Only store timestamps when there are timestamps.

Originally committed as revision 13627 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/parser.c

@@ -134,12 +134,14 @@ int av_parser_parse(AVCodecParserContext *s,
         buf = dummy_buf;
     } else {
         /* add a new packet descriptor */
+        if(pts != AV_NOPTS_VALUE || dts != AV_NOPTS_VALUE){
         i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
         s->cur_frame_start_index = i;
         s->cur_frame_offset[i] = s->cur_offset;
         s->cur_frame_end[i] = s->cur_offset + buf_size;
         s->cur_frame_pts[i] = pts;
         s->cur_frame_dts[i] = dts;
+        }
     }
 
     if (s->fetch_timestamp){