[FFmpeg-devel] [PATCH] ALAC Encoder

Michael Niedermayer michaelni
Thu Aug 21 16:16:57 CEST 2008

On Tue, Aug 19, 2008 at 10:41:17PM +0530, Jai Menon wrote:
> Hi,
> On Tuesday 19 Aug 2008 9:45:41 pm Michael Niedermayer wrote:
> > patch ok
> >
> And applied...

> Thanks for the reviews!

no problem

anyway, some further ideas:
* as ALAC dynamically adapts the LPC coeffs its not optimal to calculate
  the best ones for the whole block with equal weighting for each sample.
  for example if i simply just calculate them based on the first 1/4 of
  the block, compression (and speed) improves.
  That surely is an area that should be investigated, maybe using some
  asymetric and at the right side exponentially decaying window instead
  of the welch window ...
* regression tests, ive totally forgotten about them, but each new encoder
  should be added to them, i think alac hasnt been yet ...
* more decorrelation types could be tried at higher compression_level
* rice_modifier
  ive missed this parameter totally because it is not used in the encoder
  but instead just replaced by a litteral number where its used.
  This should also be fine tuned for each frame

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
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