[Speex-dev] Question from XM Radio

Steve Kann stevek at stevek.com
Mon Nov 28 14:46:10 PST 2005

Carr, Terrance wrote:

>Thanks Jim, that's understood.  When I say AMBE isn't working well, I
>only mean from the audience acceptance point of view.  Technically it is
>fine.  It is exactly doing the job we had expected.
>It's the long standing wish that everyone wants... More for less.  We
>are just seeking a bit of magic that just may not be there.  Ideally
>finding a codec that can perform tollerably/intelligibly at 2-4Kbps.
>And still perform quite well for complex speech at 10-12kbps.
>Just keeping my eyes (ears) out for something that I have never
>considered before.
>I really appreaciate the time you've taken to reply, Thanks.

I'm not sure if your equipment can handle variable-bit-rates, or if you 
have enough such channels to make use of it (or enough buffering, etc), 
but speex' variable bit-rate modes may be something useful for you as 
well. (and yes, I've heard the AMBE broadcasts you refer to, and they, 
err, do sound only slightly better than LPC10, although, if I recall 
correctly, it did sound like you had more than 8khz sampling in there).

We use speex with 8kbps in the ABR mode (where it will use 8kbps 
average, but can use more/less depending on speech complexity), and find 
that it is very good.

Good luck on your search. It sure would be cool, though, to know speex 
was in my next XM radio :)


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