[MPlayer-dev-eng] [PATCH] frameno file

[D Richard Felker III]

On Thu, Mar 03, 2005 at 01:42:37PM +0200, Oded Shimon wrote:
> On Thursday 03 March 2005 03:19, D Richard Felker III wrote:
> > I agree with reasons 1 and 3, but not reason 2. The existing behavior
> > is very stupid (if you happen to have a frameno.avi file around it
> > will screw up mencoder like crazy), and this frameno pre-pass stuff
> > should be phased out anyway. It's already been removed or marked
> > deprecated in the docs, iirc, so it's totally acceptable to change how
> > it works, or even remove it altogether imo..
> 
> I agree too... Till a while ago I really had no clue what that frameno.avi is 
> for (it's completely undocumented, I figured it out from foriegn language 
> docs)... I thought it was a default input file or something... And even now 
> that I see what it's for, I find it kinda silly, because you can still use 
> -audio-file or something like that, I don't see the need for this frameno.avi 
> (not to mention, I'm not sure how it works out with my multiple file.. I 
> didn't test it because I don't understand it...)

No, frameno is totally different from -audiofile. The way it works is
you generate an avi file with audio and frame skip/dup control during
a prepass, then encode the video in two following passes once you know
the audio size and a/v sync. The problem is that this prepass doesn't
even decode video, so it can't possibly know the correct skipping or
duplication to do!! If you use no filters it's normally mostly right
(but there are still some exceptional cases where it can be wrong),
but lots of users just used it to encode audio first so they'd know
how many bits were left for video, and then of course they generated
broken files when they tried to use inverse telecine, etc.

Rich