Comparison of audio coding formats
Appearance
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.
General information
Audio compression format | Creator | First public release date | Latest stable version | Encoder Cost | Player Cost | Proprietary implementations (codecs) | Open-source implementations (codecs) | Application (besides consumer audio) | Music reproduction (consumer audio) | telephony app | Lossless audio compression | Patented | DRM |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
AAC | ISO/IEC MPEG Audio Committee | 1997 | ISO/IEC 14496-3 | Non-free[1] | Non-free[1] | FAAC (encoding only), iTunes, Nero Digital Audio | FAAD2 (decoding only), FFmpeg, Android OpenCORE AAC (decoding only)[2] | Digital TV service, internet streaming | Yes | No | No | Non-free Yes | Non-free FairPlay (.m4p Only, Discontinued) |
AC-3 | Dolby Laboratories | 1992 | ? | Non-free | Non-free | DVD players, Digital television | FFmpeg, liba52 (decoding only), Aften (encoding only), libavc (2.0 channels max) | Theatrical movie presentation, Digital TV service & home-video (personal recorders, DVD, etc.) | No | No | No | Non-free Yes | ? |
ALAC | Apple Computer | 2004-04-28 | QuickTime 7.6 | Free | Free | QuickTime, iTunes, Real Player | MacOSforge, FFmpeg | - | Music archival | Yes | Yes | ? | Possible, but never Implemented |
ALS | ISO/IEC MPEG Audio Committee | 2005 | ISO/IEC 14496-3 | Free | Free | mp4als | FFmpeg (decoding only) | - | - | No | Yes | Non-free Yes | ? |
AMR | 3GPP | 1999-06-22 | ETSI TS 126 071 V9.0.0 (2009) | Non-free[3][4] | Non-free[3][4] | QuickTime, Real Player | FFmpeg (decoding only), FFmpeg with OpenCORE libraries[5], Android[6] | voice recording | No | Yes | No | Non-free Yes | No |
AMR-WB (G.722.2) |
3GPP | 2001-04-10 | ETSI TS 126 190 V8.0.0 (2009-01) | Non-free | Non-free | QuickTime, Real Player | FFmpeg (decoding only)[5], FFmpeg with VisualOn libraries, Android (decoding only)[6] | voice recording | No | Yes | No | Non-free Yes | No |
AMR-WB+ | 3GPP | 2004-06-14 | ETSI TS 126 290 V8.0.0 (2009-01) | Non-free[7][8] | Non-free[7][8] | ? | ? | voice recording | Yes | Yes | No | Non-free Yes | No |
apt-X | APTX | 1989 | 2007 | Non-free | Non-free | broadcast audio codecs: Systembase, 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 | Yes | No | Non-free Yes | No |
ATRAC | Sony Corp. | 1991 | ATRAC3plus | Non-free | Non-free | 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, Theatrical movie presentation | - | No | Yes | Non-free Yes | Non-free Yes |
CELT | Xiph.Org Foundation, Jean-Marc Valin | 2007-12-08 | 0.11.1 | Free | Free | libcelt, FFmpeg with libcelt library (decoding only) | Speech, VoIP, Low latency, Studio/transmitter link, wireless audio | Yes | Yes | No | No | No | |
FLAC | Xiph.Org Foundation, Josh Coalson | 2001-07-20 | 1.2.1 | Free | Free | FLAC[9], Flake (encoding only)[10], FFmpeg | - | - | Yes | Yes | 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 | No | Yes | No | No | No |
G.722 | ITU-T | 1988-11 | Free | Free | various proprietary VoIP software | Asterisk (PBX), QuteCom, FFmpeg | voice recording | No | Yes | No | No | No | |
G.722.1 | ITU-T | 1999-09 | G.722.1 (05/05) | Free[11][12] | Free[11][12] | various proprietary VoIP software | FreeSWITCH[13], pjsip, etc | voice recording | No | Yes | No | Non-free Yes | No |
G.722.2 (AMR-WB) |
ITU-T (adopted directly from 3GPP) | 2002-01 | G.722.2 (07/03) | Non-free | Non-free | QuickTime, Real Player | FFmpeg (decoding only)[5], FFmpeg with VisualOn libraries, Android (decoding only)[6] | voice recording, audio | No | No | No | Non-free Yes | No |
G.723.1 | ITU-T | 1996-03 | G.723.1 (05/06) | Non-free | Non-free | various proprietary VoIP software | FFmpeg | voice recording | No | Yes | No | Non-free Yes | No |
G.726 | ITU-T | 1990-12 | Free | Free | various proprietary VoIP software | FFmpeg, Ekiga and other VoIP software | voice recording | No | Yes | No | No | No | |
G.728 | ITU-T | 1992-09 | Non-free | Non-free | various proprietary VoIP software | voice recording | No | Yes | No | Non-free Yes | No | ||
G.729 | ITU-T | 1996-03 | G.729 (01/07) | Non-free | Non-free | various proprietary VoIP software | FFmpeg (decoding only) | voice recording | No | Yes | No | 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 (decoding only), FFmpeg with external library libgsm, Ekiga and other VoIP software | voice recording | No | Yes | No | ? | No | |
iLBC | Global IP Solutions | 2002 | Free | Free | Cisco IP Communicator[14], old versions of Skype[15] | Ekiga, Asterisk (PBX) and other VoIP software | voice recording | No | Yes | No | No?[16] | No | |
iSAC | Global IP Solutions | ? | Free | Free | Yahoo! Messenger | WebRTC | voice recording | No | Yes | No | Free[17] | ? | |
Monkey's Audio | Matthew T. Ashland | 2000+ | 4.06 | Free | Free | Monkey's Audio | FFmpeg (decoding only) | - | - | No | Yes | ? | 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) | - | Yes | No | No | 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-free | Non-free | various DVD software, video software, audio software | TooLAME (encoding only), TwoLAME (encoding only), FFmpeg | - | Yes | No | No | Non-free Yes[18][dubious – discuss] | ? |
Musepack | Frank Klemm/MDT | 1997 | 1.30 (2009-04-02) | Free | Free | Musepack[19], FFmpeg (decoding only) | - | Yes | No | No | Maybe[20] | ? | |
Nellymoser Asao | Nellymoser Inc. | 2002 | ? | Non-free | Non-free | Adobe Flash, Flash Player | FFmpeg | voice recording | No | No | No | Non-free Yes | ? |
Opus | IETF | ? | ? | Free | Free | ? | Yes | VoIP | Yes | Yes | No | Eventually Free[21] | ? |
Shorten | Tony Robinson | 1999-06-02 | 1. | Free | Free | Shorten | FFmpeg (decoding only) | - | - | No | Yes | No | No |
SILK | Skype Limited | 2009-01-07 | Free | Free | Skype | voice recording | No | No | No | Non-free Yes | ? | ||
Siren 7 | PictureTel Corp. (now Polycom Inc.) | 1999 | ?[11][12] | ?[11][12] | Microsoft Office Communicator | FreeSWITCH (libg722_1[22], aMSN (libsiren - part of libmsn)[23][24] | voice recording | No | Yes | No | Non-free Yes | ? | |
Speex | Xiph.Org Foundation, Jean-Marc Valin | 2003-03-24 | 1.1.12 | Free | Free | Flash Player 10 | Speex[25], FFmpeg with libspeex library | voice recording | No | Yes | No | No | No |
SVOPC | Skype Limited | 2007 | ? | ? | Skype | voice recording | No | Yes | No | Non-free Yes | ? | ||
TwinVQ | Nippon Telegraph and Telephone | 1996 (?) | Non-free | Non-free | Winamp with VQF Plugin, NTT TwinVQ player/encoder, Yamaha SoundVQ player, Nero Media Player | FFmpeg (decoding only)[26] | speech | Yes | No | No | Non-free Yes | ? | |
Vorbis (Ogg) | Xiph.Org Foundation | 2000-05-11 | 1.3.2 | Free | Free | libvorbis[27], aoTuV[28], FFmpeg | - | Yes | No | No | No | No | |
WavPack | Conifer Software | 1998 | 4.60.1 | Free | Free | WavPack[29], FFmpeg (decoding only) | - | - | Yes | Yes | No | No | |
Windows Media Audio | Microsoft | 1999 | 11.0 | Free Windows Media Encoder[30] | Free for licensees of the Windows operating system [31] | Windows Media Player, Windows Media Encoder | FFmpeg (decoding only for Pro and Voice, Lossless is not supported) | internet streaming | Yes | No | Yes | Non-free Yes | Non-free[32] |
Audio compression format | Creator | First public release date | Latest stable version | Encoder Cost | Player Cost | Proprietary implementations (codecs) | Open-source implementations (codecs) | Application | App: Music | App: telephony | Lossless audio compression | Patented | DRM |
Notes
- The 'Music' category is merely a guideline on commercialized uses of a particular format, not a technical assessment of its capabilities. (For example, in terms of marketshare, MP3 and AAC dominate the personal audio market, though many other formats are comparably well suited to fill this role from a purely technical standpoint.)
- 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.
- Latest stable version is that of specification or reference tools.
- If there happens to be OSI licensed software available for a particular format, 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 format, one might be able to use the codec free of charge.
- 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
Codec | Windows | Mac OS X | Linux | BSD | Unix | Palm OS | Symbian OS | Rockbox |
---|---|---|---|---|---|---|---|---|
AAC | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
ALAC[33] | Yes | Yes | Yes | Yes | Yes | No | No | Yes |
apt-X | Yes | Yes | Yes | Yes | Yes | No | No | No |
CELT | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
FLAC | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Monkey's Audio | Yes | Yes | Yes | Yes | Yes | No | No | Yes |
MP3 | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Musepack | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Opus | Yes | Yes | Yes | Yes | Yes | No | No | No |
RealAudio[34] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Speex | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Vorbis | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
WavPack | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
WMA[34] | Yes | Yes[35] | Partial | Partial | Partial | Yes | Yes | Yes |
Multimedia Frameworks Support
Technical details
Audio compression format | Algorithm | Sample Rate | Bit rate | Latency | CBR | VBR | Stereo | Multichannel |
---|---|---|---|---|---|---|---|---|
AAC | MDCT, Hybrid Subband (AAC-HE) | 8 kHz to 192 kHz[37] | 8 to 529 kbit/s (stereo) | 20−405ms[38] | Yes | Yes | Yes: Dual, Mid/Side, Intensity, Parametric | Yes: Up to 48 channels |
AC3 | MDCT | 32, 44.1, 48 kHz | 32 to 640 kbit/s | 40.6ms | Yes | No | Yes | Yes: Up to 6 channels |
AMR | ACELP | 8 kHz | 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.20, 12.20 kbit/s | 25ms | Yes | Yes | No | No |
AMR-WB (G.722.2) |
ACELP | 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) |
25ms | Yes | Yes | Yes: only in MPEG-4 Part 12 container | No |
AMR-WB+ | ACELP | 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) | 60–90 ms | Yes | Yes | Yes | No |
apt-X | Subband | 24 kHz to 48 kHz (stereo) | 192 kbit/s to 384 kbit/s (stereo) | 2ms | Yes (4:1) | No | Yes | Yes: Up to 8 channels |
ATRAC1 | MDCT-Hybrid Subband | Various | 292 kbit/s | >100ms | Yes | No | Yes: Dual Only | No |
ATRAC3 | MDCT-Hybrid Subband | Various | 132/66 kbit/s | >100ms | Yes | No | Yes: Dual (LP2), Mid/Side (LP4) | No |
ATRAC3plus | MDCT-Hybrid Subband | Various | 48-352 kbit/s | >100ms | Yes | ? | Yes | ? |
CELT | MDCT | 32 to 96 kHz | 24 kbit/s[39] to >1 Mbit/s | 2ms - 14.5ms (8.9ms typical) | Yes | No | Yes | Yes |
GSM-HR | VSELP | 8 kHz | 5.6 kbit/s | 25ms | Yes | No | No | No |
GSM-FR | RPE-LTP | 8 kHz | 13 kbit/s | 20-30ms | Yes | No | No | No |
GSM-EFR | ACELP | 8 kHz | 12.2 kbit/s | 20-30ms | Yes | No | No | No |
HVXC | Speech | 8 kHz | 2 or 4 kbit/s | 36ms | Yes | Yes | No | No |
iLBC | Block Independent LPC | 8 kHz | 13.33, 15.20 kbit/s | 30, 20ms | Yes | No | No | No |
iSAC | Transform coding | 16 kHz or 32 kHz | 10 to 52 kbit/s | 33 to 63ms | Yes | Yes | No | No |
MP3 (MPEG-1, 2, 2.5 Audio Layer III) | MDCT, Hybrid Subband | 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 | >100ms | Yes | Yes | Yes: Dual, Mid/Side, Intensity | No |
MPEG-1 Audio Layer II (MP2) | Subband | 32, 44.1, 48 kHz | 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384 kbit/s | Yes | Yes: but decoders are not required to support it | Yes | No | |
MPEG-2 Audio Layer II (MP2) | Subband | 16, 22.05, 24 kHz[40][41] | 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 kbit/s[40] | 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 | Subband | 32, 37.8, 44.1, 48 kHz | 3 to 1300 kbit/s | ? | No | Yes | Yes | Yes: up to 8 channels |
Opus | Hybrid (CELP+MDCT) | 8 to 48 kHz | 6 to 510 kbit/s | 5 to 65.2 ms | Yes | Yes | Yes | ? |
RealAudio | MDCT, | Varies (see article) | Varies (see article) | Varies | Yes | Yes | Yes | Yes: Up to 6 channels |
SILK | LTP | 8, 12, 16, 24 kHz | 6 to 40 kbit/s | 25ms | Yes | ? | ? | ? |
Siren 7 | derived from PT716plus, MLT | 16 kHz | 16, 24, 32 kbit/s | 40ms | Yes | No | No | No |
Siren 14 | MLT | 32 kHz | 24, 32, 48 kbit/s (mono), 48, 64, 96 kbit/s (stereo) | 40ms | Yes | No | Yes | No |
Siren 22 | MLT | 48 kHz | 32, 48, 64 kbit/s (mono), 64, 96, 128 kbit/s (stereo) | 40ms | Yes | No | Yes | No |
Speex | CELP | 8, 16, 32 (, 48) kHz | 2.15 to 24.6 kbit/s (NB); 4 to 44.2 kbit/s (WB) | 30ms (NB) 34ms (WB) | Yes | Yes | Yes: Intensity | Yes |
VMR-WB | ACELP | 16 kHz | 8.55, 4.0, 0.8, 13.3, 6.2, 2.7, 1.0 | 33.75ms | Yes | Yes | ? | ? |
Vorbis (Ogg) | MDCT | 1 Hz to 200 kHz | variable | >100ms | Yes/ABR | Yes | Yes: Dual, Lossless, Phase, Point (Intensity) | Yes: Up to 255 channels |
WavPack Lossy | Prediction, Quantization | 1 Hz to 16.777216 MHz | 196 kbit/s and up in lossy mode (for CD audio) | ? | Yes | Yes | Yes | Yes: Up to 256 channels |
Windows Media Audio Standard | MDCT | 8, 11.025, 16, 22.05, 32, 44.1, 48 kHz | 8 to 768kbit/s | >100ms | Yes | Yes | Yes | No |
Windows Media Audio Pro | MDCT | 8, 11.025, 16, 22.05, 32, 44.1, 48, 88.2, 96 kHz | 4 to 768kbit/s | >100ms | Yes | Yes | Yes | Yes: At least 8 channels, expandable |
Audio compression format | Algorithm | Sample Rate | Bits per sample | Latency | Stereo | Multichannel |
---|---|---|---|---|---|---|
ALAC | Lossless | 1 Hz to 384000 Hz | 16, 20, 24, 32[42] | ? | Yes | Yes: Up to 8 channels |
FLAC | Lossless | 1 Hz to 655350 Hz | 8, 16, 20, 24, (32) | 4.3ms - 92ms (46.4ms typical) | Yes | Yes: Up to 8 channels |
Monkey's Audio | Lossless | 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48 kHz | ? | ? | Yes | No |
RealAudio Lossless | Lossless | Varies (see article) | Varies (see article) | Varies | Yes | Yes: Up to 6 channels |
True Audio | Lossless | 0–4 GHz | 1 to > 64 | ? | Yes | Yes: Up to 65535 channels |
WavPack Lossless | Lossless, Hybrid | 1 Hz to 16.777216 MHz | varies in lossless mode; supports 32-bit float input; 2.2 minimum in lossy mode | ? | Yes | Yes: Up to 256 channels |
Windows Media Audio Lossless | Lossless | 8, 11.025, 16, 22.05, 32, 44.1, 48, 88.2, 96 kHz | 16, 24 | >100ms | Yes | Yes:Up to 6 channels |
Audio compression format | Algorithm | Sample Rate | Bit rate[43] | 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 | 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, (10 kbit/s 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 44.1 kHz).
See also
- Codec listening test
- Comparison of media players
- List of video players (software)
- List of codecs
- Comparison of video codecs
- Comparison of container formats
Notes & references
- ^ a b variable price
- ^ OpenCORE Media Framework, Retrieved 2009-08-13
- ^ a b VoiceAge Corporation (2007-10-14). "AMR Licensing Terms". Archived from the original on 2007-10-14. Retrieved 2009-09-12.
- ^ a b VoiceAge Corporation (2007-06). "AMR Licensing Terms". VoiceAge Corporation. Retrieved 2009-09-12.
{{cite web}}
: Check date values in:|date=
(help) - ^ a b c FFmpeg General Documentation - AMR external library, Retrieved on 2009-07-08
- ^ a b c Android AMR codecs, Retrieved on 2009-07-08
- ^ a b VoiceAge Corporation (2007-10-14). "AMR-WB+ Licensing Terms". Archived from the original on 2007-10-14. Retrieved 2009-09-12.
- ^ a b VoiceAge Corporation (2006-11). "AMR-WB+ Licensing Terms". VoiceAge Corporation. Retrieved 2009-09-12.
{{cite web}}
: Check date values in:|date=
(help) - ^ FLAC website, Retrieved 2009-09-01
- ^ Flake website, Retrieved 2010-12-17
- ^ a b c d Polycom, Inc. "Siren7/Siren14/G.719 License info". Polycom, Inc. Retrieved 2009-09-07.
- ^ a b c d Polycom, Inc. "Polycom Siren 14/G 722.1C FAQs - What are the terms on the free license?". Polycom, Inc. Retrieved 2009-09-07.
- ^ libg722_1
- ^ Cisco IP Communicator 7.0 Data sheet - support for iLBC Retrieved on 2009-07-08
- ^ Skype Community, Current Codec Uses, Retrieved on 2009-07-08
- ^ iLBC License — GIPS
- ^ WebRTC free license from Google, including iSAC and iLBC
- ^ Kuro5hin.org (2008-07-20) Patent Status of MPEG-1,H.261 and MPEG-2, Retrieved 2009-09-05
- ^ Musepack website, Retrieved 2009-09-01
- ^ [1]
- ^ https://datatracker.ietf.org/ipr/1525/
- ^ freeswitch.org libg722_1 - README, Retrieved 2009-09-08
- ^ "Libmsn - is a reusable, open-source, fully documented library for connecting to Microsoft's MSN Messenger service". Libmsn project at Sourceforge.net. 2009. Retrieved 2009-09-07.
- ^ KaKaRoTo (2008-02-12) MSN Protocol documentation, Pidgin.im mailinglist, Retrieved 2009-09-08
- ^ Speex website, Retrieved 2009-09-01
- ^ FFmpeg (2009-08-24) News - August 24, 2009 - TwinVQ decoding in upcoming stable version, Retrieved 2009-10-07
- ^ Vorbis website, Retrieved 2009-09-01
- ^ aoTuV website, Retrieved 2009-09-01
- ^ WavPack website, Retrieved 2009-09-01
- ^ Windows Media Encoder
- ^ http://www.microsoft.com/windows/windowsmedia/licensing/licensing.aspx
- ^ Optional
- ^ An open-source decoder for ALAC has been reverse engineered.
- ^ 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.
- ^ 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.
- ^ a b c Monogram DS filters, Retrieved 2009-10-22
- ^ 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.
- ^ Algorithmic delay and synchronization in MPEG audio codecs
- ^ ""Codec Feature Comparison"".
{{cite web}}
: Text "accessdate December 14th, 2011" ignored (help) - ^ a b Predrag Supurovic (1998-09). "MPEG Audio Frame Header". Retrieved 2009-07-11.
{{cite web}}
: Check date values in:|date=
(help) - ^ ISO/IEC JTC1/SC29/WG11 - Audio Subgroup. "MPEG Audio FAQ Version 9, MPEG-1 and MPEG-2 BC". Retrieved 2010-02-27.
{{cite web}}
: CS1 maint: numeric names: authors list (link) - ^ The Apple Lossless Format
- ^ Lossless compression is always VBR
External links
- Comparative test April, 2004
- EBU subjective listening tests on low-bitrate audio codecs
- Hydrogenaudio comparison of lossless formats
- Tsabary, Eldad. “A Survey of Audio Coders for Electronic-Art Music.” eContact! 9.4 — Perte auditive et sujets connexes / Hearing (Loss) and Related Issues (May 2007). Montréal: CEC.
- Rodman, Jeffrey "VoIP to 20 kHz: Codec Choices for High Definition Voice Telephony" (July, 2008)