VP8: faster filter_level clip

(cherry picked from commit a1b227bb53)
14 years ago · c54ac7a8f2
parent 8cde1b7997
commit c54ac7a8f2
1 changed files with 4 additions and 1 deletions
--- 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);

    interior_limit = filter_level;
    if (s->filter.sharpness) {