[FFmpeg-devel] Broken DNxHD encoder and ASM optimizations activation

[Matthieu Bouron]

On Thu, Sep 20, 2012 at 07:07:09PM +0200, Clément Bœsch wrote:
> On Thu, Sep 20, 2012 at 06:42:17PM +0200, Matthieu Bouron wrote:
> > Hello,
> > 
> > The DNxHD encoder is broken in its current state with 8bit profiles.
> > After some investigation, a regression was spotted at
> > d211547dddf9deeb34b7dda9cd80b86f3f5cd07a revision with asm optimizations
> > enabled or not.
> > 
> > This commit moves some code, which enables some optimisations, from
> > ff_MPV_commont_init_x86 to ff_MPV_encode_init_x86.
> > ff_MPV_common_init_x86 is used by ff_dct_common_init. So the encoders which
> > use ff_dct_common_init won't benefit anymore from the optimized
> > quantization functions.
> > It might be a good occasion to check if this kind of regression does not
> > affect other encoders.
> > 
> > Also, the C version of the quantization function ff_dct_quantize_c (which
> > is used for the DNxHD 8bit profiles) is broken and produces artefacts as in
> > the following sample:
> > http://samples.lolito.fr/DNXHD/test_dnxhd_120M_yuv422p.mxf
> > 
> 
> You mean http://samples.lolito.fr/DNXHD/test.png as input, right?
> 
Right, this file was used to generate the DNxHD/MXF one.

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