[MPlayer-dev-eng] New inverse-telecine filter

[D Richard Felker III]

On Tue, Dec 02, 2003 at 10:10:08AM -0600, Zoltan Hidvegi wrote:
> This is a new inverse telecine filter, similar to detc, ivtc and pullup,

OK, I finally tried it, and here's my evaluation...

The main problem I see is that it's too quick to switch to
hard-interlaced mode instead of inverse telecine. If it switches even
for just one frame in the middle of a telecined sequence, you get a
_nasty_ flicker to low quality, especially if there's any small text
or other fine detail on the screen. This is very visible in
lain-op-hardlaceboy.avi, and to a lesser extent in lain-op-evil-m.avi.

Furthermore, it outputs at least one combed frame on all of the
following clips:

lain-ep6-bogus-pulldown.avi
lain-ep11-blurroom.avi
lain-ep11-bogusmouth.avi *
lain-ep11-laser1.avi
lain-ep11-laser2.avi *
lain-ep11-pronsite.avi
lain-ep11-zoomout.avi
lain-op-combedbird.avi

A couple of these, "bogusmouth" and "laser2", are not fair examples
because there is no correct way to inverse-telecine them. They're
horrible botched edits. But the rest should be handled perfectly, and
in fact are handled perfectly by detc, ivtc, and pullup as far as I
know.

In case you're wondering, the files in the main examples dir are
troublesome clips for any inverse telecine engine, whereas the few I
put in the "zoli" directory are ones that should be easy, but which
your filter messes up badly.

BTW, I also found a couple bugs in your code. I'm not sure why, but
output is horribly corrupted when rendering

  vd --dr--> pullup2 --export/alloc--> vo

but the bug goes away when I change the filter chain to:

  vd --slices--> scale --dr--> pullup2 --export/alloc--> vo

Also there's a compiletime bug: C++-style variable declarations
midfunction in dint_copy_line_mmx2.

BTW, if you're curious why all my sample clips are from Lain,
everything else I have that I've tried to inverse-telecine has been
trivial -- naive algorithms work fine. There are some other
contributed clips you could check, some of which have problems with
your filter. But many of these are broken or pathological cases and
perhaps not worth considering...

Hope this info helps!

Rich