[Asterisk-Users] How to config speex?

[Steve Kann]

Roman Zhovtulya wrote:

> As far as I know speex is an adaptive codec, i.e. it will 
> automatically adjust to the conditions and provide the best quality 
> possible.
> Therefore, there should be no need to configure that manually.
>  
> Could anyone correct me if I'm wrong?

It can do this (this is Variable BitRate, or VBR mode).

It also has CBR (constant bitrate), and ABR (average bitrate) modes.

These are controlled in asterisk by codecs.conf, but I think that 
feature may not be present in 1.0; only in CVS-Head.

>  
> On the other hand, I was thinking about getting my Asterisk and 
> SJPhone run with Speex.
>  
> Does anyone have experience?

Yes, but not with SJPhone.

> What's the quality boost compared to iLBC?

Since Speex can use different bitrates/quality settings, it can scale 
from very low bitrates (where it sounds like LPC-10), to higher 
bitrates, where it's indistingishable from uncompressed (i.e. uLaw) audio.

bit for bit, it's close, or slightly better than iLBC.  My experience is 
that using 8kbps ABR mode gives very good quality.

> Ist is difficult to install?

As long as you have libspeex installed when you build asterisk, it's there.

>  
> Can I install speex on win2000/XP and use it from any softphone?
> How do I add speex to SJPhone's list of codecs?


It's included with most iaxclient-based softphones.  There endeth my 
Win32 knowledge :)

-SteveK