[MEncoder-users] low quality decrypt

[Guillaume POIRIER]

Hi,

On 9/21/05, Pete Davis <pete at petedavis.net> wrote:
> > Hi,
> >
> > On 9/21/05, Pete Davis <pete at petedavis.net> wrote:

[..]


> > >
> > > Modifying their example, I would do something like this instead:
> > >
> > > Pass #1:
> > >
> > > mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o
> > > /dev/null
> > >
> > > Pass #2
> > >
> > > mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac mp3lame
> > > -lameopts vbr=3 -o pelicula.avi
> >
> > I do not think this is a good example, though I have not double
> > checked myself: you should process "almost" the same audio data on
> > both pass, otherwise you may/will end-up with A/V desync.
> >
> > You may for example do -oac mp3lame -lameopts vbr=3:aq=9 on first pass
> > to reduce the amount of time sucked up by the mp3 encoding.
> >
> >
> 
> Guillame, I don't know about the inner workings of mencoder, but almost
> EVERY encoding I've done for the past several months has had -oac copy for
> the first pass and -oac mp3lame ... for the second pass. This includes
> mpeg-2 to mpeg-4 conversion from my hauppauage capture card, DVD to mpeg-4
> encodings, as well as mpeg-4/AC3 to mpeg-4/MP3 encodings.
> 
> I have never once experienced audio-video desync with any of my conversions
> using this method.
> 
> That's not to say it's not possible. I'm sure you know better than I. But I
> have never experienced it over a pretty wide range of encodings.

If you have not tried NTSC encoding, then that's probably the reason
why you have not experienced sync issues. I personally always use the
same kinda audio track on each pass, so I can't say what appends if
you don't do the same thing than what I do. However, I did read a post
on the ML with someone who experienced some encoding problems that
were due to not having the same kind of track on each passes.
Now, do the way you like, if it works for you, that's good. I just
wanted to warn you that this solution was not ideal (but what's to be
considered ideal when talking about video encoding?)

Guillaume
-- 
Reading doesn't hurt, really!
  -- Dominik 'Rathann' Mierzejewski