add a check before find_frame_end call

Patch by Limin Wang % lance P lmwang A gmail P com %
Original thread:
date: 04/09/2007 03:54 PM
subject: [Ffmpeg-devel] [PATCH] fix segment fault in h264_parse if buf_size is zero

Originally committed as revision 8714 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264.c

@@ -8059,7 +8059,8 @@ static int h264_parse(AVCodecParserContext *s,
             return buf_size;
         }
 
-        if(next<0){
+        if(next<0 && next != END_NOT_FOUND){
+            assert(pc->last_index + next >= 0 );
             find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
         }
     }