[FFmpeg-devel] [PATCH] avcodec/fic: avoid 2 additions per idct row

[Michael Niedermayer]

On Wed, Apr 23, 2014 at 08:17:19PM +0100, Derek Buitenhuis wrote:
> On 4/23/2014 8:10 PM, Michael Niedermayer wrote:
> > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> > ---
> >  libavcodec/fic.c |   13 +++++++------
> >  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> I assume this passes FATE.

it does


> 
> Is there any measurable speedup?

before:
5225 decicycles in IDCT, 32756 runs, 12 skips

after:
5057 decicycles in IDCT, 32765 runs, 3 skips


> 
> 
> > -    for (i = 0; i < 8; i++) {
> > -        fic_idct(ptr, 8, 13);
> > +    fic_idct(ptr++, 8, 13, (1<<12) + (1<<17));
> 
> fic_idct(ptr++, 8, 13, (1 << 12) + (1 << 17));
> 
> > +    for (i = 1; i < 8; i++) {
> > +        fic_idct(ptr, 8, 13, 1<<12);
> 
> fic_idct(ptr, 8, 13, 1 << 12);

changed

> 
> Otherwise, OK.

commited

thanks

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

During times of universal deceit, telling the truth becomes a
revolutionary act. -- George Orwell
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