List of audio formats .3gp Multimedia container format can contain proprietary formats as AMR, AMR-WB or AMR-WB+, but also some open formats .aa Audible.com (Amazon.com) Low-bitrate audiobook container format with DRM, containing audio encoded as either MP3 or the ACELP speech codec. .aac The Advanced Audio Coding format is based on the MPEG-2 and MPEG-4 standards. AAC files are usually ADTS or ADIF containers. .aax Audible.com (Amazon.com) Audiobook format, which is a variable-bitrate (allowing high quality) M4B file encrypted with DRM. MPB contains AAC or ALAC encoded audio in an MPEG-4 container. (More details below.) .act ACT is a lossy ADPCM 8 kbit/s compressed audio format recorded by most Chinese MP3 and MP4 players with a recording function, and voice recorders .aiff Apple Standard audio file format used by Apple. It could be considered the Apple equivalent of wav. .amr AMR-NB audio, used primarily for speech. .ape Matthew T. Ashland Monkey's Audio lossless audio compression format. .au Sun Microsystems The standard audio file format used by Sun, Unix and Java. The audio in au files can be PCM or compressed with the μ-law, a-law or G729 codecs. .awb AMR-WB audio, used primarily for speech, same as the ITU-T's G.722.2 specification. .dct NCH Software A variable codec format designed for dictation. It has dictation header information and can be encrypted (as may be required by medical confidentiality laws). A proprietary format of NCH Software. .dss Olympus DSS files are an Olympus proprietary format. It is a fairly old and poor codec. GSM or MP3 are generally preferred where the recorder allows. It allows additional data to be held in the file header. .dvf Sony A Sony proprietary format for compressed voice files; commonly used by Sony dictation recorders. .flac File format for the Free Lossless Audio Codec, a lossless compression codec. .gsm Designed for telephony use in Europe, gsm is a very practical format for telephone quality voice. It makes a good compromise between file size and quality. Note that wav files can also be encoded with the gsm codec. .iklax iKlax An iKlax Media proprietary format, the iKlax format is a multi-track digital audio format allowing various actions on musical data, for instance on mixing and volumes arrangements. .ivs 3D Solar UK Ltd A proprietary version with Digital Rights Management developed by 3D Solar UK Ltd for use in music downloaded from their Tronme Music Store and interactive music and video player. .m4a An audio-only MPEG-4 file, used by Apple for unprotected music downloaded from their iTunes Music Store. Audio within the m4a file is typically encoded with AAC, although lossless ALAC may also be used. .m4b Audiobook / podcast extension with AAC or ALAC encoded audio in an MPEG-4 container. Both M4A and M4B formats can contain metadata including chapter markers, images, and hyperlinks, but M4B allows "bookmarks" (remembering the last listening spot), whereas M4A does not. .m4p Apple A version of AAC with proprietary Digital Rights Management developed by Apple for use in music downloaded from their iTunes Music Store. .mmf Yamaha, Samsung a Samsung audio format that is used in ringtones. Developed by Yamaha (SMAF stands for "Synthetic music Mobile Application Format", and is a multimedia data format invented by the Yamaha Corporation, .mmf file format). .mp3 MPEG Layer III Audio. Is the most common sound file format used today. .mpc Musepack or MPC (formerly known as MPEGplus, MPEG+ or MP+) is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160–180 kbit/s. .msv Sony A Sony proprietary format for Memory Stick compressed voice files. .ogg, .oga, mogg Xiph.Org Foundation A free, open source container format supporting a variety of formats, the most popular of which is the audio format Vorbis. Vorbis offers compression similar to MP3 but is less popular. Mogg, the "Multi-Track-Single-Logical-Stream Ogg-Vorbis", is the multi-channel or multi-track Ogg file format. .opus Internet Engineering Task Force A lossy audio compression format developed by the Internet Engineering Task Force (IETF) and made especially suitable for interactive real-time applications over the Internet. As an open format standardised through RFC 6716, a reference implementation is provided under the 3-clause BSD license. .ra, .rm RealNetworks A RealAudio format designed for streaming audio over the Internet. The .ra format allows files to be stored in a self-contained fashion on a computer, with all of the audio data contained inside the file itself. .raw A raw file can contain audio in any format but is usually used with PCM audio data. It is rarely used except for technical tests. .sln Signed Linear PCM format used by Asterisk. Prior to v.10 the standard formats were 16-bit Signed Linear PCM sampled at 8 kHz and at 16 kHz. With v.10 many more sampling rates were added. .tta The True Audio, real-time lossless audio codec. .vox The vox format most commonly uses the Dialogic ADPCM (Adaptive Differential Pulse Code Modulation) codec. Similar to other ADPCM formats, it compresses to 4-bits. Vox format files are similar to wave files except that the vox files contain no information about the file itself so the codec sample rate and number of channels must first be specified in order to play a vox file. .wav Standard audio file container format used mainly in Windows PCs. Commonly used for storing uncompressed (PCM), CD-quality sound files, which means that they can be large in size—around 10 MB per minute. Wave files can also contain data encoded with a variety of (lossy) codecs to reduce the file size (for example the GSM or MP3 formats). Wav files use a RIFF structure. .wma Microsoft Windows Media Audio format, created by Microsoft. Designed with Digital Rights Management (DRM) abilities for copy protection. .wv Format for wavpack file http://www.wavpack.com/flash/wavpack.htm .webm Royalty-free format created for HTML5 video.