[Speex-dev] Question from XM Radio

Carr, Terrance
Sun, 27 Nov 2005 14:11:09 -0000

Thanks for the reply.  We are currently using AMBE (4Kbps) for our
Traffic/Weather Channels.  If you have ever had a chance to hear the service,
you will know that AMBE does not do us well.

I understand that 2Kbps is low quality, but any poorer than AMBE?

If can get a decent quality for other low bandwidth talk channels, such as about
10-16Kbps and have it sound rather clean, then I would be gaining a bit of
growth in the areas I'm seeking.

None of this would be Music, understand.  Music needs it's bandwidth... just
voice only channels like:

- Emergency Announcements
- Barkers (This channel is not yet scheduled for Air
- Traffic/Weather
- ...etc

Thanks again for the reply.

____________________________________________________________________________________________
Terry Carr
Manager, Broadcast Applications
XM SATELLITE RADIO
1500 Eckington Place, NE (Flr-2, Ops Mgt)
Washington, DC 20002
Phone: (202) 380-4081 - Fax: (202) 380-4768

________________________________

From: Jean-Marc Valin [mailto:Jean-Marc.Valin@USherbrooke.ca]
Sent: Sun 11/27/2005 4:55 PM
To: Carr, Terrance
Cc: speex-dev@xiph.org
Subject: Re: [Speex-dev] Question from XM Radio



You can try the Ogg DirectShow filter to get Windows support for Speex:
http://www.illiminable.com/ogg/

> My goal is to find a promising codec for 2Kbps.

You should be aware that the 2 kbps mode has quite poor quality in
Speex, a bit similar to the LPC10 vocoder.

> - Has there been any successful satellite streaming projects using
> Speex?

Not that I know of.

> - Has there been any projects having a decoder embedded in an IC

Not that I know of.

> - If none of the above, what type of processing power for real-time
> Encoding/Decoding are we talking.  Does anyone have real-time
> encoding/decoding software yet?

The source code can be compiled as fixed-point and I would think the
complexity is somewhere in the 5-10 MIPS range for encode+decode
(decoding is cheaper than encoding).

        Jean-Marc




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