Software:internet Speech Audio Codec
From HandWiki
Short description: Audio codec standard
| Internet media type | audio/isac[1] |
|---|---|
| Developed by | Global IP Solutions, now Google Inc |
| Type of format | Audio compression format |
| 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 |
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
See also
- iLBC
- Opus (audio codec)
- SILK
- G.722
- Speex
- List of codecs
References
- ↑ 1.0 1.1 1.2 Grand, Tina le; Jones, Paul; Huart, Pascal; Shabestary, Turaj Zakizadeh; Alvestrand, Harald T. (2013). "RTP Payload Format for the iSAC Codec". https://tools.ietf.org/html/draft-ietf-avt-rtp-isac-04.
- ↑ Dana Blankenhorn (2010-05-18). "Why Google bought Global IP Solutions". http://www.zdnet.com/blog/open-source/why-google-bought-global-ip-solutions/6501.
- ↑ "iLBC Freeware". http://www.webrtc.org/ilbc-freeware.
- ↑ webrtc.org/faq/#what-is-the-isac-audio-codec .
- ↑ webrtc.org/license/additional-ip-grant/.
- ↑ 6.0 6.1 "WebRTC FAQ - What are the parameters of iSAC?". http://sites.google.com/site/webrtc/faq#TOC-What-are-the-parameters-of-iSAC-.
- ↑ 7.0 7.1 "WebRTC components". http://www.webrtc.org/reference/webrtc-components#TOC-iSAC.
External links
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