[FFmpeg-devel] [PATCH] QCELP decoder

Michael Niedermayer michaelni
Sat Oct 11 18:26:39 CEST 2008

On Sat, Oct 11, 2008 at 12:30:48PM +0200, Benjamin Larsson wrote:
> Hi.
> > 
> > The patch using the reference code is at [2].
> > As a plan of action, I propose to work on the inclusion of this patch  
> > as a first
> > step, and then continue on working the SoC decoder
> > 
> > what do you think ?
> Well we removed the amr reference code support because of license
> issues, so I don't think we should add more code in. The best way to do
> this is to add working reference glue code to the SoC qcelp tree. 

i agree

> Then
> port the current decoder to fixed point. Then make sure the decoder is
> bit exact compared to the reference source. This would remove any doubt
> of compliance but it would be alot of work. There is lots of fixed point
> code available in in the g729 patches that are aimed for speech codecs.
> So are you up for all that work ? You could get svn commit access to the
>  qcelp soc tree if that would help out your work and the review process.

i think we should be aiming at a float+fixed point implementation
both have advantages. I do not think throwing the float away and replacing
it by fixed point is such a good idea. fixed point likely is slower on
modern cpus but then its very usefull for regression tests and fpu-less
Also bit exactness and sharing code between g729, amr and qcelp may become
tricky though of course both should be attepted where its possible, where its
not some compromise has to be found.

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Observe your enemies, for they first find out your faults. -- Antisthenes
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