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

Derek Buitenhuis derek.buitenhuis at gmail.com
Wed Apr 23 21:17:19 CEST 2014


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.

Is there any measurable speedup?


> -    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);

Otherwise, OK.

- Derek


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