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The following tables compare general and technical information for a variety of audio formats and audio compression formats. For listening tests comparing the perceived audio quality of audio formats and codecs, see the article Codec listening test.

Contents

General information

General Information about Audio Compression Formats - creator/company, license/price etc.
Audio compression format Creator First public release date Latest stable version Encoder Cost Player Cost Proprietary implementations (codecs) Open-source implementations (codecs) Application Patented DRM
AAC ISO/IEC MPEG Audio Committee 1997 ISO/IEC 14496-3 Non-free [1] Non-free [2] FAAC (encoding only), iTunes, Nero Digital Audio FAAD2 (decoding only), FFmpeg, Android OpenCORE AAC (decoding only)[3] music Non-free Yes Non-free FairPlay (.m4p Only, Discontinued)
AC3 Dolby Laboratories 1992 ? Non-freevaries Non-freevaries DVD players, Digital television FFmpeg, liba52 (decoding only), Aften (encoding only), libavc (2.0 channels max) movies Non-free Yes ?
ALAC Apple Computer 2004-04-28 QuickTime 7.6 Free Free QuickTime, iTunes, Real Player FFmpeg Lossless compression ? No
ALS ISO/IEC MPEG Audio Committee 2005 ISO/IEC 14496-3 Free Free mp4als FFmpeg (decoding only) Lossless compression Non-free Yes ?
AMR 3GPP 1999-04-22 ETSI TS 126 071 V8.0.0 (2009-01) Non-freevaries[4][5] Non-freevaries[4][5] QuickTime, Real Player FFmpeg (decoding only), FFmpeg with OpenCORE libraries[6], Android[7] voice recording, telephony Non-free Yes No
AMR-WB
(G.722.2)
3GPP 2001-04-10 ETSI TS 126 190 V8.0.0 (2009-01) Non-freevaries Non-freevaries QuickTime, Real Player FFmpeg with OpenCORE libraries (decoding only)[6], Android (decoding only)[7] voice recording, telephony Non-free Yes No
AMR-WB+ 3GPP 2004-06-14 ETSI TS 126 290 V8.0.0 (2009-01) Non-freevaries[8][9] Non-freevaries[8][9]  ?  ? voice recording, music Non-free Yes No
apt-X APT 1989 2007 Non-freevaries Non-freevaries broadcast audio codecs: APT, AVT, Harris Corporation, MAYAH, Prodys, Qbit; wireless headphones: iSkin, JayBird Gear, DTS discs for movies ? low latency Studio/transmitter link, Bluetooth A2DP stereo, digital Wireless microphone Non-free Yes ?
ATRAC Sony Corp. 1991 ATRAC3plus Non-freevaries Non-freevaries MiniDisc, Walkman, VAIO, Clie, PlayStation3, PlayStation Portable, SDDS, SonicStage, SoundForge, RealPlayer, ConnectPlayer FFmpeg (decoding only, ATRAC3plus and ATRAC Advanced Lossless are not supported) voice recording, music, movies, Lossless Ripping mode for music Non-free Yes Non-free Yes
CELT Xiph.Org Foundation, Jean-Marc Valin 2007-12-08 0.6.1 Free Free CELT [10] Music, Speech, VoIP, Low latency, Studio/transmitter link, wireless audio No No
FLAC Xiph.Org Foundation, Josh Coalson 2001-07-20 1.2.1 Free Free FLAC[11], FFmpeg Lossless compression No No
G.711 ITU-T 1972 (ITU-T standard from 1988) G.711 Appendix II (02/00) Free Free various proprietary VoIP software FFmpeg, Ekiga, Asterisk (PBX) and almost any VoIP software voice recording, telephony No No
G.722 ITU-T 1988-11 Free Free various proprietary VoIP software Asterisk (PBX), QuteCom and other VoIP software voice recording, telephony No No
G.722.1 ITU-T 1999-09 G.722.1 (05/05) Free[12][13] Free[12][13] various proprietary VoIP software FreeSWITCH [14], pjsip, etc voice recording, telephony Non-free Yes No
G.722.2
(AMR-WB)
ITU-T (adopted directly from 3GPP) 2002-01 G.722.2 (07/03) Non-freevaries Non-freevaries QuickTime, Real Player FFmpeg with OpenCORE libraries (decoding only) [6], Android (decoding only)[7] voice recording, audio Non-free Yes No
G.723.1 ITU-T 1996-03 G.723.1 (05/06) Non-freevaries Non-freevaries various proprietary VoIP software ? voice recording, telephony Non-free Yes No
G.726 ITU-T 1990-12 Free Free various proprietary VoIP software FFmpeg, Ekiga and other VoIP software voice recording, telephony No No
G.728 ITU-T 1992-09 Non-freevaries Non-freevaries various proprietary VoIP software voice recording, telephony Non-free Yes No
G.729 ITU-T 1996-03 G.729 (01/07) Non-freevaries Non-freevaries various proprietary VoIP software FFmpeg (decoding only) voice recording, telephony Non-free Yes No
GSM-FR ETSI Special Mobile Group 1990-1994 (ETS 300 580-2) ETSI EN 300 961 V8.1.1 (2000-11) Free Free FFmpeg with external library libgsm, Ekiga and other VoIP software voice recording, telephony  ? No
iLBC Global IP Solutions 2002 Free Free Cisco IP Communicator[15], old versions of Skype[16] Ekiga, Asterisk (PBX) and other VoIP software voice recording, telephony  ? No
Monkey's Audio Matthew T. Ashland 2000+ 4.06 Free Free Monkey's Audio FFmpeg (decoding only) Lossless compression ? No
MP3 ISO/IEC MPEG Audio Committee 1993 ISO/IEC 11172-3, ISO/IEC 13818-3 Non-free (See notes) Non-free (See notes) FhG, l3enc, MP3enc, (old implementations: Xing TOMPG, SCMPX) LAME (encoding only), FFmpeg (decoding only), (old implementations: BladeEnc) music Non-free Yes
(but see notes)
Non-free Yes (optional, rarely used)
MP2 (MPEG-1, 2 Audio Layer II) ISO/IEC MPEG Audio Committee 1993 ISO/IEC 11172-3, ISO/IEC 13818-3 Non-freevaries Non-freevaries various DVD software, video software, audio software TooLAME (encoding only), TwoLAME (encoding only), FFmpeg (integer-only) music Non-free Yes[17]  ?
Musepack Frank Klemm/MDT 1997 1.30 (2009-04-02) Free Free Musepack[18], FFmpeg (decoding only) music Maybe [19] ?
Nellymoser Asao Nellymoser Inc. 2002  ? Non-freevaries Non-freevaries Adobe Flash, Flash Player FFmpeg voice recording Non-free Yes  ?
Shorten Tony Robinson 1. Free Free Shorten, FFmpeg (decoding only) Lossless compression No No
SILK Skype Limited 2009-01-07 Free Free Skype voice recording, telephony Non-free Yes ?
Siren 7 PictureTel Corp. (now Polycom Inc.) 1999 ?[12][13] ?[12][13] Microsoft Office Communicator FreeSWITCH (libg722_1[20], aMSN (libsiren - part of libmsn)[21][22] voice recording, telephony Non-free Yes ?
Speex Xiph.Org Foundation, Jean-Marc Valin 2003-03-24 1.1.12 Free Free Flash Player 10 Speex[23], FFmpeg with libspeex libraries voice recording, telephony No No
SVOPC Skype Limited 2007 ? ? Skype voice recording, telephony Non-free Yes ?
TwinVQ Nippon Telegraph and Telephone 1996 (?) Non-freevaries Non-freevaries Winamp with VQF Plugin, NTT TwinVQ player/encoder, Yamaha SoundVQ player, Nero Media Player FFmpeg (decoding only)[24] music, speech Non-free Yes ?
Vorbis (Ogg) Xiph.Org Foundation 2000-05-11 1.2 Free Free libvorbis[25], aoTuV[26], FFmpeg music No No
WavPack Conifer Software 1998 4.60.1 Free Free WavPack[27], FFmpeg (decoding only) Lossless compression, lossy and hybrid compression No No
Windows Media Audio Microsoft Corp. 1999 11.0 Free Windows Media Encoder[28] Free for licensees of the Windows operating system [2] Windows Media Player, Windows Media Encoder FFmpeg (decoding only for Pro and Voice, Lossless is not supported) music Non-free Yes Non-free [29]
Audio compression format Creator First public release date Latest stable version Encoder Cost Player Cost Proprietary implementations (codecs) Open-source implementations (codecs) Application Patented DRM
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Notes

  1. First public release date is first of either specification publishing or source releasing, or in the case of closed-specification, closed-source codecs, is the date of first binary releasing. Many developing codecs have pre-releases consisting of pre-1.0 versions and perhaps 1.0 release candidates (RCs), although 1.0 may not necessarily be the release version.
  2. Latest stable version is that of specification or reference tools.
  3. If there happens to be OSI licensed software available for a particular codec, this does not necessarily permit one to use said codec free of charge. Likewise, if there is only proprietary licensed software available for a particular codec, one might be able to use the codec free of charge.
  4. MP3 licence and patent status: The MP3 format is patented and therefore subject to license (expires latest: 2017). However with multiple contenders for the patent, it is far from certain in the market who is the patent holder with the right to set pricing and royalties. A sample of prices for one patent-holder is available. In practice, there is a wide range of MP3 authoring software and MP3 encoding worldwide is often performed on a private basis and unpaid, with patent rights unenforced against end users. See MP3#Licensing and patent issues.

Operating System Support

Audio Codec OS Support
Codec Windows Mac OS X Linux BSD Unix Palm OS
AAC Yes Yes Yes Yes Yes Yes
ALAC[30] Yes Yes Yes Yes Yes No
apt-X Yes Yes Yes Yes Yes No
CELT Yes Yes Yes Yes Yes Yes
FLAC Yes Yes Yes Yes Yes Yes
Monkey's Audio Yes Yes Yes Yes Yes No
MP3 Yes Yes Yes Yes Yes Yes
Musepack Yes Yes Yes Yes Yes Yes
RealAudio[31] Yes Yes Yes Yes Yes Yes
Speex Yes Yes Yes Yes Yes Yes
Vorbis Yes Yes Yes Yes Yes Yes
WavPack Yes Yes Yes Yes Yes Yes
WMA[31] Yes Yes[32] Partial Partial Partial Yes

Multimedia Frameworks Support

Multimedia Frameworks Support for Audio Compression Formats
Audio compression format ACM DirectShow QuickTime GStreamer FFmpeg
8SVX Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
AAC Yes (ffdshow) Yes (ffdshow, Monogram[33]) Yes Yes (GStreamer FFmpeg plug-in) Yes
HE-AAC Yes (ffdshow) Yes (ffdshow, Monogram[33]) Yes No Yes
AC3 Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
E-AC-3 Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
AMR No No No Yes (GStreamer Ugly Plug-ins) Yes
Apple Lossless Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Cook Codec Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
ATRAC3 Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
ATRAC3plus No No No No No
DCA aka DTS Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
DTS-HD No No No No No
FLAC Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer Base Plug-ins, GStreamer FFmpeg plug-in) Yes
Monkey's Audio Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
WavPack Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Shorten Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Sonic Audio Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
MP3 Yes (ffdshow) Yes Yes Yes (GStreamer Ugly, GStreamer FFmpeg plug-in) Yes
RealAudio Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in, GStreamer DLL loader plugin + Binary Codec Packages) Yes
Speex Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Vorbis (Ogg) Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer Base Plug-ins, GStreamer FFmpeg plug-in) Yes
La No No No No No
LPAC No No No No No
Windows Media Audio v1 Yes (ffdshow) Yes Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Windows Media Audio v2 Yes (ffdshow) Yes Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Windows Media Audio Pro Yes (ffdshow) Yes Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Windows Media Audio Lossless No Yes Yes (flip4mac) No No
Windows Media Audio Voice No Yes No No Yes
Musepack Yes (ffdshow) Yes (ffdshow, Monogram[33]) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Meridian Lossless Packing Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Nellymoser Asao Codec in Flash Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
OptimFROG No No No No No
Truespeech Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
TTA Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
QCELP Yes (ffdshow) Yes (ffdshow) Yes Yes (GStreamer FFmpeg plug-in) Yes
Audio compression format ACM DirectShow QuickTime GStreamer FFmpeg

Technical details

Technical Details of Audio Compression Formats
Audio compression format Algorithm Sample Rate Bit rate[34] Bits per sample Latency CBR VBR Stereo Multichannel
AAC MDCT, Lossy, Hybrid 8 kHz to 192 kHz[35] 8 to 529 kbit/s (stereo) Any (typically uses fp internally) >100ms Yes Yes Yes: Dual, Mid/Side, Intensity, Parametric Yes: Up to 48 channels
AC3 Lossy 32, 44.1, 48 kHz 32 to 640 kbit/s ? 40.6ms Yes No Yes Yes: Up to 6 channels
ALAC Lossless 44.1 kHz to 192 kHz variable 16, 24[36] ? No Yes Yes Yes
AMR ACELP, Lossy 8 kHz 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.20, 12.20 kbit/s 13 25ms Yes Yes No No
AMR-WB
(G.722.2)
ACELP, Lossy 16 kHz 6.60-23.85 kbit/s
(6.60, 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbit/s)
14 25ms Yes Yes Yes: only in MPEG-4 Part 12 container No
AMR-WB+ ACELP, Lossy 8, 11.025, 16, 22.05, 32, 44.1, 48 kHz 6 kbit/s to 36 kbit/s (mono) 7 kbit/s to 48 kbit/s (stereo) 16 60–90 ms Yes Yes Yes No
apt-X Lossy 24 kHz to 48 kHz (stereo) 192 kbit/s to 384 kbit/s (stereo) 16, 24 2ms Yes (4:1) No Yes Yes: Up to 8 channels
CELT Lossy 32 to 96 kHz 2 kbit/sec to >1 mbit/sec 16 (Fixed-point); Any (using FP) 2ms - 14.5ms (8.9ms typical) Yes Yes Yes Yes
FLAC Lossless 1 Hz to 640 kHz variable 4, 8, 16, 24, (32) 4.3ms - 92ms (46.4ms typical) No Yes Yes Yes: Up to 8 channels
GSM-HR Lossy 8 kHz 5.6 kbit/s 13 25ms Yes No No No
GSM-FR Lossy 8 kHz 13 kbit/s 13 20-30ms Yes No No No
GSM-EFR ACELP, Lossy 8 kHz 12.2 kbit/s 13 20-30ms Yes No No No
HVXC Lossy 8 kHz 2 or 4 kbit/s 36ms Yes Yes No No
iLBC Lossy 8 kHz 13.33, 15.20 kbit/s 16 30, 20ms Yes No No No
Monkey's Audio Lossless 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48 kHz variable ? ? No Yes Yes No
MP3 (MPEG-1, 2, 2.5 Audio Layer III) MDCT, Lossy 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48 kHz 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 192, 224, 256, 320 kbit/s Any (typically uses fp internally) >100ms Yes Yes Yes: Dual, Mid/Side, Intensity No
MPEG-1 Audio Layer II (MP2) Lossy 32, 44.1, 48 kHz 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384 kbit/s varies Yes Yes: but decoders are not required to support it Yes No
MPEG-2 Audio Layer II (MP2) Lossy 16, 22.05, 24 kHz[37][38] 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 kbit/s[37] varies Yes Yes: but decoders are not required to support it Yes Yes: up to 5 full range audio channels and an LFE-channel with MPEG Multichannel
Musepack Lossy 32, 37.8, 44.1, 48 kHz 3 to 1300 kbit/s 8 to 32 ? No Yes Yes Yes: up to 8 channels
RealAudio Lossless, Lossy Varies (see article) Varies (see article) Varies (see article) Varies Yes Yes Yes Yes: Up to 6 channels
SILK Lossy 8, 12, 16, 24 kHz 6 to 40 kbit/s ? 25ms Yes ? ? ?
Siren 7 Lossy, derived from PT716plus 16 kHz 16, 24, 32 kbit/s ? 40ms Yes No No No
Siren 14 Lossy 32 kHz 24, 32, 48 kbit/s (mono), 48, 64, 96 kbit/s (stereo) ? 40ms Yes No Yes No
Siren 22 Lossy 48 kHz 32, 48, 64 kbit/s (mono), 64, 96, 128 kbit/s (stereo) ? 40ms Yes No Yes No
Speex Lossy, Speech 8, 16, 32 (, 48) kHz 2.15 to 24.6 kbit/s (NB); 4 to 44.2 kbit/s (WB) 16 30ms (NB) 34ms (WB) Yes Yes Yes: Intensity Yes
Vorbis (Ogg) MDCT, Lossy 1 Hz to 200 kHz variable Any (typically uses fp internally) >100ms Yes/ABR Yes Yes: Dual, Lossless, Phase, Point (Intensity) Yes: Up to 255 channels
WavPack Lossless, Lossy, Hybrid 1 Hz to 16.777216 MHz variable in lossless mode; 196 kbit/s and up in lossy mode (for CD audio) varies in lossless mode; 2.2 minimum in lossy mode ? Yes Yes Yes Yes: Up to 16 channels
Windows Media Audio Lossless, Lossy 8, 11.025, 16, 22.05, 32, 44.1, 48, 88.2, 96 kHz 4 to 768kbit/s, variable in lossless encoding 16, 24 for lossless mode, any in lossy mode (typically uses fp internally) >100ms Yes Yes Yes Yes: Up to 8 channels (WMA Professional), Up to 6 channels (WMA Lossless)
Technical Details of ITU-T Audio Compression Formats
Audio compression format Algorithm Sample Rate Bit rate[34] Bits per sample Latency CBR VBR Stereo Multichannel
G.711 companding A-law or μ-law, PCM, Lossy 8 kHz 64 kbit/s 13 bit 125µs (typical) Yes No No No
G.711.1 MDCT, A-law, u-law, Lossy 8 or 16 kHz 64, 80, 96 kbit/s 16 bit 11.875 ms Yes Yes No No
G.718 CELP, MDCT, Lossy 8 or 16 kHz 8, 12, 12.65, 16, 24, 32 kbit/s 16 bit 42.875 ms - 43.875 ms Yes Yes No No
G.719 Lossy, (incorporates elements of Siren Codec and Ericsson technology) 48 kHz 32-128 kbit/s
(Rates between 32 and 88 kbit/s shall be a multiple of 4 kbit/s; 88-128 kbit/s - a multiple of 8 kbit/s.)
16 bit 40 ms Yes No Yes: only in MPEG-4 Part 12 container Yes: only in MPEG-4 Part 12 container
G.721 ADPCM, Lossy 8 kHz 32 kbit/s 13 bit Yes No No No
G.722 sub-band ADPCM, Lossy 16 kHz 64 kbit/s
(comprises 48, 56 or 64 kbit/s audio and 16, 8 or 0 kbit/s auxiliary data)
14 bit 4 ms Yes No No No
G.722.1 Modulated Lapped Transform, (based on Siren Codec), Lossy 16 kHz 24, 32 kbit/s 16 bit 40 ms Yes No No No
G.722.1C Modulated Lapped Transform, (based on Siren Codec), Lossy 32 kHz 24, 32, 48 kbit/s 16 bit 40 ms Yes No No No
G.722.2 (AMR-WB) multi-rate wideband ACELP, Lossy 16 kHz 6.60-23.85 kbit/s
(6.60, 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbit/s)
14 bit 25 ms Yes Yes Yes: only in MPEG-4 Part 12 container No
G.723 ADPCM, Lossy 8 kHz 24 or 40 kbit/s 13 bit Yes No No No
G.723.1 MP-MLQ, ACELP, Lossy 8 kHz 5.3, 6.3 kbit/s 13 bit 37.5 ms Yes No No No
G.726 ADPCM, Lossy 8 kHz 16, 24, 32, 40 kbit/s 13 bit Yes No No No
G.727 ADPCM, Lossy 8 kHz 16, 24, 32, 40 kbit/s 13 bit Yes Yes No No
G.728 low-delay CELP, Lossy 8 kHz 16 kbit/s 13 bit 0.625 ms Yes No No No
G.729 CS-ACELP, Lossy 8 kHz 8 kbit/s 13 bit 15 ms Yes No No No
G.729D CS-ACELP, Lossy 8 kHz 6.4 kbit/s 13 bit Yes No No No
G.729E CS-ACELP, Lossy 8 kHz 11.8 kbit/s 13 bit 15 ms Yes No No No
G.729.1 CELP, TDBWE, TDAC, Lossy 8 or 16 kHz 8-32 kbit/s
(12 layers; 2 kbit/s steps, (10kbps omitted))
16 bit 48.9375 ms Yes Yes No No

Notes

  • The latency listed here is the total delay (frame size, plus all lookahead) at the normal operating sample rate (typically 44.1kHz).

See also

Notes & references

  1. ^ varies
  2. ^ varies
  3. ^ OpenCORE Media Framework, Retrieved 2009-08-13
  4. ^ a b VoiceAge Corporation (2007-10-14). "AMR Licensing Terms". Archive.org. http://web.archive.org/web/20071014162046/www.voiceage.com/amr_licterms.php. Retrieved 2009-09-12. 
  5. ^ a b VoiceAge Corporation (2007-06). "AMR Licensing Terms". VoiceAge Corporation. http://www.voiceage.com/amr_licterms.php. Retrieved 2009-09-12. 
  6. ^ a b c FFmpeg General Documentation - AMR external library, Retrieved on 2009-07-08
  7. ^ a b c Android AMR codecs, Retrieved on 2009-07-08
  8. ^ a b VoiceAge Corporation (2007-10-14). "AMR-WB+ Licensing Terms". Archive.org. http://web.archive.org/web/20071014161444/www.voiceage.com/amrwbplus_licterms.php. Retrieved 2009-09-12. 
  9. ^ a b VoiceAge Corporation (2006-11). "AMR-WB+ Licensing Terms". VoiceAge Corporation. http://www.voiceage.com/amrwbplus_licterms.php. Retrieved 2009-09-12. 
  10. ^ CELT codec - downloads, Retrieved 2009-09-01
  11. ^ FLAC website, Retrieved 2009-09-01
  12. ^ a b c d Polycom, Inc.. "Siren7/Siren14/G.719 License info". Polycom, Inc.. http://www.polycom.com/company/about_us/technology/siren_g7221/license_schedule.html. Retrieved 2009-09-07. 
  13. ^ a b c d Polycom, Inc.. "Polycom Siren 14/G 722.1C FAQs - What are the terms on the free license?". Polycom, Inc.. http://www.polycom.com/company/about_us/technology/siren14_g7221c/faq.html#license_q3. Retrieved 2009-09-07. 
  14. ^ libg722_1
  15. ^ Cisco IP Communicator 7.0 Data sheet - support for iLBC Retrieved on 2009-07-08
  16. ^ Skype Community, Current Codec Uses, Retrieved on 2009-07-08
  17. ^ Kuro5hin.org (2008-07-20) Patent Status of MPEG-1,H.261 and MPEG-2, Retrieved 2009-09-05
  18. ^ Musepack website, Retrieved 2009-09-01
  19. ^ [1]
  20. ^ freeswitch.org libg722_1 - README, Retrieved 2009-09-08
  21. ^ "Libmsn - is a reusable, open-source, fully documented library for connecting to Microsoft's MSN Messenger service.". Libmsn project at Sourceforge.net. 2009. http://sourceforge.net/projects/libmsn/. Retrieved 2009-09-07. 
  22. ^ KaKaRoTo (2008-02-12) MSN Protocol documentation, Pidgin.im mailinglist, Retrieved 2009-09-08
  23. ^ Speex website, Retrieved 2009-09-01
  24. ^ FFmpeg (2009-08-24) News - August 24, 2009 - TwinVQ decoding in upcoming stable version, Retrieved 2009-10-07
  25. ^ Vorbis website, Retrieved 2009-09-01
  26. ^ aoTuV website, Retrieved 2009-09-01
  27. ^ WavPack website, Retrieved 2009-09-01
  28. ^ Windows Media Encoder
  29. ^ Optional
  30. ^ An open-source decoder for ALAC has been reverse engineered.
  31. ^ a b The ffmpeg project has reverse engineered some codecs of the RealAudio and Windows Media Audio (DivX Audio v1 and DivX Audio v2) formats. This enables their use on any POSIX compatible system.
  32. ^ Microsoft has outsourced their WMA support on Mac OS X to Telestream, Inc. who created and maintain Windows Media Components for QuickTime, replacing Windows Media Player for Mac OS.
  33. ^ a b c Monogram DS filters, Retrieved 2009-10-22
  34. ^ a b Lossless compression is always VBR
  35. ^ MPEG 2 AAC was limited to a 96 kHz sampling rate, however, with MPEG 4 AAC, a later version part of the MPEG 4 specification, the maximum sampling rate has been increased to 192 kHz.
  36. ^ Apple Lossless Information
  37. ^ a b Predrag Supurovic (1998-09). "MPEG Audio Frame Header". http://www.mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm. Retrieved 2009-07-11. 
  38. ^ ISO/IEC JTC1/SC29/WG11 - Audio Subgroup. "MPEG Audio FAQ Version 9, MPEG-1 and MPEG-2 BC". http://mpeg.chiariglione.org/faq/mp1-aud/mp1-aud.htm. Retrieved 2010-02-27. 

External links


Template:Linkfarm The following tables compare general and technical information for a variety of audio compression formats and audio codecs. For listening tests comparing the perceived audio quality of audio codecs, see the article Codec listening test.

Contents

General information

General Information about Audio Compression Formats - creator/company, license/price etc.
Audio compression format Creator First public release date Latest stable version Encoder Cost Player Cost Proprietary implementations Open-source implementations Application Patented DRM
AAC ISO/IEC MPEG Audio Committee 1997 ISO/IEC 14496-3 varies varies iTunes, Nero Digital Audio FAAC, FAAD2, FFmpeg music Yes FairPlay (.m4p Only, Discontinued)
AC3 Dolby Laboratories 1992  ? varies varies DVD players, Digital television FFmpeg, Aften (write only), libavc (2.0 channels max) movies Yes  ?
ALAC Apple Computer 2004-04-28 QuickTime 7.6 Free Free QuickTime, iTunes, Real Player FFmpeg Lossless compression  ? No
AMR 3GPP 1999-04-22 ETSI TS 126 071 V8.0.0 (2009-01) varies varies QuickTime, Real Player FFmpeg with OpenCORE libraries [1], Android [2] voice recording, telephony Yes No
AMR-WB
(G.722.2)
3GPP 2001-04-10 ETSI TS 126 190 V8.0.0 (2009-01) varies varies QuickTime, Real Player FFmpeg with OpenCORE libraries (decoding only)[1], Android (decoding only)[2] voice recording, telephony Yes No
AMR-WB+ 3GPP 2004-06-14 ETSI TS 126 290 V8.0.0 (2009-01) varies varies  ?  ? voice recording, music Yes No
apt-X APT 1989 2007 varies varies broadcast audio codecs: APT, AVT, Harris Corporation, MAYAH, Prodys, Qbit; wireless headphones: iSkin, JayBird Gear, DTS discs for movies  ? low latency Studio/transmitter link, Bluetooth A2DP stereo, digital Wireless microphone Yes  ?
ATRAC Sony Corp. 1991 ATRAC3plus varies varies MiniDisc, Walkman, VAIO, Clie, PlayStation3, PlayStation Portable, SDDS, SonicStage, SoundForge, RealPlayer, ConnectPlayer FFmpeg(readonly) voice recording, music, movies, Lossless Ripping mode for music Yes Yes
CELT Xiph.Org Foundation 2007-12-08 0.5.2 Free Free reference Music, Speech, VoIP, Low latency, Studio/transmitter link, wireless audio No No
FLAC Xiph.Org Foundation 2001-07-20 1.2.1 Free Free reference, FFmpeg Lossless compression No No
G.711 ITU-T 1972 (ITU-T standard from 1988) G.711 Appendix II (02/00) Free Free various proprietary VoIP software FFmpeg, Ekiga, Asterisk (PBX) and almost any VoIP software voice recording, telephony No No
G.722 ITU-T 11/1988 Free Free various proprietary VoIP software Asterisk (PBX), QuteCom and other VoIP software voice recording, telephony No No
G.722.1 ITU-T 09/1999 G.722.1 (05/05)  ?  ? various proprietary VoIP software  ? voice recording, telephony Yes No
G.722.2
(AMR-WB)
ITU-T 01/2002 G.722.2 (07/03) varies varies QuickTime, Real Player FFmpeg with OpenCORE libraries (decoding only) [1], Android (decoding only)[2] voice recording, audio Yes No
G.723.1 ITU-T 03/1996 G.723.1 (05/06) varies varies various proprietary VoIP software  ? voice recording, telephony Yes No
G.726 ITU-T 12/1990 Free Free various proprietary VoIP software FFmpeg, Ekiga and other VoIP software voice recording, telephony No No
G.728 ITU-T 09/1992 varies varies various proprietary VoIP software voice recording, telephony Yes No
G.729 ITU-T 03/1996 G.729 (01/07) varies varies various proprietary VoIP software FFmpeg (readonly) voice recording, telephony Yes No
GSM-FR ETSI Special Mobile Group 1990-1994 (ETS 300 580-2) ETSI EN 300 961 V8.1.1 (2000-11) Free Free FFmpeg with external library libgsm, Ekiga and other VoIP software voice recording, telephony  ? No
iLBC Global IP Solutions 2002 Free Free Cisco IP Communicator[3], old versions of Skype[4] Ekiga, Asterisk (PBX) and other VoIP software voice recording, telephony  ? No
Monkey's Audio Matthew T. Ashland 2000+ 4.06 Free Free Monkey's Audio FFmpeg (readonly) Lossless compression  ? No
MP3 ISO/IEC MPEG Audio Committee 1993 ISO/IEC 11172-3, ISO/IEC 13818-3 (See notes) (See notes) FhG LAME, FFmpeg(readonly) music Yes
(but see notes)
Yes (optional, rarely used)
MP2 (MPEG-1, 2 Audio Layer II) ISO/IEC MPEG Audio Committee 1993 ISO/IEC 11172-3, ISO/IEC 13818-3 varies varies various DVD software, video software, audio software TooLAME, TwoLAME, FFmpeg(integer-only version) music Yes  ?
Musepack Frank Klemm/MDT 1997 1.16 Free Free reference, FFmpeg(readonly) music Maybe [1]  ?
Shorten Tony Robinson 1. Free Free Shorten, FFmpeg(readonly) Lossless compression No No
Speex Xiph.Org Foundation 2003-03-24 1.1.12 Free Free reference, FFmpeg with libspeex libraries voice recording, telephony No No
TAK Thomas Becker 2006-04-03 1.1.1 Free Free Reference Implementation Lossless compression No No
Vorbis (Ogg) Xiph.Org Foundation 2002-07-20 1.2 Free Free reference, aoTuV, FFmpeg music No No
WavPack Conifer Software 1998 4.50 Free Free reference, FFmpeg(readonly) Lossless compression No No
Windows Media Audio Microsoft Corp. 1999 11.0 Free [5] Free for licensees of the Windows operating system [2] Windows Media Player FFmpeg (WMA pro and lossless is not supported) music Yes Optional
Audio compression format Creator First public release date Latest stable version Encoder Cost Player Cost Proprietary implementations Open-source implementations Application Patented DRM

Notes

  1. First public release date is first of either specification publishing or source releasing, or in the case of closed-specification, closed-source codecs, is the date of first binary releasing. Many developing codecs have pre-releases consisting of pre-1.0 versions and perhaps 1.0 release candidates (RCs), although 1.0 may not necessarily be the release version.
  2. Latest stable version is that of specification or reference tools.
  3. If there happens to be OSI licensed software available for a particular codec, this does not necessarily permit one to use said codec free of charge. Likewise, if there is only proprietary licensed software available for a particular codec, one might be able to use the codec free of charge.
  4. MP3 licence and patent status: The MP3 format is patented and therefore subject to license (expires latest: 2017 but US patents after Dec 2012 may be invalid). However with multiple contenders for the patent, it is far from certain in the market who is the patent holder with the right to set pricing and royalties. A sample of prices for one patent-holder is available. In practice, there is a wide range of MP3 authoring software and MP3 encoding worldwide is often performed on a private basis and unpaid, with patent rights unenforced against end users. See MP3#Licensing and patent issues.

Operating System Support

Audio Codec OS Support
Codec Windows Mac OS X Linux BSD Unix Palm OS
AAC Yes Yes Yes Yes Yes Yes
ALAC[6] Yes Yes Yes Yes Yes No
apt-X Yes Yes Yes Yes Yes No
CELT Yes Yes Yes Yes Yes Yes
FLAC Yes Yes Yes Yes Yes Yes
Monkey's Audio Yes Yes Yes Yes Yes No
MP3 Yes Yes Yes Yes Yes Yes
Musepack Yes Yes Yes Yes Yes Yes
RealAudio[7] Yes Yes Yes Yes Yes Yes
Speex Yes Yes Yes Yes Yes Yes
TAK Yes No No No No No
Vorbis Yes Yes Yes Yes Yes Yes
WavPack Yes Yes Yes Yes Yes Yes
WMA[7] Yes Yes[8] Partial Partial Partial Yes

Multimedia Frameworks Support

Multimedia Frameworks Support for Audio Compression Formats
Audio compression format VFW DirectShow QuickTime GStreamer FFmpeg
8SVX Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
AAC Yes (ffdshow) Yes (ffdshow) Yes Yes (GStreamer FFmpeg plug-in) Yes
HE-AAC Yes (ffdshow) Yes (ffdshow) Partial No No
AC3 Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
E-AC-3 Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
AMR No No No No No
Apple Lossless Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Cook Codec Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
ATRAC1 No No No No No
ATRAC3 Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
ATRAC3plus No No No No No
ATRAC Advanced Lossless No No No No No
DCA aka DTS Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
DTS-HD No No No No No
FLAC Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer Base Plug-ins, GStreamer FFmpeg plug-in) Yes
Monkey's Audio Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
WavPack Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Shorten Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Sonic Audio Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
MP3 Yes (ffdshow) Yes Yes Yes (GStreamer Ugly, GStreamer FFmpeg plug-in) Yes
RealAudio Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in, GStreamer DLL loader plugin + Binary Codec Packages) Yes
Speex Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Vorbis (Ogg) Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer Base Plug-ins, GStreamer FFmpeg plug-in) Yes
Intel Music Coder Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Indeo Audio No No No No No
La No No No No No
LPAC No No No No No
Windows Media Audio v1 Yes (ffdshow) Yes Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Windows Media Audio v2 Yes (ffdshow) Yes Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Windows Media Audio Pro No Yes No No No
Windows Media Audio Lossless No Yes No No No
Windows Media Audio Voice No Yes No No No
Musepack Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Meridian Lossless Packing Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
Nellymoser Asao Codec in Flash Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
On2 Audio No No No No No
OptimFROG No No No No No
QDM2 Yes (ffdshow) Yes (ffdshow) Yes Yes (GStreamer FFmpeg plug-in) Yes
RK Audio No No No No No
TAK No No No No No
Truespeech Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
TTA Yes (ffdshow) Yes (ffdshow) Yes (Perian) Yes (GStreamer FFmpeg plug-in) Yes
QCELP Yes (ffdshow) Yes (ffdshow) Yes Yes (GStreamer FFmpeg plug-in) Yes
Siren No No No No No
ACELP.net No No No No No
Real Lossless Codec No No No No No
RealAudio sipr No No No No No
Audio compression format VFW DirectShow QuickTime GStreamer FFmpeg

Technical details

Technical Details of Audio Compression Formats
Audio compression format Algorithm Sample Rate Bit rate[9] Bits per sample Latency CBR VBR Stereo Multichannel
AAC Lossy, Hybrid 8 kHz to 192 kHz[10] 8 to 529 kbit/s (stereo) Any (typically uses fp internally) >100ms Yes Yes Yes: Dual, Mid/Side, Intensity, Parametric Yes: Up to 48 channels
AC3 Lossy 32, 44.1, 48 kHz 32 to 640 kbit/s  ? 40.6ms Yes No Yes Yes: Up to 6 channels
ALAC Lossless 44.1 kHz to 192 kHz variable 16, 24[11]  ? No Yes Yes Yes
AMR Lossy 8 kHz 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.20, 12.20 kbit/s 13 25ms Yes No No No
AMR-WB
(G.722.2)
Lossy 16 kHz 6.60-23.85 kbit/s
(6.60, 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbit/s)
14 25ms Yes No Yes: only in MPEG-4 Part 12 container No
AMR-WB+ Lossy 16, 24 kHz
(32, 48 kHz)
6.60-24 kbit/s
(6.60, 8.85, 12.65, 13.6, 14.25, 15.85, 18, 18.25, 19.85, 23.05, 23.85, 24 kbit/s)
16 25ms Yes No Yes No
apt-X Lossy 24 kHz to 48 kHz (stereo) 192 kbit/s to 384 kbit/s (stereo) 16, 24 2ms Yes (4:1) No Yes Yes: Up to 8 channels
CELT Lossy 32 - 96 kHz 2 kbit/sec to >1 mbit/sec 16 (Fixed-point); Any (using FP) 2ms - 14.5ms (8.9ms typical) Yes Yes Yes Yes
FLAC Lossless 1 Hz to 1.04857 MHz variable 4, 8, 16, 24, (32) 4.3ms - 92ms (46.4ms typical) No Yes Yes Yes: Up to 8 channels
GSM-HR Lossy 8 kHz 5.6 kbit/s 13 25ms Yes No No No
GSM-FR Lossy 8 kHz 13 kbit/s 13 20-30ms Yes No No No
GSM-EFR Lossy 8 kHz 12.2 kbit/s 13 20-30ms Yes No No No
iLBC Lossy 8 kHz 13.33, 15.20 kbit/s 16 30, 20ms Yes No No No
Monkey's Audio Lossless 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48 kHz variable  ?  ? No Yes Yes No
MP3 (MPEG-1, 2, 2.5 Audio Layer III) Lossy 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48 kHz 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 192, 224, 256, 320 kbit/s Any (typically uses fp internally) >100ms Yes Yes Yes: Dual, Mid/Side, Intensity No
MPEG-1 Audio Layer II (MP2) Lossy 32, 44.1, 48 kHz 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384 kbit/s varies Yes Yes: but decoders are not required to support it Yes No
MPEG-2 Audio Layer II (MP2) Lossy 16, 22.05, 24 kHz 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 kbit/s varies Yes Yes: but decoders are not required to support it Yes Yes: up to 5 full range audio channels and an LFE-channel
Musepack Lossy 32, 37.8, 44.1, 48 kHz 3 to 1300 kbit/s 8 to 32  ? No Yes Yes No
RealAudio Lossless, Lossy Varies (see article) Varies (see article) Varies (see article) Varies Yes Yes Yes Yes: Up to 6 channels
Speex Lossy, Speech 8, 16, 32 (, 48) kHz 2.15 to 24.6 kbit/s (NB); 4 to 44.2 kbit/s (WB) 16 30ms (NB) 34ms (WB) Yes Yes Yes: Intensity Yes
TAK Lossless 8 kHz to 192 kHz variable 8, 16, 24  ? No Yes Yes Yes: Up to 16 channels
Vorbis (Ogg) Lossy 1 Hz to 200 kHz variable Any (typically uses fp internally) >100ms Yes/ABR Yes Yes: Dual, Lossless, Phase, Point (Intensity) Yes: Up to 255 channels
WavPack Lossless, Lossy, Hybrid 1 Hz to 16.777216 MHz variable in lossless mode; 196 kbit/s and up in lossy mode (for CD audio) varies in lossless mode; 2.2 minimum in lossy mode  ? Yes Yes Yes Yes: Up to 16 channels
Windows Media Audio Lossless, Lossy 8, 11.025, 16, 22.05, 32, 44.1, 48, 88.2, 96 kHz 4 to 768kbit/s, variable in lossless encoding 16, 24 for lossless mode, any in lossy mode (typically uses fp internally) >100ms Yes Yes Yes Yes: Up to 8 channels (WMA Professional), Up to 6 channels (WMA Lossless)
Technical Details of Audio Compression Formats
Audio compression format Algorithm Sample Rate Bit rate[9] Bits per sample Latency CBR VBR Stereo Multichannel
G.711 companding A-law or μ-law, PCM, Lossy 8 kHz 64 kbit/s 8 bit Yes No No No
G.711.1 MDCT, A-law, u-law, Lossy 8 or 16 kHz 64, 80, 96 kbit/s 8-12 bit 11.875 ms Yes No No No
G.718 CELP, MDCT, Lossy 8 or 16 kHz 8, 12, 12.65, 16, 24, 32 kbit/s 42.875 ms - 43.875 ms Yes No No No
G.719 Lossy 48 kHz 32-128 kbit/s
(Rates between 32 and 88 kbit/s shall be a multiple of 4 kbit/s; 88-128 kbit/s - a multiple of 8 kbit/s.)
40 ms Yes No Yes: only in MPEG-4 Part 12 container Yes: only in MPEG-4 Part 12 container
G.721 ADPCM, Lossy 8 kHz 32 kbit/s Yes No No No
G.722 sub-band ADPCM, Lossy 16 kHz 64 kbit/s
(comprises 48, 56 or 64 kbit/s audio and 16, 8 or 0 kbit/s auxiliary data)
14 bit 4 ms Yes No No No
G.722.1 Modulated Lapped Transform, (based on Siren Codec), Lossy 16 or 32 kHz 24, 32, 48 kbit/s 40 ms Yes No No No
G.722.2 multi-rate wideband ACELP (AMR-WB), Lossy 16 kHz 6.60-23.85 kbit/s
(6.60, 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbit/s)
14 bit 25 ms Yes No Yes: only in MPEG-4 Part 12 container No
G.723 ADPCM, Lossy 8 kHz 24 or 40 kbit/s Yes No No No
G.723.1 MP-MLQ, ACELP, Lossy 8 kHz 5.3, 6.3 kbit/s 37.5 ms Yes No No No
G.726 ADPCM, Lossy 8 kHz 16, 24, 32, 40 kbit/s Yes No No No
G.727 ADPCM, Lossy 8 kHz 16, 24, 32, 40 kbit/s Yes No No No
G.728 low-delay CELP, Lossy 8 kHz 16 kbit/s 0.625 ms Yes No No No
G.729 CS-ACELP, Lossy 8 kHz 8 kbit/s 15 ms Yes No No No
G.729D CS-ACELP, Lossy 8 kHz 6.4 kbit/s Yes No No No
G.729E CS-ACELP, Lossy 8 kHz 11.8 kbit/s 15 ms Yes No No No
G.729.1 CELP, TDBWE, TDAC, Lossy 8 or 16 kHz 8-32 kbit/s
(12 layers; 4 kbit/s steps)
48.9375 ms Yes Yes No No

Notes

  • The latency listed here is the total delay (frame size, plus all lookahead) at the normal operating sample rate (typically 44.1kHz).

Notes & references

  1. 1.0 1.1 1.2 FFmpeg General Documentation - AMR external library, Retrieved on 2009-07-08
  2. 2.0 2.1 2.2 Android AMR codecs, Retrieved on 2009-07-08
  3. Cisco IP Communicator 7.0 Data sheet - support for iLBC Retrieved on 2009-07-08
  4. Skype Community, Current Codec Uses, Retrieved on 2009-07-08
  5. Windows Media Encoder
  6. An open-source decoder for ALAC has been reverse engineered.
  7. 7.0 7.1 The ffmpeg project has reverse engineered some codecs of the RealAudio and Windows Media Audio (DivX Audio v1 and DivX Audio v2) formats. This enables their use on any POSIX compatible system.
  8. Microsoft has outsourced their WMA support on Mac OS X to Telestream, Inc. who created and maintain Windows Media Components for QuickTime, replacing Windows Media Player for Mac OS.
  9. 9.0 9.1 Lossless compression is always VBR
  10. MPEG 2 AAC was limited to a 96 kHz sampling rate, however, with MPEG 4 AAC, a later version part of the MPEG 4 specification, the maximum sampling rate has been increased to 192 kHz.
  11. Apple Lossless Information

See also

File:Free Software Portal Free software portal

External links


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