From c54ac7a8f252a03299c7686fb885c41ee9fc1233 Mon Sep 17 00:00:00 2001
From: Jason Garrett-Glaser <jason@x264.com>
Date: Thu, 3 Feb 2011 19:44:32 -0800
Subject: [PATCH] VP8: faster filter_level clip (cherry picked from commit
 a1b227bb533f173354795124e0b966277c251b56)

---
 libavcodec/vp8.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
index bcf623790c..1db57e49ac 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);
 
     interior_limit = filter_level;
     if (s->filter.sharpness) {