Sound quality in calls.

Al Johnson openmoko at
Thu Sep 18 11:50:03 CEST 2008

On Thursday 18 September 2008, Armin ranjbar wrote:
> On Wed, 17 Sep 2008 21:29:53 +0100
> Al Johnson <openmoko at> wrote:
> I can understand your point now , this is my problem :
> VERY bad sound quality using Headset under Qtopia and
> openmoko mediaplayer , lots of Strange noises , echoes , and totally
> unlistenable quality .
> you know what is strange about it ? using Mplayer sound quality is Nearly
> perfect ( except for lack of bass , which is not very important ) , any
> idea ?!
> is this the issue with pulse audio and or soundserver ?

Thanks. This sort of question is _much_ more likely to get a useful answer.

I've not looked into this directly, but IIRC there were reports of pulseaudio 
doing sample rate conversion on almost everything that was played, munching 
CPU in the process and not necessarily leaving enough for smooth decode of 
the media file. The media player in 2007.2 was apparently affected by this, 
but if patched to use alsa directly it was fine. I can't verify this as I had 
gstreamer errors with the mp3 I tried it with. I think pulseaudio has been 
dropped from 2008.8 and FSO because of this. I don't know what the situation 
is with qtopia, but if you run top while playing a file you should see if 
anything's  hogging CPU. I suggest you search the list archives for the 
original reports on this issue as they probably contain details I've 
forgotten or got wrong ;-)

mplayer by default  plays directly through alsa so isn't affected by the sound 
server issues. That you say sound is nearly perfect in this case shows the 
hardware limitation isn't really the issue.

I haven't looked closely at the whole media playback issue so I don't know 
what the best solution is. If you're lucky someone who does might read this, 
but you may be better off reposting with a more appropriate subject line.

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