[MEncoder-users] NTSC VOB issues

[Phil Ehrens]

Dominik 'Rathann' Mierzejewski wrote:
> On Wednesday, 05 January 2005 at 01:44, Phil Ehrens wrote:
> > raregister at comcast.net wrote:
> > > Hey folks first post but not a total newbie.
> > > 
> > > I've gotten mencoder to work but I've got a small problem w/my encoding.
> > > 
> > > if I don't use -noskip the video syncs nicely when I mux it through VirtualdubMod  w/its AC3 file, but the film is... jerky.
> > > 
> > > When I use -noskip the jerkiness is GONE, the films is nice and smooth, but the framerate goes wacky.
> > > 
> > > ..... so I've played with -ofps and it works IF the frame rate in the vob doesn't change.
> > > 
> > > The problem is that on some movies it jumps from 29.97 at the begining to 23.97 for the full movie.
> > > 
> > > That of course blows my sync right out of the water.
> > > 
> > > Any tips/thoughts would be MUCH appreciated.
> > 
> > Hmm... I just do this, and the changing frame rate is handled
> > automagically by mencoder:
> > 
> >  mencoder -oac copy \
> >           -ovc lavc \
> >           -lavcopts vcodec=mpeg4:mbd=2:qprd:v4mv:vqscale=2:trell:vbitrate=2400 \
> 
> Are you getting better results with qprd then without?

Not sure, since I don't know where to look to find out.
Do I look at sharp edges, at color gradients, at soft edges?
I used it because a seemingly knowing article suggested it,
and since ffmpeg encoding is so darn fast the performance
hit was not a problem.

> >           -ofps 23.976 \
> 
> FYI: this should be 24000/1001 (or 30000/1001 for "29.97").

Ah, I didn't realise I could express it as a ratio... but:

phil at t22: ~ >>bc -l
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'. 
24000/1001
23.97602397602397602397
30000/1001
29.97002997002997002997> 

Under what circumstances could it possibly make a difference?

Phil
-- 
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