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

George Ou george_ou at lanarchitect.net
Thu Aug 17 22:48:06 PDT 2006

Can we get a response from Verisilicon on this?  We spoke at the VoIP
developer conference and you seemed to indicate that Speex was too difficult
for you guys to implement in your embedded products.  Mr. Valin would like
to know specifically what your criteria is to run on your silicon.  He needs
to know the following.

What is the maximum code size that you can use?
What is the maximum data working set you can use?
What is the maximum DSP MHz you can spare?

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


-----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.


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