[MEncoder-users] Choppy video when changing framerate

[Wolfgang Woehl]

Donnerstag, 14. Juni 2007 20:07 Phil Ehrens:
> Stanley wrote:
> > Manuel Carro wrote:
> > >     Using the -ofps option makes the video to definitely look choppy.
> > > And it is not a question of the player itself: the same video (after
> > > reducing the framerate) looks choppy when using mplayer, xine, totem,
> > > etc.  I assume that, to go e.g. from 25 to 20 (my current benchmark)
> > > -ofps could remove one out of each five frames.  But, when playing
> > > back, it looks as if those removals were not happening evenly, but
> > > rather in groups every second or so.  I do not think mencoder is doing
> > > that (is it?).  Any hint of what could be the problem (and the
> > > solution)?
> >
> > I have the same feeling too. The video does look choppy more or less
> > after changing FPS, especially reducing FPS a little bit (e.g. 25fps to
> > 24fps).
> > I think this is somehow unavoidable without rendering all frames again
> > which will bring much computation. As the interval of frames changes,
> > the content of frames must be changed in order to look really smooth.
>
> Exactly. Except in cases where ivtc works perfectly, reducing framerate
> is a lossy process. Transcode's modfps clonetype 3 (pixel interpolation)
> can produce very good results, however, and is a clever and elegant
> solution.

Could you post an example line for like converting a 30fps.avi (mpeg) to a 
25fps.avi? I tried and I don't get it. Yes, after reading 
README.filter.modfps :\ Thanks in advance.

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