[MPlayer-users] Alternative 3-pass methods

[lt at speakeasy.net]

> > When I add -mc 0 and -noskip, it starts off fine, but very slowly and
> > gradually drifts out of sync.  
> 
> Have you tried -mc 0 without -noskip?  It may be that you have mixed-fps
> video, and it can't drop frames to maintain 23.976 output when the video
> switches to 29.97, or whatnot.

Actually, I have.  It drops a couple frames of darkness at the beginning of the DVD, before it realizes that it's 24 fps.  And I think there is one section in the middle where it's 30 fps for about 5 frames (why?).  All told, it makes a difference of 4 frames for the entire movie.  So that's not the problem.  I've been playing back the result file with different -fps, but I haven't found a value that keeps it in sync yet...  this process is tedious.

> > I would like to do 3 pass encodes without having to deal with
> > frameno's brokenness.
> 
> What's wrong with 2-pass encoding?  Sure, you encode the audio twice,
> but it's such a small part of the encoding process that it's not
> noticable.

When you turn up lame's quality, say with aq=0, it takes forever (for current lame, at least).  Granted, I don't need aq=0... it's hardly better than the default, but hey, why not.  But that's not really my main reason for wanting do do this.

The main reason is that -oac lame, with recent lame, introduces slight a-v desync.  Only a few frames, but enough so that I notice it during dialogue on live-action films.  I'm told this is because Mencoder doesn't adjust for lame's internal buffering, or something like that.  It really is barely noticeable, I can't tell at all on animated material.

So I can either downgrade lame, switch to -oac lavc, or figure out how to make this work.  I'd like to make this work, because I like lame.

> Anyhow, for editing reasons, I do something like reverse 3-pass
> encoding.

I've used that method before, usually when I'm editing in subtitles, because most video editing software HATES vbr audio (WHY?).  Works pretty well, I think.