats usually have binary headers, although this is not a rule. Text-based file headers usually take up more space, but being human-readable, they can easily be examined by using simple software such as a text editor or a hexadecimal editor.

As well as identifying the file format, file headers may contain metadata about the file and its contents. For example, most image files store information about image format, size, resolution and color space, and optionally authoring information such as who made the image, when and where it was made, what camera model and photographic settings were used (Exif), and so on. Such metadata may be used by software reading or interpreting the file during the loading process and afterwards.

File headers may be used by an operating system to quickly gather information about a file without loading it all into memory, but doing so uses more of a computer’s resources than reading directly from the directory information. For instance, when a graphic file manager has to display the contents of a folder, it must read the headers of many files before it can display the appropriate icons, but these will be located in different places on the storage medium thus taking longer to access. A folder containing many files with complex metadata such as thumbnail information may require considerable time before it can be displayed.

If a header is binary hard-coded such that the header itself needs complex interpretation in order to be recognized, especially for metadata content protection’s sake, there is a risk that the file format can be misinterpreted. It may even have been badly written at the source. This can result in corrupt metadata which, in extremely bad cases, might even render the file unreadable.^{[clarification needed]}

A more complex example of file headers are those used for wrapper (or container) file formats.

Magic number[edit]

One way to incorporate file type metadata, often associated with Unix and its derivatives, is to store a «magic number» inside the file itself. Originally, this term was used for a specific set of 2-byte identifiers at the beginnings of files, but since any binary sequence can be regarded as a number, any feature of a file format which uniquely distinguishes it can be used for identification. GIF images, for instance, always begin with the ASCII representation of either GIF87a or GIF89a, depending upon the standard to which they adhere. Many file types, especially plain-text files, are harder to spot by this method. HTML files, for example, might begin with the string <html> (which is not case sensitive), or an appropriate document type definition that starts with <!DOCTYPE HTML>, or, for XHTML, the XML identifier, which begins with <?xml. The files can also begin with HTML comments, random text, or several empty lines, but still be usable HTML.

The magic number approach offers better guarantees that the format will be identified correctly, and can often determine more precise information about the file. Since reasonably reliable «magic number» tests can be fairly complex, and each file must effectively be tested against every possibility in the magic database, this approach is relatively inefficient, especially for displaying large lists of files (in contrast, file name and metadata-based methods need to check only one piece of data, and match it against a sorted index). Also, data must be read from the file itself, increasing latency as opposed to metadata stored in the directory. Where file types don’t lend themselves to recognition in this way, the system must fall back to metadata. It is, however, the best way for a program to check if the file it has been told to process is of the correct format: while the file’s name or metadata may be altered independently of its content, failing a well-designed magic number test is a pretty sure sign that the file is either corrupt or of the wrong type. On the other hand, a valid magic number does not guarantee that the file is not corrupt or is of a correct type.

So-called shebang lines in script files are a special case of magic numbers. Here, the magic number is human-readable text that identifies a specific command interpreter and options to be passed to the command interpreter.

Another operating system using magic numbers is AmigaOS, where magic numbers were called «Magic Cookies» and were adopted as a standard system to recognize executables in Hunk executable file format and also to let single programs, tools and utilities deal automatically with their saved data files, or any other kind of file types when saving and loading data. This system was then enhanced with the Amiga standard Datatype recognition system. Another method was the FourCC method, originating in OSType on Macintosh, later adapted by Interchange File Format (IFF) and derivatives.

External metadata[edit]

A final way of storing the format of a file is to explicitly store information about the format in the file system, rather than within the file itself.

This approach keeps the metadata separate from both the main data and the name, but is also less portable than either filename extensions or «magic numbers», since the format has to be converted from filesystem to filesystem. While this is also true to an extent with filename extensions— for instance, for compatibility with MS-DOS’s three character limit— most forms of storage have a roughly equivalent definition of a file’s data and name, but may have varying or no representation of further metadata.

Note that zip files or archive files solve the problem of handling metadata. A utility program collects multiple files together along with metadata about each file and the folders/directories they came from all within one new file (e.g. a zip file with extension .zip). The new file is also compressed and possibly encrypted, but now is transmissible as a single file across operating systems by FTP transmissions or sent by email as an attachment. At the destination, the single file received has to be unzipped by a compatible utility to be useful. The problems of handling metadata are solved this way using zip files or archive files.

Mac OS type-codes[edit]

The Mac OS’ Hierarchical File System stores codes for creator and type as part of the directory entry for each file. These codes are referred to as OSTypes. These codes could be any 4-byte sequence but were often selected so that the ASCII representation formed a sequence of meaningful characters, such as an abbreviation of the application’s name or the developer’s initials. For instance a HyperCard «stack» file has a creator of WILD (from Hypercard’s previous name, «WildCard») and a type of STAK. The BBEdit text editor has a creator code of R*ch referring to its original programmer, Rich Siegel. The type code specifies the format of the file, while the creator code specifies the default program to open it with when double-clicked by the user. For example, the user could have several text files all with the type code of TEXT, but each open in a different program, due to having differing creator codes. This feature was intended so that, for example, human-readable plain-text files could be opened in a general-purpose text editor, while programming or HTML code files would open in a specialized editor or IDE. However, this feature was often the source of user confusion, as which program would launch when the files were double-clicked was often unpredictable. RISC OS uses a similar system, consisting of a 12-bit number which can be looked up in a table of descriptions—e.g. the hexadecimal number FF5 is «aliased» to PoScript, representing a PostScript file.

macOS uniform type identifiers (UTIs)[edit]

A Uniform Type Identifier (UTI) is a method used in macOS for uniquely identifying «typed» classes of entities, such as file formats. It was developed by Apple as a replacement for OSType (type & creator codes).

The UTI is a Core Foundation string, which uses a reverse-DNS string. Some common and standard types use a domain called public (e.g. public.png for a Portable Network Graphics image), while other domains can be used for third-party types (e.g. com.adobe.pdf for Portable Document Format). UTIs can be defined within a hierarchical structure, known as a conformance hierarchy. Thus, public.png conforms to a supertype of public.image, which itself conforms to a supertype of public.data. A UTI can exist in multiple hierarchies, which provides great flexibility.

In addition to file formats, UTIs can also be used for other entities which can exist in macOS, including:

• Pasteboard data
• Folders (directories)
• Translatable types (as handled by the Translation Manager)
• Bundles
• Frameworks
• Streaming data
• Aliases and symlinks

OS/2 extended attributes[edit]

The HPFS, FAT12, and FAT16 (but not FAT32) filesystems allow the storage of «extended attributes» with files. These comprise an arbitrary set of triplets with a name, a coded type for the value, and a value, where the names are unique and values can be up to 64 KB long. There are standardized meanings for certain types and names (under OS/2). One such is that the «.TYPE» extended attribute is used to determine the file type. Its value comprises a list of one or more file types associated with the file, each of which is a string, such as «Plain Text» or «HTML document». Thus a file may have several types.

The NTFS filesystem also allows storage of OS/2 extended attributes, as one of the file forks, but this feature is merely present to support the OS/2 subsystem (not present in XP), so the Win32 subsystem treats this information as an opaque block of data and does not use it. Instead, it relies on other file forks to store meta-information in Win32-specific formats. OS/2 extended attributes can still be read and written by Win32 programs, but the data must be entirely parsed by applications.

POSIX extended attributes[edit]

On Unix and Unix-like systems, the ext2, ext3, ext4, ReiserFS version 3, XFS, JFS, FFS, and HFS+ filesystems allow the storage of extended attributes with files. These include an arbitrary list of «name=value» strings, where the names are unique and a value can be accessed through its related name.

PRONOM unique identifiers (PUIDs)[edit]

The PRONOM Persistent Unique Identifier (PUID) is an extensible scheme of persistent, unique, and unambiguous identifiers for file formats, which has been developed by The National Archives of the UK as part of its PRONOM technical registry service. PUIDs can be expressed as Uniform Resource Identifiers using the info:pronom/ namespace. Although not yet widely used outside of the UK government and some digital preservation programs, the PUID scheme does provide greater granularity than most alternative schemes.

MIME types[edit]

MIME types are widely used in many Internet-related applications, and increasingly elsewhere, although their usage for on-disc type information is rare. These consist of a standardised system of identifiers (managed by IANA) consisting of a type and a sub-type, separated by a slash—for instance, text/html or image/gif. These were originally intended as a way of identifying what type of file was attached to an e-mail, independent of the source and target operating systems. MIME types identify files on BeOS, AmigaOS 4.0 and MorphOS, as well as store unique application signatures for application launching. In AmigaOS and MorphOS, the Mime type system works in parallel with Amiga specific Datatype system.

There are problems with the MIME types though; several organizations and people have created their own MIME types without registering them properly with IANA, which makes the use of this standard awkward in some cases.

File format identifiers (FFIDs)[edit]

File format identifiers are another, not widely used way to identify file formats according to their origin and their file category. It was created for the Description Explorer suite of software. It is composed of several digits of the form NNNNNNNNN-XX-YYYYYYY. The first part indicates the organization origin/maintainer (this number represents a value in a company/standards organization database), and the 2 following digits categorize the type of file in hexadecimal. The final part is composed of the usual filename extension of the file or the international standard number of the file, padded left with zeros. For example, the PNG file specification has the FFID of 000000001-31-0015948 where 31 indicates an image file, 0015948 is the standard number and 000000001 indicates the International Organization for Standardization (ISO).

File content based format identification[edit]

Another but less popular way to identify the file format is to examine the file contents for distinguishable patterns among file types. The contents of a file are a sequence of bytes and a byte has 256 unique permutations (0–255). Thus, counting the occurrence of byte patterns that is often referred to as byte frequency distribution gives distinguishable patterns to identify file types. There are many content-based file type identification schemes that use a byte frequency distribution to build the representative models for file type and use any statistical and data mining techniques to identify file types^[2]

File structure[edit]

There are several types of ways to structure data in a file. The most usual ones are described below.

Unstructured formats (raw memory dumps)[edit]

Earlier file formats used raw data formats that consisted of directly dumping the memory images of one or more structures into the file.

This has several drawbacks. Unless the memory images also have reserved spaces for future extensions, extending and improving this type of structured file is very difficult. It also creates files that might be specific to one platform or programming language (for example a structure containing a Pascal string is not recognized as such in C). On the other hand, developing tools for reading and writing these types of files is very simple.

The limitations of the unstructured formats led to the development of other types of file formats that could be easily extended and be backward compatible at the same time.

Chunk-based formats[edit]

In this kind of file structure, each piece of data is embedded in a container that somehow identifies the data. The container’s scope can be identified by start- and end-markers of some kind, by an explicit length field somewhere, or by fixed requirements of the file format’s definition.

Throughout the 1970s, many programs used formats of this general kind. For example, word-processors such as troff, Script, and Scribe, and database export files such as CSV. Electronic Arts and Commodore-Amiga also used this type of file format in 1985, with their IFF (Interchange File Format) file format.

A container is sometimes called a «chunk», although «chunk» may also imply that each piece is small, and/or that chunks do not contain other chunks; many formats do not impose those requirements.

The information that identifies a particular «chunk» may be called many different things, often terms including «field name», «identifier», «label», or «tag». The identifiers are often human-readable, and classify parts of the data: for example, as a «surname», «address», «rectangle», «font name», etc. These are not the same thing as identifiers in the sense of a database key or serial number (although an identifier may well identify its associated data as such a key).

With this type of file structure, tools that do not know certain chunk identifiers simply skip those that they do not understand. Depending on the
actual meaning of the skipped data, this may or may not be useful (CSS explicitly defines such behavior).

This concept has been used again and again by RIFF (Microsoft-IBM equivalent of IFF), PNG, JPEG storage, DER (Distinguished Encoding Rules) encoded streams and files (which were originally described in CCITT X.409:1984 and therefore predate IFF), and Structured Data Exchange Format (SDXF).

Indeed, any data format must somehow identify the significance of its component parts, and embedded boundary-markers are an obvious way to do so:

• MIME headers do this with a colon-separated label at the start of each logical line. MIME headers cannot contain other MIME headers, though the data content of some headers has sub-parts that can be extracted by other conventions.
• CSV and similar files often do this using a header records with field names, and with commas to mark the field boundaries. Like MIME, CSV has no provision for structures with more than one level.
• XML and its kin can be loosely considered a kind of chunk-based format, since data elements are identified by markup that is akin to chunk identifiers. However, it has formal advantages such as schemas and validation, as well as the ability to represent more complex structures such as trees, DAGs, and charts. If XML is considered a «chunk» format, then SGML and its predecessor IBM GML are among the earliest examples of such formats.
• JSON is similar to XML without schemas, cross-references, or a definition for the meaning of repeated field-names, and is often convenient for programmers.
• YAML is similar to JSON, but use indentation to separate data chunks and aim to be more human-readable than JSON or XML.
• Protocol Buffers are in turn similar to JSON, notably replacing boundary-markers in the data with field numbers, which are mapped to/from names by some external mechanism.

Directory-based formats[edit]

This is another extensible format, that closely resembles a file system (OLE Documents are actual filesystems), where the file is composed of ‘directory entries’ that contain the location of the data within the file itself as well as its signatures (and in certain cases its type). Good examples of these types of file structures are disk images, executables, OLE documents TIFF, libraries.

Some file formats like ODT and DOCX, being PKZIP-based, are both chunked and carry a directory.^{[citation needed]}

The structure of a directory-based file format lends itself to modifications more easily than unstructured or chunk-based formats.^{[citation needed]} The nature of this type of format allows users to carefully construct files that causes reader software to do things the authors of the format never intended to happen. An example of this is the zip bomb. Directory-based file formats also use values that point at other areas in the file but if some later data value points back at data that was read earlier, it can result in an infinite loop for any reader software that assumes the input file is valid and blindly follows the loop.^{[citation needed]}

See also[edit]

• Audio file format
• Chemical file format
• Comparison of executable file formats
• Digital container format
• Document file format
• DROID file format identification utility
• File (command), a file type identification utility
• File conversion
• Future proofing
• Graphics file format summary
• Image file formats
• List of archive formats
• List of file formats
• List of file signatures, or «magic numbers»
• List of filename extensions (alphabetical)
• List of free file formats
• List of motion and gesture file formats
• Magic number (programming)
• Object file
• Video file format
• Windows file types
• Filename extension

References[edit]

External links[edit]

• File format at Curlie
• Best Practices for File Formats, US: Stanford University Libraries, Data Management Services («The file formats you use have a direct impact on your ability to open those files at a later date and on the ability of other people to access those data»)

A file format is a standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary or free.

Some file formats are designed for very particular types of data: PNG files, for example, store bitmapped images using lossless data compression. Other file formats, however, are designed for storage of several different types of data: the Ogg format can act as a container for different types of multimedia including any combination of audio and video, with or without text (such as subtitles), and metadata. A text file can contain any stream of characters, including possible control characters, and is encoded in one of various character encoding schemes. Some file formats, such as HTML, scalable vector graphics, and the source code of computer software are text files with defined syntaxes that allow them to be used for specific purposes.

Specifications[edit]

File formats often have a published specification describing the encoding method and enabling testing of program intended functionality. Not all formats have freely available specification documents, partly because some developers view their specification documents as trade secrets, and partly because other developers never author a formal specification document, letting precedent set by other already existing programs that use the format define the format via how these existing programs use it.

If the developer of a format doesn’t publish free specifications, another developer looking to utilize that kind of file must either reverse engineer the file to find out how to read it or acquire the specification document from the format’s developers for a fee and by signing a non-disclosure agreement. The latter approach is possible only when a formal specification document exists. Both strategies require significant time, money, or both; therefore, file formats with publicly available specifications tend to be supported by more programs.

Patents[edit]

Patent law, rather than copyright, is more often used to protect a file format. Although patents for file formats are not directly permitted under US law, some formats encode data using patented algorithms. For example, using compression with the GIF file format requires the use of a patented algorithm, and though the patent owner did not initially enforce their patent, they later began collecting royalty fees. This has resulted in a significant decrease in the use of GIFs, and is partly responsible for the development of the alternative PNG format. However, the GIF patent expired in the US in mid-2003, and worldwide in mid-2004.

Identifying file type[edit]

Different operating systems have traditionally taken different approaches to determining a particular file’s format, with each approach having its own advantages and disadvantages. Most modern operating systems and individual applications need to use all of the following approaches to read «foreign» file formats, if not work with them completely.

Filename extension[edit]

One popular method used by many operating systems, including Windows, macOS, CP/M, DOS, VMS, and VM/CMS, is to determine the format of a file based on the end of its name, more specifically the letters following the final period. This portion of the filename is known as the filename extension. For example, HTML documents are identified by names that end with .html (or .htm), and GIF images by .gif. In the original FAT file system, file names were limited to an eight-character identifier and a three-character extension, known as an 8.3 filename. There are a limited number of three-letter extensions, which can cause a given extension to be used by more than one program. Many formats still use three-character extensions even though modern operating systems and application programs no longer have this limitation. Since there is no standard list of extensions, more than one format can use the same extension, which can confuse both the operating system and users.

One artifact of this approach is that the system can easily be tricked into treating a file as a different format simply by renaming it — an HTML file can, for instance, be easily treated as plain text by renaming it from filename.html to filename.txt. Although this strategy was useful to expert users who could easily understand and manipulate this information, it was often confusing to less technical users, who could accidentally make a file unusable (or «lose» it) by renaming it incorrectly.

This led most versions of Windows and Mac OS to hide the extension when listing files. This prevents the user from accidentally changing the file type, and allows expert users to turn this feature off and display the extensions.

Hiding the extension, however, can create the appearance of two or more identical filenames in the same folder. For example, a company logo may be needed both in .eps format (for publishing) and .png format (for web sites). With the extensions visible, these would appear as the unique filenames: «CompanyLogo.eps» and «CompanyLogo.png«. On the other hand, hiding the extensions would make both appear as «CompanyLogo«, which can lead to confusion.

Hiding extensions can also pose a security risk.^[1] For example, a malicious user could create an executable program with an innocent name such as «Holiday photo.jpg.exe«. The «.exe» would be hidden and an unsuspecting user would see «Holiday photo.jpg«, which would appear to be a JPEG image, usually unable to harm the machine. However, the operating system would still see the «.exe» extension and run the program, which would then be able to cause harm to the computer. The same is true with files with only one extension: as it is not shown to the user, no information about the file can be deduced without explicitly investigating the file. To further trick users, it is possible to store an icon inside the program, in which case some operating systems’ icon assignment for the executable file (.exe) would be overridden with an icon commonly used to represent JPEG images, making the program look like an image. Extensions can also be spoofed: some Microsoft Word macro viruses create a Word file in template format and save it with a .doc extension. Since Word generally ignores extensions and looks at the format of the file, these would open as templates, execute, and spread the virus.^{[citation needed]} This represents a practical problem for Windows systems where extension-hiding is turned on by default.

Internal metadata[edit]

A second way to identify a file format is to use information regarding the format stored inside the file itself, either information meant for this purpose or binary strings that happen to always be in specific locations in files of some formats. Since the easiest place to locate them is at the beginning, such area is usually called a file header when it is greater than a few bytes, or a magic number if it is just a few bytes long.

[edit]

The metadata contained in a file header are usually stored at the start of the file, but might be present in other areas too, often including the end, depending on the file format or the type of data contained. Character-based (text) files usually have character-based headers, whereas binary formats usually have binary headers, although this is not a rule. Text-based file headers usually take up more space, but being human-readable, they can easily be examined by using simple software such as a text editor or a hexadecimal editor.

As well as identifying the file format, file headers may contain metadata about the file and its contents. For example, most image files store information about image format, size, resolution and color space, and optionally authoring information such as who made the image, when and where it was made, what camera model and photographic settings were used (Exif), and so on. Such metadata may be used by software reading or interpreting the file during the loading process and afterwards.

File headers may be used by an operating system to quickly gather information about a file without loading it all into memory, but doing so uses more of a computer’s resources than reading directly from the directory information. For instance, when a graphic file manager has to display the contents of a folder, it must read the headers of many files before it can display the appropriate icons, but these will be located in different places on the storage medium thus taking longer to access. A folder containing many files with complex metadata such as thumbnail information may require considerable time before it can be displayed.

If a header is binary hard-coded such that the header itself needs complex interpretation in order to be recognized, especially for metadata content protection’s sake, there is a risk that the file format can be misinterpreted. It may even have been badly written at the source. This can result in corrupt metadata which, in extremely bad cases, might even render the file unreadable.^{[clarification needed]}

A more complex example of file headers are those used for wrapper (or container) file formats.

Magic number[edit]

One way to incorporate file type metadata, often associated with Unix and its derivatives, is to store a «magic number» inside the file itself. Originally, this term was used for a specific set of 2-byte identifiers at the beginnings of files, but since any binary sequence can be regarded as a number, any feature of a file format which uniquely distinguishes it can be used for identification. GIF images, for instance, always begin with the ASCII representation of either GIF87a or GIF89a, depending upon the standard to which they adhere. Many file types, especially plain-text files, are harder to spot by this method. HTML files, for example, might begin with the string <html> (which is not case sensitive), or an appropriate document type definition that starts with <!DOCTYPE HTML>, or, for XHTML, the XML identifier, which begins with <?xml. The files can also begin with HTML comments, random text, or several empty lines, but still be usable HTML.

The magic number approach offers better guarantees that the format will be identified correctly, and can often determine more precise information about the file. Since reasonably reliable «magic number» tests can be fairly complex, and each file must effectively be tested against every possibility in the magic database, this approach is relatively inefficient, especially for displaying large lists of files (in contrast, file name and metadata-based methods need to check only one piece of data, and match it against a sorted index). Also, data must be read from the file itself, increasing latency as opposed to metadata stored in the directory. Where file types don’t lend themselves to recognition in this way, the system must fall back to metadata. It is, however, the best way for a program to check if the file it has been told to process is of the correct format: while the file’s name or metadata may be altered independently of its content, failing a well-designed magic number test is a pretty sure sign that the file is either corrupt or of the wrong type. On the other hand, a valid magic number does not guarantee that the file is not corrupt or is of a correct type.

So-called shebang lines in script files are a special case of magic numbers. Here, the magic number is human-readable text that identifies a specific command interpreter and options to be passed to the command interpreter.

Another operating system using magic numbers is AmigaOS, where magic numbers were called «Magic Cookies» and were adopted as a standard system to recognize executables in Hunk executable file format and also to let single programs, tools and utilities deal automatically with their saved data files, or any other kind of file types when saving and loading data. This system was then enhanced with the Amiga standard Datatype recognition system. Another method was the FourCC method, originating in OSType on Macintosh, later adapted by Interchange File Format (IFF) and derivatives.

External metadata[edit]

A final way of storing the format of a file is to explicitly store information about the format in the file system, rather than within the file itself.

This approach keeps the metadata separate from both the main data and the name, but is also less portable than either filename extensions or «magic numbers», since the format has to be converted from filesystem to filesystem. While this is also true to an extent with filename extensions— for instance, for compatibility with MS-DOS’s three character limit— most forms of storage have a roughly equivalent definition of a file’s data and name, but may have varying or no representation of further metadata.

Note that zip files or archive files solve the problem of handling metadata. A utility program collects multiple files together along with metadata about each file and the folders/directories they came from all within one new file (e.g. a zip file with extension .zip). The new file is also compressed and possibly encrypted, but now is transmissible as a single file across operating systems by FTP transmissions or sent by email as an attachment. At the destination, the single file received has to be unzipped by a compatible utility to be useful. The problems of handling metadata are solved this way using zip files or archive files.

Mac OS type-codes[edit]

The Mac OS’ Hierarchical File System stores codes for creator and type as part of the directory entry for each file. These codes are referred to as OSTypes. These codes could be any 4-byte sequence but were often selected so that the ASCII representation formed a sequence of meaningful characters, such as an abbreviation of the application’s name or the developer’s initials. For instance a HyperCard «stack» file has a creator of WILD (from Hypercard’s previous name, «WildCard») and a type of STAK. The BBEdit text editor has a creator code of R*ch referring to its original programmer, Rich Siegel. The type code specifies the format of the file, while the creator code specifies the default program to open it with when double-clicked by the user. For example, the user could have several text files all with the type code of TEXT, but each open in a different program, due to having differing creator codes. This feature was intended so that, for example, human-readable plain-text files could be opened in a general-purpose text editor, while programming or HTML code files would open in a specialized editor or IDE. However, this feature was often the source of user confusion, as which program would launch when the files were double-clicked was often unpredictable. RISC OS uses a similar system, consisting of a 12-bit number which can be looked up in a table of descriptions—e.g. the hexadecimal number FF5 is «aliased» to PoScript, representing a PostScript file.

macOS uniform type identifiers (UTIs)[edit]

A Uniform Type Identifier (UTI) is a method used in macOS for uniquely identifying «typed» classes of entities, such as file formats. It was developed by Apple as a replacement for OSType (type & creator codes).

The UTI is a Core Foundation string, which uses a reverse-DNS string. Some common and standard types use a domain called public (e.g. public.png for a Portable Network Graphics image), while other domains can be used for third-party types (e.g. com.adobe.pdf for Portable Document Format). UTIs can be defined within a hierarchical structure, known as a conformance hierarchy. Thus, public.png conforms to a supertype of public.image, which itself conforms to a supertype of public.data. A UTI can exist in multiple hierarchies, which provides great flexibility.

In addition to file formats, UTIs can also be used for other entities which can exist in macOS, including:

• Pasteboard data
• Folders (directories)
• Translatable types (as handled by the Translation Manager)
• Bundles
• Frameworks
• Streaming data
• Aliases and symlinks

OS/2 extended attributes[edit]

The HPFS, FAT12, and FAT16 (but not FAT32) filesystems allow the storage of «extended attributes» with files. These comprise an arbitrary set of triplets with a name, a coded type for the value, and a value, where the names are unique and values can be up to 64 KB long. There are standardized meanings for certain types and names (under OS/2). One such is that the «.TYPE» extended attribute is used to determine the file type. Its value comprises a list of one or more file types associated with the file, each of which is a string, such as «Plain Text» or «HTML document». Thus a file may have several types.

The NTFS filesystem also allows storage of OS/2 extended attributes, as one of the file forks, but this feature is merely present to support the OS/2 subsystem (not present in XP), so the Win32 subsystem treats this information as an opaque block of data and does not use it. Instead, it relies on other file forks to store meta-information in Win32-specific formats. OS/2 extended attributes can still be read and written by Win32 programs, but the data must be entirely parsed by applications.

POSIX extended attributes[edit]

On Unix and Unix-like systems, the ext2, ext3, ext4, ReiserFS version 3, XFS, JFS, FFS, and HFS+ filesystems allow the storage of extended attributes with files. These include an arbitrary list of «name=value» strings, where the names are unique and a value can be accessed through its related name.

PRONOM unique identifiers (PUIDs)[edit]

The PRONOM Persistent Unique Identifier (PUID) is an extensible scheme of persistent, unique, and unambiguous identifiers for file formats, which has been developed by The National Archives of the UK as part of its PRONOM technical registry service. PUIDs can be expressed as Uniform Resource Identifiers using the info:pronom/ namespace. Although not yet widely used outside of the UK government and some digital preservation programs, the PUID scheme does provide greater granularity than most alternative schemes.

MIME types[edit]

MIME types are widely used in many Internet-related applications, and increasingly elsewhere, although their usage for on-disc type information is rare. These consist of a standardised system of identifiers (managed by IANA) consisting of a type and a sub-type, separated by a slash—for instance, text/html or image/gif. These were originally intended as a way of identifying what type of file was attached to an e-mail, independent of the source and target operating systems. MIME types identify files on BeOS, AmigaOS 4.0 and MorphOS, as well as store unique application signatures for application launching. In AmigaOS and MorphOS, the Mime type system works in parallel with Amiga specific Datatype system.

There are problems with the MIME types though; several organizations and people have created their own MIME types without registering them properly with IANA, which makes the use of this standard awkward in some cases.

File format identifiers (FFIDs)[edit]

File format identifiers are another, not widely used way to identify file formats according to their origin and their file category. It was created for the Description Explorer suite of software. It is composed of several digits of the form NNNNNNNNN-XX-YYYYYYY. The first part indicates the organization origin/maintainer (this number represents a value in a company/standards organization database), and the 2 following digits categorize the type of file in hexadecimal. The final part is composed of the usual filename extension of the file or the international standard number of the file, padded left with zeros. For example, the PNG file specification has the FFID of 000000001-31-0015948 where 31 indicates an image file, 0015948 is the standard number and 000000001 indicates the International Organization for Standardization (ISO).

File content based format identification[edit]

Another but less popular way to identify the file format is to examine the file contents for distinguishable patterns among file types. The contents of a file are a sequence of bytes and a byte has 256 unique permutations (0–255). Thus, counting the occurrence of byte patterns that is often referred to as byte frequency distribution gives distinguishable patterns to identify file types. There are many content-based file type identification schemes that use a byte frequency distribution to build the representative models for file type and use any statistical and data mining techniques to identify file types^[2]

File structure[edit]

There are several types of ways to structure data in a file. The most usual ones are described below.

Unstructured formats (raw memory dumps)[edit]

Earlier file formats used raw data formats that consisted of directly dumping the memory images of one or more structures into the file.

This has several drawbacks. Unless the memory images also have reserved spaces for future extensions, extending and improving this type of structured file is very difficult. It also creates files that might be specific to one platform or programming language (for example a structure containing a Pascal string is not recognized as such in C). On the other hand, developing tools for reading and writing these types of files is very simple.

The limitations of the unstructured formats led to the development of other types of file formats that could be easily extended and be backward compatible at the same time.

Chunk-based formats[edit]

In this kind of file structure, each piece of data is embedded in a container that somehow identifies the data. The container’s scope can be identified by start- and end-markers of some kind, by an explicit length field somewhere, or by fixed requirements of the file format’s definition.

Throughout the 1970s, many programs used formats of this general kind. For example, word-processors such as troff, Script, and Scribe, and database export files such as CSV. Electronic Arts and Commodore-Amiga also used this type of file format in 1985, with their IFF (Interchange File Format) file format.

A container is sometimes called a «chunk», although «chunk» may also imply that each piece is small, and/or that chunks do not contain other chunks; many formats do not impose those requirements.

The information that identifies a particular «chunk» may be called many different things, often terms including «field name», «identifier», «label», or «tag». The identifiers are often human-readable, and classify parts of the data: for example, as a «surname», «address», «rectangle», «font name», etc. These are not the same thing as identifiers in the sense of a database key or serial number (although an identifier may well identify its associated data as such a key).

With this type of file structure, tools that do not know certain chunk identifiers simply skip those that they do not understand. Depending on the
actual meaning of the skipped data, this may or may not be useful (CSS explicitly defines such behavior).

This concept has been used again and again by RIFF (Microsoft-IBM equivalent of IFF), PNG, JPEG storage, DER (Distinguished Encoding Rules) encoded streams and files (which were originally described in CCITT X.409:1984 and therefore predate IFF), and Structured Data Exchange Format (SDXF).

Indeed, any data format must somehow identify the significance of its component parts, and embedded boundary-markers are an obvious way to do so:

• MIME headers do this with a colon-separated label at the start of each logical line. MIME headers cannot contain other MIME headers, though the data content of some headers has sub-parts that can be extracted by other conventions.
• CSV and similar files often do this using a header records with field names, and with commas to mark the field boundaries. Like MIME, CSV has no provision for structures with more than one level.
• XML and its kin can be loosely considered a kind of chunk-based format, since data elements are identified by markup that is akin to chunk identifiers. However, it has formal advantages such as schemas and validation, as well as the ability to represent more complex structures such as trees, DAGs, and charts. If XML is considered a «chunk» format, then SGML and its predecessor IBM GML are among the earliest examples of such formats.
• JSON is similar to XML without schemas, cross-references, or a definition for the meaning of repeated field-names, and is often convenient for programmers.
• YAML is similar to JSON, but use indentation to separate data chunks and aim to be more human-readable than JSON or XML.
• Protocol Buffers are in turn similar to JSON, notably replacing boundary-markers in the data with field numbers, which are mapped to/from names by some external mechanism.

Directory-based formats[edit]

This is another extensible format, that closely resembles a file system (OLE Documents are actual filesystems), where the file is composed of ‘directory entries’ that contain the location of the data within the file itself as well as its signatures (and in certain cases its type). Good examples of these types of file structures are disk images, executables, OLE documents TIFF, libraries.

Some file formats like ODT and DOCX, being PKZIP-based, are both chunked and carry a directory.^{[citation needed]}

The structure of a directory-based file format lends itself to modifications more easily than unstructured or chunk-based formats.^{[citation needed]} The nature of this type of format allows users to carefully construct files that causes reader software to do things the authors of the format never intended to happen. An example of this is the zip bomb. Directory-based file formats also use values that point at other areas in the file but if some later data value points back at data that was read earlier, it can result in an infinite loop for any reader software that assumes the input file is valid and blindly follows the loop.^{[citation needed]}

See also[edit]

• Audio file format
• Chemical file format
• Comparison of executable file formats
• Digital container format
• Document file format
• DROID file format identification utility
• File (command), a file type identification utility
• File conversion
• Future proofing
• Graphics file format summary
• Image file formats
• List of archive formats
• List of file formats
• List of file signatures, or «magic numbers»
• List of filename extensions (alphabetical)
• List of free file formats
• List of motion and gesture file formats
• Magic number (programming)
• Object file
• Video file format
• Windows file types
• Filename extension

References[edit]

External links[edit]

• File format at Curlie
• Best Practices for File Formats, US: Stanford University Libraries, Data Management Services («The file formats you use have a direct impact on your ability to open those files at a later date and on the ability of other people to access those data»)

Расширение файла

В этом уроке я расскажу, что такое расширение и какие бывают типы файлов в Windows. А в конце дам таблицу наиболее популярных форматов с подробным описанием.

Что такое формат и расширение

Формат или тип — это информация о файле, по которой система понимает, какого он вида и в какой программе его открыть. Для этого у каждого файла есть расширение.

Расширение — это несколько английских букв и/или цифр. Находятся они сразу после названия и разделяются точкой.

На картинке показан файл с расширением mp3. Про него компьютер знает, что это аудио и открывать его нужно в программе-проигрывателе. Значок, которым он отмечен – это иконка программы запуска.

Есть текстовые файлы — они открываются в программе для работы с текстом. Есть музыкальные и видео — они запускаются в проигрывателях. Есть графические (фото, картинки) – они открываются в программах для просмотра изображений. И еще много других типов. У каждого из них свой значок, точнее, значок приложения, в котором он будет открыт.

Если у файла вместо иконки белый лист, значит, компьютер не подобрал для него подходящую программу.

При его открытии появится окно с выбором приложения. Компьютер предлагает пользователю самостоятельно указать программу для запуска.

На заметку. В Windows есть разнообразные системные иконки:

Как правило, такими значками отмечены файлы, которые нужны для корректной работы компьютера. Их много в системном локальном диске. Такие объекты нельзя удалять или переименовывать, иначе приложения, за которые они отвечают, могут работать со сбоями.

Как узнать расширение

Система компьютера может быть настроена таким образом, что расширения у всех файлов показаны.

Или наоборот: так, что показаны только имена, без форматов.

Эту настройку можно изменить.

В Windows 10 открыть любую папку, нажать на пункт «Вид» вверху и поставить или убрать птичку с пункта «Расширения имен файлов».

Или так: Вид → Параметры → вкладка «Вид» → пункт «Скрывать расширения для зарегистрированных типов файлов».

В Windows 7 чуть сложнее:

1. Открыть любую папку.
2. Нажать на «Упорядочить значки» вверху.
3. Выбрать «Параметры папок и поиска».
4. В появившемся окошке перейти на вкладку «Вид».
5. Внизу списка поставить или убрать галочку с пункта «Скрывать расширения для зарегистрированных типов файлов».

Или так: Пуск → Панель управления → Оформление и персонализация → Параметры папок.

Если расширения нет

Если у объекта нет расширения, компьютер не может подобрать программу для его запуска. Это происходит, когда пользователь случайно или намеренно удаляет расширение из имени. А еще может быть из-за вируса.

Решить эту проблему легко, если знаешь тип объекта. Например, знаешь, что это фотография. Тогда нужно просто переименовать файл, добавить после названия точку и указать формат. Вот как это сделать:

1. Настроить компьютер на показ расширений (см. выше).
2. Правой кнопкой мыши по файлу – Переименовать.
3. Сразу после названия напечатать точку и расширение.
4. Нажать Enter.

Наиболее популярные форматы:

• Документы – doc, docx или pdf
• Таблицы – xls, xlsx
• Архивы – zip или rar
• Фотографии – jpg или png
• Музыка – mp3 или wav
• Видео – mp4 или avi

Другие типы можно посмотреть в конце урока в таблице.

Если формат неизвестен. Чтобы открыть файл, необязательно вручную прописывать расширение. Можно просто запустить его и в окошке выбрать подходящую программу. Если вы правильно ее укажите, объект откроется.

Или щелкните по нему правой кнопкой мыши, выберите «Открыть с помощью…». Или «Открыть с помощью» → «Выбрать другое приложение».

Узнать тип файла можно через сервис open-file.ru. Просто перетяните объект в окошко, и сайт определит формат.

Как изменить расширение

Изменить расширение можно через переименование:

1. Настроить компьютер на показ расширений (см. выше).
2. Щелкнуть правой кнопкой мыши по файлу – Переименовать.
3. Стереть старое расширение после точки и напечатать новое.
4. Нажать Enter.

Появится окошко, в котором система предупредит о последствиях. Ведь если вы неправильно укажите формат, файл может не открыться. Например, у вас документ с расширением doc, а вы меняете его на pdf.

После нажатия на кнопку «Да» новый тип будет назначен. А также добавится значок программы для его запуска. Но обычно после такой ручной смены расширения файл перестает открываться. Потому что он технически остался тем же, что и был.

Вернуть старое расширение можно таким же образом – через переименование. Или щелкнув правой кнопкой мыши по пустому месту и выбрав пункт «Отменить переименование».

Так как же правильно изменить расширение? Для этого нужно сделать конвертацию – преобразование в другой формат. Это делается через специальные программы или онлайн-сервисы.

Вбиваем в поисковик Яндекс или Гугл запрос «из … в …». Например, из word в pdf.

В моем случае Яндекс предложил несколько онлайн сервисов. Все они интуитивно понятны: загружаем документ на сайт → сервис преобразовывает его в pdf → скачиваем результат на компьютер.

Но в некоторых случаях лучше использовать программу. Например, если нужно конвертировать видео большого размера.

Как назначить программу запуска

Каждому типу файла система назначает приложение для его запуска. И помечает иконкой этой программы. Например, текстовые (txt) будут по умолчанию открыты в Блокноте. А музыкальные (mp3) – в проигрывателе Windows Media.

Когда вместо значка показан белый лист, значит, система не понимает, в какой программе открыть объект. И при его запуске предлагает самостоятельно выбрать приложение из тех, что установлены на компьютере.

Если поставить птичку на пункт «Всегда использовать это приложение», то в последующем все объекты данного типа будут запускаться в выбранной программе.

Но не всегда нужная программа установлена на компьютере. Бывает, ее просто нет — тогда файл открыть никак не получится. В этом случае нужно установить подходящее приложение.

Для каждого популярного формата есть своя бесплатная программа:

• PDF – Foxit Reader (оф.сайт)
• ZIP и RAR – 7-Zip (оф.сайт)
• DOC, DOCX, XLS, XLSX и другие документы MS Office – OpenOffice (оф.сайт)
• MP3, MP4, MKV и другие аудио/видео – Media Player Classic (оф.сайт)

Другие форматы и программы для них смотрите в таблице.

На заметку. Также белый лист вместо значка приложения показывается на файлах, у которых нет расширения. Об этом я рассказывал выше в статье.

Выбор программы по умолчанию

А бывает, объекты определенного типа открываются в неподходящей программе. Тогда можно указать другое приложение для их запуска.

1. Щелкните правой кнопкой мыши по файлу. Выберите «Открыть с помощью…» или «Открыть с помощью» → «Выбрать другое приложение».

2. В окошке кликните левой кнопкой мыши по нужной программе и поставьте птичку на пункт «Всегда использовать это приложение». Нажмите ОК.

Вот и всё – теперь объекты данного формата будут по умолчанию запускаться в назначенной программе.

Таблица популярных форматов

Расширение	Тип файла	Программа
.jpg .png .bmp .gif .tif	Изображение	Фотографии (Windows 8/10) Средство просмотра фотографий (Windows 7) FastStone Image Viewer Paint
.doc .docx	Документ	Microsoft Word OpenOffice LibreOffice
.xls .xlsx	Электронная таблица	Microsoft Excel OpenOffice LibreOffice
.pdf	PDF-документ	Acrobat Reader Foxit Reader
.txt	Текстовый файл	Блокнот Notepad++
.zip .rar .7z .gzip	Архив	WinZip WinRAR 7-Zip
.mp3 .wav .midi .aac	Аудиофайл	Windows Media Player Media Player Classic VLC Media Player
.mp4 .avi .mkv .wmv .flv .mpeg	Видеофайл	Windows Media Player Media Player Classic VLC Media Player
.html .htm .mht	Cтраница из интернета	Google Chrome Яндекс.Браузер Mozilla Firefox Opera
.ppt .pptx	Презентация	Microsoft PowerPoint OpenOffice
.mdb .accdb	База данных	Microsoft Access
.iso	Образ оптического диска	UltraISO Alcohol 120% 7-Zip
.cdr	Векторное изображение	CorelDRAW CDR Viewer
.torrent	Торрент-файл	uTorrent BitTorrent
.djvu	Сканированный документ (книга, журнал и пр.)	WinDjView
.fb2 .epub .mobi	Электронная книга	FBReader

Имена файлов в Windows состоять из двух частей, разделенных точкой: первая, имя файла, и вторая, расширение из трех или четырех символов, которое определяет тип файла. Например, в expenses.xlsx первая часть имени файла — expenses, а расширение — xlsx.

Расширения помогают определить компьютеру, в каком приложении был создан файл или в каком приложении его можно открыть, а также какой значок следует использовать для файла. Например, расширение docx сообщает компьютеру, что файл можно открыть в программе Microsoft Word и что при просмотре файла в проводнике для него следует отображать значок Word.

Большинство расширений имен файлов совместимы с более чем одной программой. Можно изменить расширение имени файла, но при этом файл не будет преобразован либо изменен как-либо еще, за исключением изменения имени файла. Дополнительные инструкции по изменению программы для открытия файла см. в разделе Изменение программ по умолчанию в Windows 10.

Если при просмотре файлов в проводнике не отображаются расширения имен файлов, выполните следующие действия.

1. В поле поиска на панели задач введите слово проводник и в результатах поиска выберите Проводник.

2. В проводнике в разделе Вид в группе Показать или скрыть установите флажок Расширения имен файлов.

   

Ниже приведен список распространенных расширений имен и форматов файлов в Windows.

Расширение	Формат
aac, adt, adts	Файл аудио Windows
accdb	Файл базы данных Microsoft Access
accde	Файл Microsoft Access только для выполнения
accdr	База данных Microsoft Access
accdt	Шаблон базы данных Microsoft Access
aif, aifc, aiff	Звуковой файл Audio Interchange File Format
aspx	Файл Active Server Page ASP.NET
avi	Файл аудио или видео Audio Video Interleave
bat	Пакетный файл PC
bin	Двоичный сжатый файл
bmp	Файл точечного рисунка
cab	CAB-файл Windows
cda	Дорожка компакт-диска
csv	Файл данных с разделителями-запятыми
dif	Файл таблицы формата DIF
dll	Файл динамической библиотеки
doc	Документ Microsoft Word до Word 2007
docm	Документ Microsoft Word с включенной поддержкой макросов
docx	Документ Microsoft Word
dot	Шаблон Microsoft Word до Word 2007
dotx	Шаблон Microsoft Word
eml	Файл электронной почты, созданный в приложениях Outlook Express, «Почта Windows Live» и других программах
eps	Файл Encapsulated PostScript
exe	Исполняемый файл программы
flv	Видеофайл совместимый с Flash
gif	Файл Graphical Interchange Format
htm, html	Страница на языке разметки HTML
ini	Файл конфигурации для инициализации Windows
iso	Образ диска ISO-9660
jar	Файл архитектуры Java
jpg, jpeg	Файл фотографии Joint Photographic Experts Group
m4a	Звуковой файл MPEG-4
mdb	База данных Microsoft Access до Access 2007
mid, midi	Файл интерфейса Musical Instrument Digital Interface
mov	Видеофайл Apple QuickTime
.mp3	Аудиофайл MPEG Layer-3
mp4	Видео MPEG 4
mp4	Видео MPEG 4
mpeg	Видеофайл Moving Picture Experts Group
mpg	Поток в формате MPEG 1
msi	Файл установщика Майкрософт
mui	Файл многоязычного пользовательского интерфейса
pdf	Файл Portable Document Format
png	Файл Portable Network Graphics
pot	Шаблон Microsoft PowerPoint до PowerPoint 2007
potm	Шаблон Microsoft PowerPoint с включенной поддержкой макросов
potx	Шаблон Microsoft PowerPoint
ppam	Надстройка Microsoft PowerPoint
pps	Слайд-шоу Microsoft PowerPoint до PowerPoint 2007
ppsm	Слайд-шоу Microsoft PowerPoint с включенной поддержкой макросов
ppsx	Слайд-шоу Microsoft PowerPoint
ppt	Формат Microsoft PowerPoint до PowerPoint 2007
pptm	Презентация Microsoft PowerPoint с включенной поддержкой макросов
pptx	Презентация Microsoft PowerPoint
psd	Файл Adobe Photoshop
pst	Хранилище данных Outlook
pub	Файл Microsoft Publisher
rar	Сжатый файл архива Roshal
rtf	Текстовый файл в формате Rich Text Format
sldm	Слайд Microsoft PowerPoint с включенной поддержкой макросов
sldx	Слайд Microsoft PowerPoint
swf	Файл Shockwave Flash
sys	Файл переменных и системных параметров Microsoft DOS и Windows
tif, tiff	Файл Tagged Image Format
tmp	Файл временных данных
txt	Файл неформатированного текста
vob	Файл видеообъекта
vsd	Рисунок Microsoft Visio до Visio 2013
vsdm	Рисунок Microsoft Visio с включенными макросами
vsdx	Файл рисунка Microsoft Visio
vss	Трафарет Microsoft Visio до Visio 2013
vssm	Трафарет Microsoft Visio с включенными макросами
vst	Шаблон Microsoft Visio до Visio 2013
vstm	Шаблон Microsoft Visio с включенными макросами
vstx	Шаблон Microsoft Visio
wav	Звуковой файл Wave
wbk	Архивный документ Microsoft Word
wks	Файл Microsoft Works
wma	Файл Windows Media Audio
wmd	Файл Windows Media Download
wmv	Файл Windows Media Video
wmz, wms	Файл обложек Windows Media
wpd, wp5	Документ WordPerfect
xla	Файл надстройки или макроса Microsoft Excel
xlam	Надстройка Microsoft Excel после Excel 2007
xll	Надстройка Microsoft Excel на основе DLL
xlm	Макрос Microsoft Excel до Excel 2007
xls	Рабочая книга Microsoft Excel до Excel 2007
xlsm	Рабочая книга Microsoft Excel с включенной поддержкой макросов после Excel 2007
xlsx	Рабочая книга Microsoft Excel после Excel 2007
xlt	Шаблон Microsoft Excel до Excel 2007
xltm	Шаблон Microsoft Excel с включенной поддержкой макросов после Excel 2007
xltx	Шаблон Microsoft Excel после Excel 2007
xps	Документ на основе XML
zip	Сжатый файл

Связанные ссылки

• Форматы Open XML и расширения имен файлов

• Форматы файлов, поддерживаемые проигрывателем Windows Media

• Форматы файлов, поддерживаемые в Excel

• Форматы файлов, поддерживаемые в PowerPoint

• Форматы файлов, поддерживаемые в Project

Обзор форматов файлов и сведения о них