Internet Speech Audio Codec
internet Speech Audio Codec is a wideband speech codec, developed by Global IP Solutions . 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, which includes a royalty-free license for iSAC when using the WebRTC codebase.
Parameters and features
- Sampling frequency of 16 kHz or 32 kHz
- Adaptive and variable bit rate of 10 kbit/s to 32 kbit/s or 10 kbit/s to 52 kbit/s
- 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