[Speex-dev] Speex and Builder

Jean-Marc Valin Jean-Marc.Valin at USherbrooke.ca
Wed Sep 21 02:59:18 PDT 2005

> 1) May I know how Speex compared with GIPS codec?  It seems that Google,
> Yahoo, and Skype are licensing from GIPS.  Are there any good benchmarking
> or fair comparisons?

I think these two emails sum up my opinion about Speex vs. iLBC:

> 2) In particular, how is the jitter buffer control for Speex in response to
> intermitent poor connection hiccups?  Is it robust enough to smooth out lost
> packets (error concealment) and quick enough to recover the live
> conversation smoothly once the packets received are back to normalcy?

There is packet loss concealment in Speex even without using the jitter
buffer (no, error concealment wasn't invented by GIPS). As for the
jitter buffer itself, it's adaptive, so it just keeps the lowest
possible delay that doesn't cause losses.

> 3) Has anyone used Speex for live VoIP application?  Any good references or
> examples to start with? 

I've written a demo application for Linux that uses wideband, echo
cancellation, denoising and the jitter buffer. I'll post it soon.

> 4) Since we are focusing on the user application development, may I know
> what is the highest-level API for Speex that a developer can use such that
> all lower-level issues related to buffering, error concealment, codec, etc.
> are automatically taken care of?

There's only the Speex API, but I think it's simple enough that you
don't need a higher level API (at least not for VoIP).


Jean-Marc Valin <Jean-Marc.Valin at USherbrooke.ca>
Université de Sherbrooke

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