Re: [Iaxclient-devel] speex echo cancellation tested?

[Matthew C. <mc...@no...>]

On Mon, 2008-04-28 at 23:40 -0400, Peter Grayson wrote:

> >  Okay, I've found the source of the problem.  In audio_portaudio.c, the
> >  framesPerBuffer parameter in calls to Pa_OpenStream() was changed from
> >  paFramesPerBufferUnspecified to SAMPLES_PER_FRAME.  When I changed it
> >  back to the old value, audio sounds okay.  For whatever reason, the new
> >  value causes very choppy audio playback in SuSE Linux.
> 
> Ah ha. I believe it.
> 
> >  I suspect that we will need the fixed value of SAMPLES_PER_FRAME in
> >  order for echo cancellation to work, though, huh?  :-)
> 
> I think given the way the echo cancellation is currently implemented
> that yes, this is true. However, I think a different echo cancellation
> implementation that avoids doing sketchy things like fixing the
> samples (frames) per buffer to inappropriate values is certainly
> possible. I wish I had the bandwidth to address this right now, but I
> do not. Maybe someone else out there would like to take a cut at this
> one?
> 
> Pete

Good news:  For some reason, playback sounds fine with the fixed samples
per buffer when using the ALSA version of PortAudio.  The problems with
using the fixed samples per buffer appears to be limited to PortAudio
OSS.

This is all very strange.  The reason I started using OSS instead of
ALSA was because both iaxclient (using the old
paFramesPerBufferUnspecified parameter) and the PortAudio test programs
had choppy playback when using ALSA!  :-)

Next... testing echo cancellation!

-Matt