Internet speech Audio Codec (ISAC)

 

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Internet Speech Audio Codec (iSAC)

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

 

ISAC 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	[1]

 

Internet Speech Audio Codec(ISAC) Is
Wideband
Speech codec, developed
Global IP Solutions (GIPS) (acquired
Google Inc 2011<sup>[2][3]). It is suitable
VoIP applications and
Streaming audio. The encoded blocks have to be encapsulated in a suitable protocol for transport, eg.

RTP.</sup>

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

 

Parameters and features

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