[FFmpeg-cvslog] libavcodec/vp8: Do not compute line pointers per pixel in fade()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Jun 24 02:50:16 2018 +0200| [115b7c96e9e8823e5c8a8bc2137be8e2038befcd] | committer: Michael Niedermayer

libavcodec/vp8: Do not compute line pointers per pixel in fade()

72->60 seconds
Testcase: 8680/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VP7_fuzzer-5861504418054144

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=115b7c96e9e8823e5c8a8bc2137be8e2038befcd
---

 libavcodec/vp8.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
index 62b9f8bc2d..3adfeac3d9 100644
--- a/libavcodec/vp8.c
+++ b/libavcodec/vp8.c
@@ -492,9 +492,11 @@ static void fade(uint8_t *dst, ptrdiff_t dst_linesize,
 {
     int i, j;
     for (j = 0; j < height; j++) {
+        const uint8_t *src2 = src + j * src_linesize;
+        uint8_t *dst2 = dst + j * dst_linesize;
         for (i = 0; i < width; i++) {
-            uint8_t y = src[j * src_linesize + i];
-            dst[j * dst_linesize + i] = av_clip_uint8(y + ((y * beta) >> 8) + alpha);
+            uint8_t y = src2[i];
+            dst2[i] = av_clip_uint8(y + ((y * beta) >> 8) + alpha);
         }
     }
 }