[MPlayer-users] -vf ilpack

[Ville Saari]

On Fri, Mar 05, 2004 at 08:24:17PM -0500, D Richard Felker III wrote:

> If you think about it, it's actually NECESSARY that sampling be done
> this way, since there's no way to tell reliably if a frame is
> interlaced or progressive.

I thought that DVD players would simply use progressive sampling for
progressively encoded mpeg and "ilpack" sampling for interlaced mpeg.

Theoretically that SHOULD be a reliable way to tell, but in reality
so many DVDs seem to be encoded by incompetent fools.

Several PAL DVD are encoded so that progressive film content was
converted to interlaced video, which was then encoded to DVD with
opposite field dominance so that every frame is like the interlaced
frames of telecined NTSC. I couldn't find a way to fix such video
with mplayer's existing filter arsenal, so I wrote my own "phase shift"
filter.

But some such DVDs are doubly blundered: Those interlaced frames are
encoded as progressive mpeg! There is no way to acceptably fix such
content because the fields will be partially blended together in the
decoded picture. If I use my phase shift filter on that, the result
is a weird combined ghosting and combing artifact: one field has future
ghost and the other field has past ghost.

-- 
 Ville