[Vorbis-dev] Algorithmic delay

[Tor-Einar Jarnbjo]

Steve Underwood schrieb:
> I'm wonder what the delay would be, using vorbis for high quality 
> conferencing VoIP.
It dependes on the block sizes used by the encoder and the sample rate. 
Using those parameters, the algorithmic delay can be calculated as 
1.5*bsmax/samplerate. For example for block sizes 256 and 2048 (which 
are commonly used) and a sample rate of 44100sps, the delay is 
1.5*2048/44100 = 70ms.

For low-delay applications, it would at least theoretically be possible 
to force the encoder to use smaller block sizes at the cost of a worse 
quality/bitrate ratio, but I don't think any vorbis encoder is able to 
do that. Allowed block sizes are from 64 to 8192, so the minimum 
theoretical delay at 44100sps is only 2.2ms, but with so small block 
sizes, the compression ratio will probably be minimal, if you want to 
keep any quality.

Tor