[FFmpeg-devel] [PATCH] Move lpc utility code from flacenc.c to?lpc.{c|h}

[Michael Niedermayer]

On Fri, Aug 15, 2008 at 04:56:44PM +0530, Jai Menon wrote:
> Hi,
> 
> On Friday 15 Aug 2008 4:44:35 pm Michael Niedermayer wrote:
> > On Fri, Aug 15, 2008 at 03:07:12PM +0530, Jai Menon wrote:
> > > Hi,
> > >
> > > On Friday 15 Aug 2008 2:58:15 pm Ramiro Polla wrote:
> > > > Hi,
> > > >
> > > > On Fri, Aug 15, 2008 at 3:14 AM, Jai Menon <realityman at gmx.net> wrote:
> > > > > Attached patch moves a few functions from the flac encoder so that it
> > > > > can be shared by the alac encoder.
> > > >
> > > > For MLP I used the entire lpc_calc_coefs(). Is that not ok for alac?
> > >
> > > No, currently the order estimation does not require such extensive code.
> > > It doesn't really help with compression or speed. A simpler approach is
> > > used instead.
> >
> > please also use lpc_calc_coefs()
> >
> 
> Its just that for the first iteration of the encoder which I hope will end up 
> in FFmpeg-svn, I'm planning to keep the order selection simple. The 
> approach(in so-svn) gives pretty good compression (better than dbpoweramp 
> always, slightly lesser than itunes). We just need to quantize either 4th or 
> 6th order lpc coeffs. If I use the stock lpc_calc_coeffs, I'll have to make 
> use of the EST method which will quantize all coeffs upto 6th order. This 
> ends up being suboptimal. I didn't reuse lpc_calc_coefs because the speed 
> tradeoff is significant.

add a new ORDER_METHOD, its not unlikely that flac will benefit as well.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because
microsoft did it is even more stupid. If everything ms did were stupid they
would be bankrupt already.
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