Internet Speech Audio Codec

Codec
Developer(s)	Global IP Solutions, now Google Inc
Written in	C
Operating system	Cross-platform
Type	Audio codec, reference implementation
License	formerly proprietary, now 3-clause BSD
Website	webrtc.org

internet Speech Audio Codec
Internet media type	audio/isac
Developed by	Global IP Solutions, now Google Inc
Type of format	Audio compression format

internet Speech Audio Codec (iSAC) is a wideband speech codec, developed by Global IP Solutions (GIPS) (acquired by Google Inc in 2011).^[2]^[3] It is suitable for VoIP applications and streaming audio. The encoded blocks have to be encapsulated in a suitable protocol for transport, e.g. RTP.

It is one of the codecs used by AIM Triton, the Gizmo5, QQ, and Google Talk. It was formerly a proprietary codec licensed by Global IP Solutions. As of June 2011, it is part of open source WebRTC project,^[4] which includes a royalty-free license for iSAC when using the WebRTC codebase.^[5]

Parameters and features

Sampling frequency of 16 kHz (wideband) or 32 kHz (superwideband)^[1]^[6]^[7]
Adaptive and variable bit rate of 10 kbit/s to 32 kbit/s (wideband) or 10 kbit/s to 52 kbit/s (superwideband)^[1]^[6]^[7]
Adaptive packet size 30 to 60 ms
Complexity comparable to G.722.2 at comparable bit-rates
Algorithmic delay of frame size plus 3 ms

References

^ ^a ^b ^c Grand, Tina le; Jones, Paul; Huart, Pascal; Shabestary, Turaj Zakizadeh; Alvestrand, Harald T. (2013). "RTP Payload Format for the iSAC Codec". Retrieved 2016-04-30.
^ Dana Blankenhorn (2010-05-18). "Why Google bought Global IP Solutions". ZDNet. Retrieved 2011-06-23.
^ "iLBC Freeware". Archived from the original on 2011-07-05. Retrieved 2011-06-23.
^ webrtc.org/faq/#what-is-the-isac-audio-codec Archived 2011-06-07 at the Wayback Machine.
^ webrtc.org/license/additional-ip-grant/.
^ ^a ^b "WebRTC FAQ - What are the parameters of iSAC?". Archived from the original on 2016-11-17. Retrieved 2011-06-23.
^ ^a ^b "WebRTC components". Archived from the original on 2011-06-28. Retrieved 2011-06-23.

External links

WebRTC codecs - GIT- source code for iSAC and other codecs

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[rfc-draft-1] Grand, Tina le; Jones, Paul; Huart, Pascal; Shabestary, Turaj Zakizadeh; Alvestrand, Harald T. (2013). "RTP Payload Format for the iSAC Codec". Retrieved 2016-04-30.

[2] Dana Blankenhorn (2010-05-18). "Why Google bought Global IP Solutions". ZDNet. Retrieved 2011-06-23.

[3] "iLBC Freeware". Archived from the original on 2011-07-05. Retrieved 2011-06-23.

[4] webrtc.org/faq/#what-is-the-isac-audio-codec Archived 2011-06-07 at the Wayback Machine.

[5] webrtc.org/license/additional-ip-grant/.

[webrtc-faq-6] "WebRTC FAQ - What are the parameters of iSAC?". Archived from the original on 2016-11-17. Retrieved 2011-06-23.

[webrtc-isac-7] "WebRTC components". Archived from the original on 2011-06-28. Retrieved 2011-06-23.

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Internet media type	audio/isac^[1]
Developed by	Global IP Solutions, now Google Inc
Type of format	Audio compression format

Parameters and features

See also

References

External links