[MPlayer-users] Re: [-] Re: [-] Re: [-] Best de-interlace filter ( NOVIRUS )

[Matthias Wieser]

Am Montag, 11. Oktober 2004 05:21 schrieb D Richard Felker III:
> On Sun, Oct 10, 2004 at 09:32:41PM +0200, Matthias Wieser wrote:
> > Am Sonntag, 10. Oktober 2004 02:29 schrieb D Richard Felker III:
> > > On Wed, Oct 06, 2004 at 08:21:19PM +0200, Matthias Wieser wrote:
> > > >
> > > > Dscaler and TV-Time do have some high quality deinterlacers.
> > >
> > > i wouldn't call them high quality. your eyes just compensate
> > > because of the high refresh rate (50/60 fps).
> >
> > You can configure TVtime and Dscaler to give 25/30 fps.
>
> that makes the quality much lower and eliminates the purpose of these
> programs.

I often use 25 fps and the quality is very good. At least better than 
mplayer + pp=fd or pp=lb

YMMV

> > > but if you encode the output of
> > > these it'll take insane bitrate because of the high frequency
> > > flicker your eyes cover up. so from my standpoint it's very low
> > > quality.
> >
> > ??
> >
> > I don't see how a deinterlace filter like
> >
> > if pixel needs deinterlacing {
> > 	deinterlace
> > 	make nice edges
> > } else {
> > 	do nothing
> > }
> >
> > has to produce flicker.
>
> what does "if pixel needs deinterlacing" mean??

I don't know the exact algorithm those deinterlacers use but it should be 
some kind of motion detection code.

> ideas like this come from an incorrect assumption that interlaced
> video is a sequence of frames with possible combing.
> interlaced video is a sequence of fully independent fields which are
> undersampled by 1/2 (and thus horribly aliased).
>
> sometimes you can use the previous (or next?) field to fill in missing
> lines of a field. but deciding if/where you can do this is a very
> inexact art, and very error-prone.

It can be done in different ways. Some work quite well. 

> > > anyway this isn't it's most
> > > serious fault. the main problem with md is that it destroys all
> > > local extrema in the picture.
> >
> > That's true - at least for extrema only one pixel high. But I have
> > never seen this effect. So I would say it's a minor problem. The most
> > visible problem is the staircase effect on edges.
>
> essentially all extrema are only one pixel high.

Extrema like highlights often extent over more than one pixel. Then the 
difference between the actual pixel value and the one of the brighter 
neighbour is not that large.
 
     Matthias