[Speex-dev] Algorithmic Delay

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Sun Dec 24 18:21:28 PST 2006

The 34 ms includes everything: frame size, encoder latency/lookahead and
decoder latency/lookahead. It means that "in theory" (everything else
ideal), you could get 34 ms end-to-end latency with the codec. Of
course, in practice, you need to add network latency, soundcard
buffering and the jitter buffer. But those are codec-independent anyway.


Tom Lukasiak a écrit :
> Hi,
> I was hoping to get some clarification on the meaning of algorithmic
> latency in Speex.
> For wideband signals, algorithmic delay is specified to be 34 ms (20
> ms is the frame size and 14 ms is the lookahead).
> Does this number (34 ms) account for the double-buffering on the
> input?
> Assuming that the computation time and sound wave propagation time
> are negligible, should I expect compressed audio to be ready for
> network transmission 34 ms after the sound is created or 54 ms (the
> algorithmic delay of 34 ms + 20 ms for double-buffering at the ADC)?
> Thanks, Tom
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