1 files changed, 7 insertions, 2 deletions
diff --git a/contrib/ffmpeg/libavcodec/error_resilience.c b/contrib/ffmpeg/libavcodec/error_resilience.c
index 0923721ee..175ccf73a 100644
--- a/contrib/ffmpeg/libavcodec/error_resilience.c
+++ b/contrib/ffmpeg/libavcodec/error_resilience.c
@@ -612,12 +612,17 @@ void ff_er_frame_start(MpegEncContext *s){
  *               error of the same type occured
  */
 void ff_er_add_slice(MpegEncContext *s, int startx, int starty, int endx, int endy, int status){
-    const int start_i= clip(startx + starty * s->mb_width    , 0, s->mb_num-1);
-    const int end_i  = clip(endx   + endy   * s->mb_width    , 0, s->mb_num);
+    const int start_i= av_clip(startx + starty * s->mb_width    , 0, s->mb_num-1);
+    const int end_i  = av_clip(endx   + endy   * s->mb_width    , 0, s->mb_num);
     const int start_xy= s->mb_index2xy[start_i];
     const int end_xy  = s->mb_index2xy[end_i];
     int mask= -1;
 
+    if(start_i > end_i || start_xy > end_xy){
+        av_log(s->avctx, AV_LOG_ERROR, "internal error, slice end before start\n");
+        return;
+    }
+
     if(!s->error_resilience) return;
 
     mask &= ~VP_START;