[mythtv-users] Problems playing MPEG2 from ffmpeg

[Tyler T]

Using a command like this one:
http://threebit.net/mail-archive/mythtv-users/msg43546.html , I want
to convert HDTV from a PCHDTV-5500 down to SD so it will play on a Via
Epia w/ the integrated Unichrome/XvMC MPEG decoder (the 600MHz CPU is
too slow for anything else).

My Myth frontend is perfectly happy playing back MPEG2 video from a
Hauppage-PVR150, but barfs on ffmpeg's "-target dvd" output. I have
successfully converted a 1080i stream to DVD resolution which plays
great in VLC. In Myth, though, skipping or seeking results in MPEG
artifacts (like a scratched DVD) and I get lots of these in the log:

[mpegvideo_xvmc_vld @ 0xb72e43c8]current_picture not initialized
AFD Error: Unknown decoding error
[mpegvideo_xvmc_vld @ 0xb72e43c8]warning: first frame is no keyframe
VideoOutputXv Error: Child     A        was already marked as available.

Finally, it dumps me out of playback but no errors are logged except
the ones above.

I have Googled these error messages with no easy answers. Does anyone
here know what ffmpeg settings I need to use so that Myth can play the
resulting file properly?

Thanks,
___
 /yler