File formats: A

Every format whose extension starts with A.

Formats

FormatNameAboutMain software
.AStatic library archiveUnix static libraries: object files in an ar archive with a symbol index.GNU BinutilsDocumentedViewerEditorOpen
.AACAdvanced Audio CodingMP3’s successor: ADTS frames in .aac, or MPEG-4 boxes in .m4a.VLC media playerDocumentedViewerEditorOpen
.ABCAlembic geometry cacheBaked animated geometry for film pipelines: every point on every frame.Autodesk MayaDocumentedViewerEditorOpen
.AC3Dolby Digital audioDolby Digital surround sound: sync frames of six 256-sample audio blocks.VLC media playerDocumentedViewerEditorOpen
.ADFAmiga Disk FileAn Amiga floppy disk, every 512-byte sector in order.WinUAEDocumentedViewerEditorOpen
.ADOCAsciiDocPlain text markup for technical documents and books, built by Asciidoctor.AsciidoctorDocumentedViewerEditorOpen
.AEPAdobe After Effects projectAn After Effects project: compositions and layers in big-endian RIFX chunks.Adobe After EffectsDocumentedViewerEditorOpen
.AFPHOTOAffinity Photo documentAffinity Photo’s working file, with layers, adjustments and masks.Affinity PhotoDocumentedViewerEditorOpen
.AIAdobe Illustrator ArtworkIllustrator's working file: a PDF carrying Illustrator's own editing data.Adobe IllustratorDocumentedViewerEditorOpen
.AIFFAudio Interchange File FormatApple’s uncompressed audio, big-endian samples in IFF chunks.Logic ProDocumentedViewerEditorOpen
.ALSAbleton Live SetAn Ableton Live project: gzip-compressed XML of tracks, clips and devices.Ableton LiveDocumentedViewerEditorOpen
.AMFAdditive Manufacturing File FormatThe ASTM XML format meant to replace STL, with units, materials and colours.PrusaSlicerDocumentedViewerEditorOpen
.AMRAdaptive Multi-Rate speechMobile phone speech: a #!AMR line, then 20 ms frames.VLC media playerDocumentedViewerEditorOpen
.ANIWindows animated cursorAnimated Windows mouse pointers: cursor frames and timing in RIFF chunks.WindowsDocumentedViewerEditorOpen
.APEMonkey’s AudioHigh-ratio lossless compression from Monkey’s Audio, with APEv2 tags.foobar2000DocumentedViewerEditorOpen
.APKAndroid packageAndroid apps: a signed ZIP of DEX code, resources and a manifest.AndroidDocumentedViewerEditorOpen
.APPIMAGEAppImage applicationA Linux app in one runnable file: an ELF runtime and a SquashFS image.LinuxDocumentedViewerEditorOpen
.ARJARJ archiveA popular 1990s DOS archiver, with headers starting 60 EA.7-ZipDocumentedViewerEditorOpen
.ARROWApache Arrow IPC fileColumnar tables in Arrow’s in-memory layout, ready to memory-map.DuckDBDocumentedViewerEditorOpen
.ARWSony Alpha RawSony’s raw photo format, a little-endian TIFF with Sony’s own tags.Adobe LightroomDocumentedViewerEditorOpen
.ASCOpenPGP keyPGP and GnuPG keys: OpenPGP packets, as binary or base64 armour.GnuPGDocumentedViewerEditorOpen
.ASSAdvanced SubStation Alpha subtitlesStyled subtitles in INI-like sections: styles, then timed dialogue lines.AegisubDocumentedViewerEditorOpen
.ASXAdvanced Stream RedirectorA Windows Media metafile: XML-like entries pointing to streams and files.VLC media playerDocumentedViewerEditorOpen
.ATRAtari 8-bit disk imageAn Atari 400, 800, XL or XE floppy: a 16-byte header, then every sector.AltirraDocumentedViewerEditorOpen
.AUSun/NeXT audioUnix audio: a 24-byte big-endian header, then the samples, often µ-law.AudacityDocumentedViewerEditorOpen
.AUP3Audacity projectAn Audacity project: a SQLite database holding the edits and the audio.AudacityDocumentedViewerEditorOpen
.AVIAudio Video InterleaveMicrosoft’s RIFF video container from 1992, with interleaved chunks and an index.VLC media playerDocumentedViewerEditorOpen
.AVIFAV1 Image File FormatRoyalty-free AV1-compressed images in HEIF boxes, with alpha, HDR and animation.Google ChromeDocumentedViewerEditorOpen
.AVROApache Avro object container fileRecords in compact binary, with their JSON schema in the file header.Avro ToolsDocumentedViewerEditorOpen
.AZW3Kindle Format 8 ebookAmazon’s Kindle Format 8: HTML5 and CSS books in the MOBI record container.KindleDocumentedViewerEditorOpen