[MPlayer-users] xvid encode from HDTV MPEG audio sync problems...

[Jason Tackaberry]

On Mon, 2006-01-09 at 09:37 -0500, Steve Adeff wrote:
> mencoder inputfile.mpg -oac copy -ovc xvid -vf pullup,softskip,scale=960:544 
> -ofps 24000/1001 -xvidencopts 
> pass=2:max_iquant=3:max_pquant=6:max_bquant=7:vhq=0:me_quality=5:turbo:quant_type=mpeg:aspect=1.78:bitrate=-595000 
> -o outputfile.avi

You shouldn't use turbo on pass 2.  And do you really need to specify
the max quantizers like this?  Is xvid seriously undershooting the
target size?

> The problem is, the huffyuv file created is like ~40gig, so being able to do 
> it directly would be much better.

With a single pass, you could just use a pipe, but of course this
doesn't work with 2 pass.  Although in that case you probably couldn't
use a negative value for bitrate, since it won't know how long the video
is, and so couldn't calculate the appropriate bitrate for the target
size.

> So, am I doing something wrong thats causing the audio sync problem, is there 
> a bug? How do I figure this stuff out to see if it can be fixed?

This problem is likely caused by the use of B-frames, which mencoder has
problems with. You can disable B-frames with max_bframes=0.
Alternatively, you could remux the file afterward.  I usually still use
B-frames, but remux to a matroska file with mkvmerge.  Although it often
requires specifying --delay to compensate, which requires some manual
intervention to get the appropriate offset.  If you want to automate
this completely, your best solution is to disable B-frames.

Cheers,
Jason.
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