[MPlayer-users] deinterlace+horiz scale

[D Richard Felker III]

On Sat, Jun 05, 2004 at 06:34:25AM -0700, rcooley wrote:
> On Sat, 05 Jun 2004 06:52:43 +0400
> Mikhail Ramendik <mr at ramendik.ru> wrote:
> 
> > Oops, found -vf field.
> > 
> > And it (-vf field,scale 768x576) did give me the necessary fps for
> > realtime!
> 
> I was trying out "-vf field" a while back, and I found something
> strange.  It seems the quality is much better if I just use scale to
> halve the vertical resolution, rather than using field.  -vf field
> resulted in stair-stepping lines, and just an all-around much lower
> quality picture, while halving the resolution with scale produced a
> picture that looked very nearly as good as full-res.

And it also has ghosts whenever there was motion!! VERY VERY BAD!!
(Same thing as pp=lb :) It's especially bad if your video happens to
be telecined rather than 50/60 fps interlaced, since the ghosts will
flicker in and out and be 2.5x as large when they do appear.

> It's always possible it could have been a bug in the version of MPlayer
> I was using, but I thought I'd mention it just in-case it wasn't, and if
> others want to try it out...

No, it's a "bug" in the brains of the idiot engineers who designed
interlacing. Interlacing is inherently flawed because both fields are
undersampled (and thus they alias) unless there're no motion (in which
case you can use the previous/next field to repair the current one).

Rich