[speex-dev] Some questions

[Devendra Jalihal]

GSM 6.10 was standardized way back in 1988 when we didn't have powerful
(high "MIPS") DSPs. Basically, the handsets (mobiles) need to have some
processor in order to encode/decode speech. GSM 6.10 is an example of a
low-complexity closed-loop processing of speech that compromises on
quality. It needs just about 2 MIPS. A fair comparison in complexity and
quality is to compare speex with G.723.1 (5.3 kbps), G.729 and other
patented CELP coders. These typically take 16-20 MIPS indicating their
high computational complexity. 
-Devendra Jalihal

<p>On Tue, 23 Sep 2003, Jonas Tärnström wrote:

> Hi,
> I might have written to this mailing list previously about this but I've
> been experiencing some mailing problems so I write this again.
> 
> First of all, thanks Jean-Marc Valin for your continued efforts on
> speex.
> I must say that I am very impressed with Speex and further more the
> innovative features recently added in 1.1.
> They have worked great for me. 
> 
> Question 1)
> What is the return value from speex_preprocess good for? It's called
> "vad" in the denoise sample. It seems always to be = 1.
> 
> Question 2)
> While comparing Speex with GSM 06.10. It struck me that Speex is pretty
> CPU intense compared to GSM 06.10. Are there any plans or (even)
> possibilities of optimizing Speex?
> 
> In my sample program for Win32 compiled with MSVS.NET. Speex loads about
> 7 % CPU in Narrow mode, compared to GSM 06.10 which loads approx. 0,5 to
> 1.0 %.
> I am not sure if the CPU usage is reliable in any way as a benchmark.
> 
> 
> //Best Regards, Jonas Tärnström, Sweden.
> 
> 
> 
> --- >8 ----
> List archives:  http://www.xiph.org/archives/
> Ogg project homepage: http://www.xiph.org/ogg/
> To unsubscribe from this list, send a message to 'speex-dev-request at xiph.org'
> containing only the word 'unsubscribe' in the body.  No subject is needed.
> Unsubscribe messages sent to the list will be ignored/filtered.
> 

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'speex-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.