[FFmpeg-devel] [PATCH] VP8: faster filter_level clip

[Jason Garrett-Glaser]

2011/2/4 M?ns Rullg?rd <mans at mansr.com>:
> Jason Garrett-Glaser <jason at x264.com> writes:
>
>> ---
>> ?libavcodec/vp8.c | ? ?5 ++++-
>> ?1 files changed, 4 insertions(+), 1 deletions(-)
>>
>> diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
>> index bcf6237..1db57e4 100644
>> --- a/libavcodec/vp8.c
>> +++ b/libavcodec/vp8.c
>> @@ -1480,7 +1480,10 @@ static av_always_inline void filter_level_for_mb(VP8Context *s, VP8Macroblock *m
>> ? ? ? ? ?filter_level += s->lf_delta.ref[mb->ref_frame];
>> ? ? ? ? ?filter_level += s->lf_delta.mode[mb->mode];
>> ? ? ?}
>> - ? ?filter_level = av_clip(filter_level, 0, 63);
>> +
>> +/* Like av_clip for inputs 0 and max, where max is equal to (2^n-1) */
>> +#define POW2CLIP(x,max) (((x) & ~max) ? (-(x))>>31 & max : (x));
>> + ? ?filter_level = POW2CLIP(filter_level, 63);
>
> ARM has an instruction for that. ?We should make sure it gets used.

Want to add a libavutil macro for it somewhere?  Patches welcome.

Jason