| .A2M | TallStick Software | Arquivos de áudio | TS-AudioToMIDI Settings File | TS-AudioToMIDI | TallStick Software |
| .A2P | Adlib Tracker II | Arquivos de áudio | Adlib Tracker II Pattern File | Adlib Tracker II | Adlib Tracker II |
| .A2W | Carnegie Mellon University | Arquivos de áudio | Alice World | Alice | Carnegie Mellon University |
| .A3K | Yamaha Corporation | Arquivos de áudio | Yamaha A3000 Sampler Data | Yamaha A3000 | Yamaha Corporation |
| .A52 | Atari Corporation | Arquivos de áudio | Atari 5200 ROM | MESS | Open Source |
| .AA | Audible | Arquivos de áudio | Audible Audio Book File | Apple iTunes | Apple |
| .AA3 | Sony | Arquivos de áudio | ATRAC Audio File | MAGIX Vegas | Magix Software GmbH |
| .AAC | Xilisoft Corporation | Arquivos de áudio | Advanced Audio Coding File | Apple iTunes | Apple |
| .AAX | Audible | Arquivos de áudio | Audible Enhanced Audiobook File | Apple iTunes | Apple |
| .ABC | Adobe Systems Incorporated | Arquivos de áudio | ActionScript Byte Code File | Adobe Flash Player | Adobe Systems Incorporated |
| .ABM | Unknown Developer | Arquivos de áudio | Music Album | Redbana Audition | Redbana |
| .AC3 | Various Developers | Arquivos de áudio | Audio Codec 3 File | CyberLink PowerDVD | CyberLink |
| .AC7 | National Instruments | Arquivos de áudio | SPICE AC/Frequency Domain Output File | Spice | National Instruments |
| .ACD | Sony Creative Software | Arquivos de áudio | ACID Project File | ACID XPress | Sony |
| .ACM | BioWare | Arquivos de áudio | Interplay Audio File | Nullsoft Winamp | Nullsoft |
| .ACP | Alfresco Software, Inc. | Arquivos de áudio | Alfresco Content Package | Alfresco | Alfresco Software, Inc. |
| .ACT | Bell Labs | Arquivos de áudio | ADPCM Compressed Audio File | Unknown Software | Unknown Developer |
| .AD2 | Unknown Developer | Arquivos de áudio | ADPCM 2-bit Compressed Voice | Awave Studio | FMJ-Software |
| .AD3 | Open Source | Arquivos de áudio | ADPCM 3-bit Compressed Voice | SoX | Open Source |
| .ADE | Microsoft Corporation | Arquivos de áudio | Access Project Extension | Microsoft Access | Microsoft Corporation |
| .ADPCM | Microsoft Corporation | Arquivos de áudio | ADPCM Audio | Microsoft Windows Media Player | Microsoft Corporation |
| .ADT | Swiftpage, Inc. | Arquivos de áudio | ACT! Document Template | Swiftpage Act | Swiftpage, Inc. |
| .ADTS | Shedworx | Arquivos de áudio | Audio Data Transport Stream File | Microsoft Windows Media Player | Microsoft Corporation |
| .ADV | Unknown Developer | Arquivos de áudio | Audio Driver File | Dune | Cryo Interactive Entertainment |
| .ADX | CRI Middleware | Arquivos de áudio | ADX Audio File | FFmpeg | FFmpeg team |
| .AFC | Electronic Arts | Arquivos de áudio | Mass Effect 2 Audio File | Mass Effect 2 | BioWare |
| .AGM | Digital Theater Systems (DTS) Inc. | Arquivos de áudio | DTS Multi-channel Pro Packer File | DTS Pro Series Surround Encoder | Digital Theater Systems (DTS) Inc. |
| .AGR | Ableton | Arquivos de áudio | Ableton Groove File | Ableton Live | Ableton |
| .AHX | Abyss | Arquivos de áudio | WinAHX Tracker Module | CocoModX | Open Source |
| .AIF | Apple | Arquivos de áudio | Audio Interchange File Format | Microsoft Windows Media Player | Microsoft Corporation |
| .AIFC | Apple | Arquivos de áudio | Compressed Audio Interchange File | Microsoft Windows Media Player | Microsoft Corporation |
| .AIFF | Apple | Arquivos de áudio | Audio Interchange File Format | Microsoft Windows Media Player | Microsoft Corporation |
| .AIS | Extreme | Arquivos de áudio | Velvet Studio Instrument | Velvet Studio | Extreme |
| .AIX | Unknown Developer | Arquivos de áudio | AIX Audio File | adXtract | Halley's Comet Software |
| .AJZ | Archos | Arquivos de áudio | Archos Jukebox Recorder Firmware Update | Archos' Jukebox Recorder | Archos |
| .AKP | Propellerhead | Arquivos de áudio | Akai Sampler File | ReCycle | Propellerhead |
| .AL | ITU-T (International Telecommunication Union, Telecommunication Standardization Sector) | Arquivos de áudio | A-Law Compressed Sound Format | Apple QuickTime Player | Apple |
| .ALAW | ITU-T (International Telecommunication Union, Telecommunication Standardization Sector) | Arquivos de áudio | A-Law Compressed Sound Format | Apple QuickTime Player | Apple |
| .ALC | Ableton | Arquivos de áudio | Ableton Live Clip File | Ableton Live | Ableton |
| .ALL | Steinberg | Arquivos de áudio | Cubase Project | Steinberg Cubase | Steinberg |
| .ALS | Ableton | Arquivos de áudio | Ableton Live Set File | Ableton Live | Ableton |
| .AMF | Autodesk, Inc. | Arquivos de áudio | Additive Manufacturing File | Autodesk Meshmixer | Autodesk, Inc. |
| .AML | Intel Corporation | Arquivos de áudio | ACPI Machine Language File | DSDTSE | otRock |
| .AMR | Open Source | Arquivos de áudio | Adaptive Multi-Rate Codec File | Apple QuickTime Player | Apple |
| .AMS | Adobe Systems Incorporated | Arquivos de áudio | Adobe Monitor Setup File | Adobe Photoshop CC | Adobe Systems Incorporated |
| .ANG | Anghami | Arquivos de áudio | Anghami Audio File | Anghami | Anghami |
| .AOB | Unknown Developer | Arquivos de áudio | DVD-Audio Audio Object File | CyberLink PowerDVD | CyberLink |
| .APE | Nullsoft | Arquivos de áudio | AVS Plugin Effects File | Nullsoft Winamp | Nullsoft |
| .APF | Adobe Systems Incorporated | Arquivos de áudio | Adobe Profile File | Adobe Acrobat DC | Adobe Systems Incorporated |
| .APL | Matthew T. Ashland | Arquivos de áudio | Monkey's Audio Track Information File | Microsoft Windows Media Player | Microsoft Corporation |
| .ARL | AOL | Arquivos de áudio | AOL Organizer File | AOL Organizer | AOL |
| .ARR | Lemkesoft | Arquivos de áudio | Amber Graphic File | Lemkesoft GraphicConverter | Lemkesoft |
| .ARS | Adobe Systems Incorporated | Arquivos de áudio | After Effects Render Settings File | Adobe After Effects | Adobe Systems Incorporated |
| .ASC | Symantec Corporation | Arquivos de áudio | PGP (Pretty Good Privacy) ASCII Armored File | Mozilla Thunderbird | Mozilla |
| .ASD | Microsoft Corporation | Arquivos de áudio | Word AutoSave File | Microsoft Word | Microsoft Corporation |
| .ASE | Adobe Systems Incorporated | Arquivos de áudio | Adobe Swatch Exchange File | Adobe Illustrator CC | Adobe Systems Incorporated |
| .AT3 | Sony | Arquivos de áudio | ATRAC3 Audio File | MAGIX Vegas | Magix Software GmbH |
| .AU | Open Source | Arquivos de áudio | Audacity Audio File | Audacity | Open Source |
| .AUD | Interscape | Arquivos de áudio | Video Game Compressed Audio File | Command and Conquer | Interscape |
| .AUF | Planit Solutions, Inc. | Arquivos de áudio | Alphacam User Font | Planit Alphacam | Planit Solutions, Inc. |
| .AUP | Open Source | Arquivos de áudio | Audacity Project Audio File | Audacity | Open Source |
| .AWB | Nokia | Arquivos de áudio | AMR-WB Audio File | Apple QuickTime Player | Apple |
| .AXA | CSIRO | Arquivos de áudio | Annodex Audio File | VLC Media Player | VideoLAN |
| .AY | Richard Bannister | Arquivos de áudio | AY Chiptune File | Audio Overload | Richard Bannister |
| .AZX | Unknown Developer | Arquivos de áudio | ZX Audio File Format | Unknown Software | Unknown Developer |
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