[Speex-dev] RE: Speex-dev Digest, Vol 27, Issue 18

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Thu Aug 17 22:59:06 PDT 2006

> I would love to see Speex working in embedded products.  Mr. Valin, do you
> know of any examples of Speex working in embedded gear?

Yes. We got Speex to run on DSPs like the Blackfin, the TI C5x and C6x
and some ARM chips. There are lots of places where memory and CPU can be
reduced by changing options (Speex is designed to be very adaptable).
Also, the next release (probably next week) will cut memory use by more
than half on embedded devices.


> George
> -----Original Message-----
> From: Jean-Marc Valin [mailto:jean-marc.valin at usherbrooke.ca] 
> Sent: Thursday, August 17, 2006 10:41 PM
> To: George Ou
> Cc: speex-dev at xiph.org
> Subject: Re: [Speex-dev] RE: Speex-dev Digest, Vol 27, Issue 18
>> I cover some VoIP issues.  I was at VoIP developer conference and 
>> asked an embedded manufacturer (we're talking Wi-Fi phones) about 
>> supporting Speex in their embedded products.  He said that Speex was 
>> good but it's too many things to too many people and that he couldn't 
>> supported it in his embedded products for the following reasons.
> Speex has lots of features but I'm not forcing anyone to use them all.
>> *	Code size must be extremely small
> Please define "extremely small", that's very relative.
>> *	Data working set must also be extremely small
> Please define "data working set" and "extremely small".
>> *	Use very few MHz of a DSP
> Please "very few" :-)
>> *	Needs packet loss concealment (I believe Speex has this)
> Yes, Speex has that.
>> His recommendation was that because packet overhead alone was in the 
>> 24 kbps range, there is nothing wrong with having a 16 KHz wideband 
>> stream that uses
>> 24 kbps so long as it meets the above embedded criteria.  He said that 
>> the VBR support and ultra low bandwidth capability wasn't really useful.
> Wideband Speex is actually in this range of bit-rate. I usually recommend
> between 20 and 28 kbps). And I agree that VBR and ultra low bandwidth are
> useless for that application.
>> What we need is something that would meet the lowest common 
>> denominator in hardware yet deliver a wideband stream in less than 24 kbps
> for the payload.
>> Can someone comment on this?
> You've pretty much described the main application I had in mind when doing
> Speex. I really don't see what the problem is.
> 	Jean-Marc

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