[Speex-dev] Jitter buffer

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Wed Nov 10 20:31:52 PST 2004


> I believe it is adaptive, but no, I haven't used it, because it's
> coupled only to the speex codec.  We're working on a generic
> application and codec-independent jitter buffer algorithm, for use in
> asterisk and iaxclient (at least).  Some information is available at
> http://www.voip-info.org/tiki-index.php?page=Asterisk%20new%
> 20jitterbuffer

Yes, this jitter buffer is adaptive. There are still some improvements
left to do (e.g. making sure packets are dropped/interpolated during
silent periods), but it's already working good. 

As for being Speex-dependent, I'd say yes and no. It calls speex_decode,
which is a Speex "virtual" function, so it would be rather simple to
wrap any other codec to make it work like that. If you're interested, I
can provide help doing that.

	Jean-Marc

> -SteveK
> 
> > Thank you all.
> > 
> > 
> >  
> > Regards,
> >  
> > Danny Chan
> > 
> > -----Original Message-----
> > From: speex-dev-bounces at xiph.org [mailto:speex-dev-bounces at xiph.org] On
> > Behalf Of Jean-Marc Valin
> > Sent: Tuesday, September 07, 2004 11:32 PM
> > To: Steve Kann
> > Cc: speex
> > Subject: Re: [Speex-dev] Jitter buffer
> > 
> > On mar, 2004-09-07 at 09:48 -0400, Steve Kann wrote:
> >   
> > > It's only 300 lines of C, so it shouldn't take very long for you to 
> > > study it --  it's not part of the codec proper.   I haven't used it,
> > > but 
> > > the advantage would be that (I believe) it supports interpolation of 
> > > lost frames, which your jitter buffer may not support.
> > >     
> > 
> > The interpolation of lost frames (PLC) is actually done within the
> > codec, so the jitter buffer just needs to ask for it. Another thing that
> > this jitter buffer supports (though I've never tested it seriously) is
> > support for multiple frames per packet. 
> > 
> > 	Jean-Marc
> > 
> > 
> > _______________________________________________
> > Speex-dev mailing list
> > Speex-dev at xiph.org
> > http://lists.xiph.org/mailman/listinfo/speex-dev
> > 
> > 
> >   




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