Do not skip frames until the first keyframe when stream copying but

no starttime is set.
Fixes at least -vcodec copy with VS2k5DebugDemo-01-partial.avi.

Originally committed as revision 16159 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -1353,7 +1353,7 @@ static int output_packet(AVInputStream *ist, int ist_index,
                         AVPacket opkt;
                         av_init_packet(&opkt);
 
-                        if (!ost->frame_number && !(pkt->flags & PKT_FLAG_KEY))
+                        if ((!ost->frame_number && !(pkt->flags & PKT_FLAG_KEY)) && start_time)
                             continue;
 
                         /* no reencoding needed : output the packet directly */