[Asterisk-Users] How "expensive" are the different codecs? (Regarding CPU time)

[Steve Underwood]

Michael Vogel wrote:

> Hi!
>
> The encoding, decoding and recoding cost cpu time, that's sure. But 
> does this time differs much depending on the used codec?
>
> Is - for example - a G729 faster than a GSM codec?
>
> Bye!
>
> Michael

They vary a lot. G.729 is pretty slow. iLBC and speex in the same 
ballpark. G.723.1 even slower. GSM 06.10 is reasonably fast.

Encode usually takes a low longer than decode - maybe 3 to 6 times, 
depending in the codec. One encode + one decode of G.723.1 is nearly 
20MIPs on a DSP chip. Multiply that by maybe 5 or 6 for MIPs on a 
Pentium. G.729 is maybe 11 DSP MIPs.

Regards,
Steve