mxf does not have timestamps

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@16947 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/mxfenc.c

@@ -1400,7 +1400,8 @@ AVOutputFormat mxf_muxer = {
     mxf_write_header,
     mxf_write_packet,
     mxf_write_footer,
-    0,
+    AVFMT_NOTIMESTAMPS,
     NULL,
     mxf_interleave,
+
 };