[Speex-dev] Stream Synchronization for Echo Cancellation

Aymeric Moizard jack at atosc.org
Thu Nov 2 02:07:04 PST 2006

On Thu, 2 Nov 2006, Jean-Marc Valin wrote:

>> Can you explain why?
>> My problem is not at all related to local input/output non-synchronised
>> clocks: my problem is really between non-synchronised clock between one
>> PC and another...
> What happens is that my jitter buffer is designed without any explicit
> clock. The pace at which you get data from it is assumed to be the local
> clock. The jitter buffer is designed to buffer just enough packets to
> prevent most packets from arriving late. It means that when we are in
> steady-state conditions (jitter not changing). In that case:
> 1) If the packets arrive to fast (remote clock is faster), then it will
> discard packets once in a while to maintain the optimal buffer size.
> 2) If the packets arrive too slow, interpolation will happen because the
> buffer becomes too small.

Interpolation? -> this seems very interesting. I have to take a closer
look at it.

Tks jean-marc,

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