[MEncoder-users] low quality decrypt

[Guillaume POIRIER]

Hi,

On 9/21/05, Pete Davis <pete at petedavis.net> wrote:
> > > the marvelous MPlayer documentation found at
> > > http://www.mplayerhq.hu/DOCS/HTML/en/index.html .
> > > Pay special attention to chapters 7 and 8, which go into detail on the
> > > mysteries of video encoding using MEncoder.
> >
> > Really, I tried to do so. But i simply couldnt understand much. My
> > problem is that i know nothing about image/video processing. To be
> > honest, i tried with the spanish version, but i see now it is some out
> > of date. And i get lost with the english version.
> >
> > However, the real problem _for me_ is, imho, the high level (or not
> > for novice) of the help. I think it requires a previous knowledge of
> > video stream, formats, etc etc
> >
> > Newcommers, like me, just pretend to decryp a dvd without having a
> > deep knowledge of all the posibilities that mencoder provides.
> >
> > As time goes by, i will try to impruve my output files, once i get a
> > deeper knowledge and practice with mencoder.
> >
> 
> Miguel, I agree, as a beginner, I found the documentation very hard to
> follow because you do really need to understand quite a bit about video.
> 
> I found that simply trying to encode a bunch of different things, reading
> about and trying different parameters, and looking at the results, thing
> slowly started to make more sense to me. It does take a while to start
> feeling comfortable with all the terminology and different things you need
> to know.
> 
> For encoding DVDs, you really need to read through Chapter 8 (unfortunately
> it hasn't been translated into the Spanish version!).

If you are willing to translate it, I'm sure that this will be greatly
appreciated.


[..]

> Unfortunately, the example in the Spanish docs (7.1 Codificacion MPEG-4 en 2
> or 3 pasadas) is not a particularly good example. It does a 2 pass encoding
> but does a 3rd pass for audio which isn't necessary.
> 
> 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.


Guillaume

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