[MEncoder-users] Re: audio sync problems encoding from vob

[Paul MacIain]

Christopher M. Jones <cjones <at> partialflow.com> writes:

[Post rearranged.  Don't top-post.]

> On Thu, 2006-06-22 at 10:43 +0200, scostas wrote:
> > RC wrote:
> > 
> > > The HTML docs have very good instructions on making standards-compliant
> > > files (VCD/SVCD/DVD).
> > 
> > More precisely, you have the instructions here:
> > 
> > http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-vcd-dvd.html
> > 
> 
> Yes, it did create an avi. My mistake. 
> 
> However, I did follow the instructions on this page, and when I use
> them, e.g., the line further down on the page
> 
> mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd -vf
> scale=720:480,\
>   harddup -srate 48000 -af lavcresample=48000 -lavcopts vcodec=mpeg2video:\
>   vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:keyint=18:acodec=ac3:\
>   abitrate=192:aspect=16/9 -ofps 30000/1001 \
>   -o movie.mpg movie.avi

What makes you think this is the correct combination of options?  13.7.5.4
matches your source video much more closely. Randomly picking a sample command
line is unlikely to produce the desired result.

> I get many many duplicate frame messages and the file is way out of sync. Using
> avisync on the resulting file gives me periods of noise in the file. The best 
> results came from the line I quoted earlier, 
> 
> mencoder -o 01_firstcontact.avi -ovc lavc -lavcopts
> vcodec=mpeg2video:vbitrate=5000:vhq:acodec=ac3  -oac lavc  -srate 48000
> -ofps 24000/1001 VTS_01_1.VOB
> 
> Only a handful of duplicate warnings at the very beginning, one skipped
> frame, and an -almost- perfect sync when played in mplayer, perfect in
> vlc and xine.

Yes, but this produces an AVI, not a DVD ready MPEG stream.

Three things: 

1) The sample command line that you selected has -ofps 30000/1001 ; this does
not match the source fps. -of mpeg -mpegopts format=dvd:telecine -ofps
24000/1001 allows 24000/1001 fps progressive content to be encoded at 30000/1001
fps whilst maintaing DVD-compliance. 
2) Why are you reencoding the audio?  It's already AC3.
3) Please read the documentation when you are directed to it, rather than
skimming it and trying commands at random.  Understanding what you are doing
makes obtaining the desired result a lot easier.