[mythtv] Audio out of sync when transcoding dvb recordings

[Lee Mitchell]

Hi all,

  I'm running cvs from just before xmas, and everything works really 
well except for when I set myth to transcode recordings from my Nova-T 
DVB-T card.

The problem is that the audio starts off out of sync with the video, and 
remains that way all the way through the transcoded file. It doesn't get 
any more, or less out of sync, it just remains  about a second out of 
sync all the way through.

The original recordings all play perfectly.

If however, I use nuvexport to transcode the recording, everything works 
as it should. I get the following output, and the audio and video start, 
and remain in sync throughout the recording.


<--- output from nuvexport --->


What would you like to do with your recording?

          Show:  The Simpsons
       Episode:  Untitled
       Airtime:  1/7, 6:00 PM

   1. Export to SVCD
   2. Extract .nuv and .sql
   3. Export DivX
   4. Export WMV
   5. Export to VCD
   6. Export to DVD
   7. Export OGM (CLI support) (disabled)
   8. Export to MP3
   9. Transcode export to XviD
  10. Transcode export to VCD
  11. Transcode export to SVCD

   r. Return to episode menu
   q. Quit

Choose a function:  4
Where would you like to export the files to? [.]
Output filename?  [The Simpsons.wmv]
Enable Myth cutlist? [No]
Audio bitrate? [64]
Video bitrate? [256] 512
Horizontal resolution? [320] 720
Vertical resolution? [240] 576
[tcprobe] MPEG packetized elementary stream (PES)
2005-01-08 23:05:14.720 Transcoding from 
/mnt/video/1024_20050107180000_20050107183000.nuv to 
/mnt/video/1024_20050107180000_20050107183000.nuv.tmp
2005-01-08 23:05:14.799 Initializing audio parms from stream #0.
2005-01-08 23:05:15.166 Created video fifo: /tmp/fifodir.3118/vidout
2005-01-08 23:05:15.170 Created audio fifo: /tmp/fifodir.3118/audout
2005-01-08 23:05:15.174 Video 704x576 at 25fps Audio rate: 48000
2005-01-08 23:05:15.175 Created fifos. Waiting for connection.
Waiting for mythtranscode to set up the fifos.
2005-01-08 23:05:15.264 Audio is 485ms ahead of video at # 1
2005-01-08 23:05:15.322 Audio is 445ms ahead of video at # 3
ffmpeg version 0.4.9-pre1, build 4718, Copyright (c) 2000-2004 Fabrice 
Bellard
   built on Nov 28 2004 15:03:50, gcc: 3.3.2 20031218 (Gentoo Linux 
3.3.2-r5, propolice-3.3-7)
Input #0, s16le, from '/tmp/fifodir.3118/audout':
   Duration: N/A, bitrate: N/A
   Stream #0.0: Audio: pcm_s16le, 48000 Hz, stereo, 1536 kb/s
Input #1, rawvideo, from '/tmp/fifodir.3118/vidout':
   Duration: N/A, bitrate: N/A
   Stream #1.0: Video: rawvideo, yuv420p, 704x576, 25.00 fps
Output #0, asf, to 'The Simpsons.wmv':
   Stream #0.0: Video: msmpeg4, 720x576, 25.00 fps, q=2-31, 512 kb/s
   Stream #0.1: Audio: mp3, 48000 Hz, stereo, 64 kb/s
Stream mapping:
   Stream #1.0 -> #0.0
   Stream #0.0 -> #0.1
[msmpeg4 @ 0xb7f3c748]removing common factors from framerate
2005-01-08 23:05:15.412 Audio is 405ms ahead of video at # 5
Press [q] to stop encoding
2005-01-08 23:05:15.503 Audio is 365ms ahead of video at # 7
2005-01-08 23:05:15.571 Audio is 325ms ahead of video at # 9
2005-01-08 23:05:15.647 Audio is 285ms ahead of video at # 11
2005-01-08 23:05:15.718 Audio is 245ms ahead of video at # 13
2005-01-08 23:05:15.781 Audio is 205ms ahead of video at # 15
2005-01-08 23:05:15.870 Audio is 165ms ahead of video at # 17
2005-01-08 23:05:15.942 Audio is 125ms ahead of video at # 19
2005-01-08 23:05:16.010 Audio is 85ms ahead of video at # 21
2005-01-08 23:05:16.085 Audio is 45ms ahead of video at # 23
frame=   40 q=31.0 size=     326kB time=1.6 bitrate=1683.6kbits/s

<--- end output from nuvexport --->

Is there something stupid I'm doing wrong, or is this a known bug ?

Any more info you need ?

Any help would be much appreciated, its pretty much the only thing that 
doesn't work now on my 2 VIA EPIA myth boxes :-)

Lee