[FFmpeg-devel] [PATCH] MMX implementation of VC-1 inverse transforms

Balatoni Denes dbalatoni
Mon Jan 14 22:18:33 CET 2008


Monday 14 January 2008 20:50-kor Ivan Kalvachev ezt ?rta:
> On Jan 14, 2008 1:05 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Sun, Jan 13, 2008 at 05:10:30PM +0100, Christophe GISQUET wrote:

> - Have you seen how other IDCT optimizations work? I may be wrong but
> vc1 transformations look like IDCT with quite simplified (smaller)
> coefficients.

Figuring out how the other IDCTs work is not so simple task as you make it 
look like. For example the simple_idct is the fastest and most accurate, but 
it is quite involved (some crazy reordering imho), I for one couldn't figure 
out how it works during the time I spent on it. The other IDCTs are simpler, 
but there is not "black magic" in them either.


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