all asf files i have have the 2 redundant duration fields differ by the preroll time so lets set them up like that too

Originally committed as revision 8239 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/asf-enc.c

@@ -309,7 +309,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size, int64_t data
     put_le64(pb, unix_to_file_time(file_time));
     put_le64(pb, asf->nb_packets); /* number of packets */
     put_le64(pb, duration); /* end time stamp (in 100ns units) */
-    put_le64(pb, duration); /* duration (in 100ns units) */
+    put_le64(pb, asf->duration); /* duration (in 100ns units) */
     put_le64(pb, preroll_time); /* start time stamp */
     put_le32(pb, asf->is_streamed ? 3 : 2); /* ??? */
     put_le32(pb, asf->packet_size); /* packet size */

tests/libav.regression.ref

@@ -2,7 +2,7 @@ ffmpeg regression test
 8a0536ccfe36f4fff408b3327d33e1dd *./data/b-libav.avi
 340344 ./data/b-libav.avi
 ./data/b-libav.avi CRC=0x400c29e9
-aa0016b3bc33b8ba3124f05bdf6753f7 *./data/b-libav.asf
+a41bf92d0756cec87288583175f6b5a9 *./data/b-libav.asf
 339775 ./data/b-libav.asf
 ./data/b-libav.asf CRC=0x74113749
 1ad618e9fd318eb3483270cf9b9b3f43 *./data/b-libav.rm