[mythtv-users] x264, interlacing, and mythcommflag --rebuild

[Gavin Peters]

Folks,

There's a few parts to my question, but I think they're related and of
general interest.  I'm trying to archive some older SD content that
got broadcast to me in 1080i.  So, I run something like:

mencoder $INPUT -oac copy -ovc x264 -vf crop=1440:1080,scale=640:480:1,il=2,harddup -x264encopts bitrate=$BITRATE:pass=1:turbo=2:partitions=none:qcomp=0.7:bframes=2:b_pyramid:threads=4:interlaced -lavdopts threads=1 -o /dev/null
mencoder $INPUT -oac copy -lameopts preset=medium -ovc x264 -vf crop=1440:1080,scale=640:480:1,il=s,harddup -x264encopts bitrate=$BITRATE:pass=2:qcomp=0.7:subq=6:frameref=3:partitions=all:8x8dct:bframes=2:b_pyramid:threads=4:interlaced -lavdopts threads=1 -o $OUTPUT

And that works, at least it makes a quite playable video.  There's some things odd about
the output file though:

Audio sync seems to go badly when I play it in the mythplayer; this
isn't fixed by -mc 0 -noskip, or any variation thereon.  Oddly, the
transcode duplicateds ~ 6 frames right up, then it just stops
duplicating frames.  Very strange.

See the il=s in the -vf above?  Without that, the interiacing on the
output file is backwards.  How weird is that???

And, after getting my output file, I try:

mv outputfile.avi original-show-file.mpg
mythcommflag -f original-show-file.mpg --rebuild

and I get some output, but seeking doesn't work.  If I seek, the video
is all crazy for a few seconds.  As well, the commercial break
flagging seems nicely broked by my transcode.

Advice?

- Gavin