From 088ed4d636e3065bf4fc67ef11bfe8592bcd8c0e Mon Sep 17 00:00:00 2001
From: Jeff Downs <heydowns@borg.com>
Date: Wed, 5 Sep 2007 20:04:09 +0000
Subject: [PATCH] Avoid a crash when H264 MMC operation causes the short term
 reference list to be emptied. Patch by Jeff Downs: [heydowns borg com]

Originally committed as revision 10416 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/h264.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index a4d2a13391..49eaa378c1 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -3159,8 +3159,8 @@ static Picture * remove_short(H264Context *h, int frame_num){
             av_log(h->s.avctx, AV_LOG_DEBUG, "%d %d %p\n", i, pic->frame_num, pic);
         if(pic->frame_num == frame_num){
             h->short_ref[i]= NULL;
-            memmove(&h->short_ref[i], &h->short_ref[i+1], (h->short_ref_count - i - 1)*sizeof(Picture*));
-            h->short_ref_count--;
+            if (--h->short_ref_count)
+                memmove(&h->short_ref[i], &h->short_ref[i+1], (h->short_ref_count - i)*sizeof(Picture*));
             return pic;
         }
     }