[Speex-dev] low data rate codecs

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Fri May 15 04:19:21 PDT 2009

Pandya, Julee a écrit :
> I’ve been testing out the speex narrowband codec at low data rates
> (using linphone and Counterpath’s Eyebeam).  I’m finding that at data
> rates of ~25 kbps, the quality of the voice call is very poor. 

If the sound quality is poor at those rates, then it's a bug somewhere
(interoperability problem, losing packets, ...)?

 I know
> speex is supposed to work at much lower data rates (~2 kbps).  Has
> anyone verified that speex will produce reasonable quality at low data
> rates?  Are there any existing VoIP software clients that will utilize
> speex at low data rates?

There's no point in using 2 kbps for VoIP because just sending 20 ms
costs you 16 kbps in headers (IP/UDP/RTP) alone.


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