[asterisk-dev] Asterisk transcoding with Speex

SteveK stevek at stevek.com
Fri Feb 17 17:43:41 MST 2006

On Feb 16, 2006, at 12:30 PM, Jonathan Blais wrote:

> Hi there,
> Is it very costly on server side, when Asterisk is mixing two kinds  
> of Speex frames, the first one is encoded with quality 1 and the  
> other one with quality 10 ?
I'm not sure what you mean by mixing here..

Speex decode is pretty cheap;  I imagine that it makes some  
difference how it was encoded, but it's still an order of magnitude  
cheaper than encode.

Speex encode speeds depend greatly on the complexity and quality you  
use.  I generally use complexity 2, and use ABR to set the bitrate.

Also, if you compile your own speex libraries with SSE support,  
you'll get something like 25% improvement in speed as compared to  
vendor-supplied libraries.


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