[FFmpeg-cvslog] avcodec/h264_mvpred: Fix runtime error: left shift of negative value -1

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Wed Mar  8 21:53:15 2017 +0100| [222c9f031de3315af62be6d7a99c71105e516088] | committer: Michael Niedermayer

avcodec/h264_mvpred: Fix runtime error: left shift of negative value -1

Fixes: 734/clusterfuzz-testcase-4821293192970240

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=222c9f031de3315af62be6d7a99c71105e516088
---

 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 339cf62..bf395e3 100644
--- a/libavcodec/h264_mvpred.h
+++ b/libavcodec/h264_mvpred.h
@@ -68,7 +68,7 @@ static av_always_inline int fetch_diagonal_mv(const H264Context *h, H264SliceCon
             }
             if (MB_FIELD(sl) && !IS_INTERLACED(sl->left_type[0])) {
                 // left shift will turn LIST_NOT_USED into PART_NOT_AVAILABLE, but that's OK.
-                SET_DIAG_MV(/ 2, << 1, sl->left_mb_xy[i >= 36], ((i >> 2)) & 3);
+                SET_DIAG_MV(/ 2, *2, sl->left_mb_xy[i >= 36], ((i >> 2)) & 3);
             }
         }
 #undef SET_DIAG_MV