Re: [Linphone-users] Run codecs in 8 bit

[Simon Morlat]

Le mercredi 11 octobre 2006 09:53, Micha Nelissen a écrit :
> Simon Morlat wrote:
> > 8bit pcm does not give a good quality. Perhaps it's 8bit g711 (pcmu
> > or pcma).
> > In mediastreamer2/src
> > you need to modify one of the soundcard reader/writer (alsa.c or
> > oss.c, depending on whether you use alsa or old oss drivers), and the
> > connection of graph done in audiostream.c to insert the proper
> > decoder to pcm 16 bit if the samples returned by the audio device are
> > pcmu or pcma.
>
> Do the 8<->16bit conversion codecs already exist, or do I need to write
> them myself ?

If your hardware gives alaw(=pcma) or ulaw(=pcmu) 8 bit samples, then you can 
directly use the decoder in alaw.c and ulaw.c.
If it's not the case, you can just bitshift, but quality will be poor.

Simomn
>
> (Would bitshifting be enough?)
>
> Regards,
>
> Micha
>
>
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