[FFmpeg-cvslog] error concealment: check last pictures motion_val before using it.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Thu May 12 03:03:08 2011 +0200| [b8a4b0152a3a697e03fd28458098a514fcdee5d3] | committer: Michael Niedermayer

error concealment: check last pictures motion_val before using it.

Fixes NULL pointer dereference.
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b8a4b0152a3a697e03fd28458098a514fcdee5d3
---

 libavcodec/error_resilience.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/libavcodec/error_resilience.c b/libavcodec/error_resilience.c
index dac5559..c9231e2 100644
--- a/libavcodec/error_resilience.c
+++ b/libavcodec/error_resilience.c
@@ -381,7 +381,7 @@ static void guess_mv(MpegEncContext *s){
         fixed[mb_xy]= f;
         if(f==MV_FROZEN)
             num_avail++;
-        else if(s->last_picture.data[0]){
+        else if(s->last_picture.data[0] && s->last_picture.motion_val[0]){
             const int mb_y= mb_xy / s->mb_stride;
             const int mb_x= mb_xy % s->mb_stride;
             const int mot_index= (mb_x + mb_y*mot_stride) * mot_step;