[FFmpeg-devel] pre discussion around Blackfin dct_quantize_bfin routine

Michael Niedermayer michaelni
Wed Jun 13 01:27:24 CEST 2007


On Tue, Jun 12, 2007 at 02:52:29PM +0300, Siarhei Siamashka wrote:
> On 6/12/07, Michael Niedermayer <michaelni at gmx.at> wrote:
> > Hi
> >
> > On Tue, Jun 12, 2007 at 05:49:19AM -0400, Marc Hoffman wrote:
> > > Does these allow me to ignore the DCT permutation?
> >
> > no it would still break if the user selected the other integer idct
> Is it possible to add a configure option to be able to compile ffmpeg
> only with IDCT that do not need permutation (and do not allow the user
> to select other idct)? At least it would eliminate table lookups in
> many places (replace table lookups with a macro which expands either
> to table lookup or the value itself). The point is that ARM devices
> are heavily CPU limited and ARMv5TE optimized IDCT does not use
> permutation. Blackfin powered devices may be CPU limited too (Marc can
> probably privide more information about blackfin performance). I'll
> try to do some benchmarks on ARM and post some results later.

if(idct_permutation_type != FF_NO_IDCT_PERM)

is fast, there is no need to randomly hack up the code

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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