[MPlayer-users] x264 and loss of sync with B-frames

[Jason Tackaberry]

Using mencoder and x264 from tonight's cvs/svn.  I've been experimenting
with x264, and I've noticed that when I use B-frames I get output whose
number of frames increases with the number of B-frames I use, which
seems to directly affect A/V sync.

Here's the mencoder command I'm using:

   mencoder -dvd-device I_Robot.dvd dvd://1 -vf hqdn3d=2:1:2,crop=704:368:8:54  \
   -ofps 24000/1001 -oac copy -ss 6:00 -frames 250 -ovc x264 -x264encopts \
   bitrate=1500:pass=$PASS:4x4mv:frameref=6:bframes=10 -o clip.avi

Setting bframes=0 results in a clip.avi which is perfectly in sync.
Setting bframes=1 causes the clip to become slightly out of sync but not
very perceptible.  Setting bframes=10 or 15 causes it to become
noticeably out of sync.

Am I doing something wrong?  Or is this a bug in mencoder or x264?  Let
me know if you'd like me to upload the clip.

Cheers,
Jason.