From 69409ccb801939f4b09f16946a236d10e18f7005 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Thu, 9 Apr 2009 20:13:35 +0000
Subject: [PATCH] Skip non intra frames that have no reference frames.

Originally committed as revision 18395 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/snow.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavcodec/snow.c b/libavcodec/snow.c
index 501b60dde4..ffdf1ffd02 100644
--- a/libavcodec/snow.c
+++ b/libavcodec/snow.c
@@ -4145,6 +4145,10 @@ static int frame_start(SnowContext *s){
             if(i && s->last_picture[i-1].key_frame)
                 break;
         s->ref_frames= i;
+        if(s->ref_frames==0){
+            av_log(s->avctx,AV_LOG_ERROR, "No reference frames\n");
+            return -1;
+        }
     }
 
     s->current_picture.reference= 1;
@@ -4520,7 +4524,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPac
 
     alloc_blocks(s);
 
-    frame_start(s);
+    if(frame_start(s) < 0)
+        return -1;
     //keyframe flag duplication mess FIXME
     if(avctx->debug&FF_DEBUG_PICT_INFO)
         av_log(avctx, AV_LOG_ERROR, "keyframe:%d qlog:%d\n", s->keyframe, s->qlog);