[FFmpeg-cvslog] avcodec/h264_mvpred: Fix multiple runtime error: left shift of negative value

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Mar  3 04:39:06 2017 +0100| [ab998f4c7faf90d0e46b6ead38a1df1f6a31e2eb] | committer: Michael Niedermayer

avcodec/h264_mvpred: Fix multiple runtime error: left shift of negative value

Fixes: 710/clusterfuzz-testcase-5091051431788544

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ab998f4c7faf90d0e46b6ead38a1df1f6a31e2eb
---

 libavcodec/h264_mvpred.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/h264_mvpred.h b/libavcodec/h264_mvpred.h
index 24f250d..339cf62 100644
--- a/libavcodec/h264_mvpred.h
+++ b/libavcodec/h264_mvpred.h
@@ -248,7 +248,7 @@ static av_always_inline void pred_8x16_motion(const H264Context *const h,
             if (IS_INTERLACED(type)) {          \
                 refn >>= 1;                     \
                 AV_COPY32(mvbuf[idx], mvn);     \
-                mvbuf[idx][1] <<= 1;            \
+                mvbuf[idx][1] *= 2;             \
                 mvn = mvbuf[idx];               \
             }                                   \
         }                                       \