From 0dfcc368188d9c8ffba79f2165521a43cde62ea0 Mon Sep 17 00:00:00 2001
From: Kostya Shishkov <kostya.shishkov@gmail.com>
Date: Sun, 7 Dec 2008 16:30:08 +0000
Subject: [PATCH] Do not attempt to decode RV30/40 B-frames without anchors.

This fixes issue 747.

Originally committed as revision 16031 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/rv34.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/rv34.c b/libavcodec/rv34.c
index 463594320c..6cf5869ab1 100644
--- a/libavcodec/rv34.c
+++ b/libavcodec/rv34.c
@@ -1406,6 +1406,8 @@ int ff_rv34_decode_frame(AVCodecContext *avctx,
             }else
                 r->si.end = si.start;
         }
+        if(!i && si.type == FF_B_TYPE && (!s->last_picture_ptr || !s->last_picture_ptr->data[0]))
+            return -1;
         last = rv34_decode_slice(r, r->si.end, buf + offset, size);
         s->mb_num_left = r->s.mb_x + r->s.mb_y*r->s.mb_width - r->si.start;
         if(last)