[Speex-dev] speex voice seems to be bit breaking over long
Jean-Marc.Valin at USherbrooke.ca
Mon Apr 18 09:28:16 PDT 2005
> Ok, what you suggest sound logical to me. Currently, I
> have done a small trick to prevent this problem. What
> I did is that whenever windows request a voice packet
> from me and if I do not have the voice packet, I
> repeat the previous packet. Hence, all the breaking
> portion is filled with previous packet. This trick
> seems to work so far. I am not sure what is the side
Actually, Speex has Packet Loss Concealment (PLC) builtin. If a packet
is missing, instead of repeating the previous one, just try decoding by
passing NULL instead of the SpeexBits struct.
> I think jitter buffering is more correct way to solve
> this problem but I think this is not so easy. Is there
> got any source code to reference from?
Look for the speex_jitter.h header.
> --- "Kleijn, J.S. de" <J.S.d.Kleijn at student.tue.nl>
> > Hi,
> > You should implement a jitter buffer, this buffers
> > the audio to prevent the 'breaking'.
> > My VoIP application called VoIPerized has a jitter
> > buffer. You can try it to see if you then don't
> > experience the breaking of the voice.
> > Greetings Jeroen de Kleijn
> > -----Oorspronkelijk bericht-----
> > Van: speex-dev-bounces at xiph.org namens Tay YueWeng
> > Verzonden: ma 18-4-2005 11:28
> > Aan: speex-dev at xiph.org
> > CC:
> > Onderwerp: [Speex-dev] speex voice seems to be bit
> > breaking over long distance.
> > Dear all,
> > I have implemented speex. Under LAN environment,
> > everything is working fine. However, when the
> > source
> > and destination is about 20 hrs away, with ping
> > response time of about 800ms, the voice is
> > breaking.
> > Breaking means you can not hear a smooth voice.
> > Like
> > the voice is being "chopped" into many pieces.
> > The amount of packet lost is less than 10%. I have
> > tried 8KHz, 16KHz, 32KHz. The bigger it gets, the
> > more
> > lousy the quality. I believe I have enough
> > bandwidth
> > since the packet lost is less than 10%. The only
> > factor that could affect the quality is may be
> > delayed.
> > Any one have any idea of what is wrong?
> > Regards,
> > YueWeng
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Jean-Marc Valin <Jean-Marc.Valin at USherbrooke.ca>
Université de Sherbrooke
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