[Speex-dev] Delays estimation in Speex algorithms

Alexander Chemeris Alexander.Chemeris at sipez.com
Mon Jun 29 10:57:16 PDT 2009


I want to do a careful measure of mic-to-net and net-to-spkr delays
in sip media engine and to make it really precise I need to know
delays, introduced by Speex algorithms. In particular, I'm interested
in delays of:
1) encoder in NB, WB and UWB modes,
2) decoder (I guess it should be 0?)
3) resampler. I think it varies depending on input rate to output rate
ratio. Any generic formula or at least values for specific ratios available?
4) AEC
5) preprocessor

If anyone knows delays added by at least some of these algorithms,
please, share this knowledge. I believe that this is worth doing and
I promise to compile a patch to Speex documentation with obtained
values and formulas. In VoIP we fight for every ms of latency, so lets
make people more aware of the actual values.

Alexander Chemeris.

SIP VoIP, IM and Presence Consulting
tel: +1 (617) 273-4000

More information about the Speex-dev mailing list