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

[Zoltan Hidvegi]

> I haven't tested it yet and I'm a bit busy today, but you might check
> out the examples at http://brightrain.aerifal.cx/~dalias/video_examples.
> The "evil M" shows a particularly nasty scene change, as does

OK, I've looked at that.  When I mention frame numbers below, I start
then from 0.  My filter thinks that the first 10 frames are hard
interlaced.  They are quite noisy, I'm not sure what can you do with
them.  When my filter detects hard interlaced content, it will pick a
field based on the rate control, takes its two neighbors, and fills
the missing field from the better neighbor, and if it still looks
interlaced, it will drop the pixel from the neighboring fields and use
the average of the key field.

Frames 10-24 are detected as well telecined.  Frame 25 is detected to
have a scene change in the middle of the frame, and the first field of
frame 25 is not considered a good match for the last field of frame 24
because there is too much noise.  Then this field pair is droped for
rate control.  Maybe my heuristics could be changed to treat these
fields as a match.

Similar thing happens at frame 44, scene change in the middle, and the
first field is not a good match.  And while frame 43 was a perfect
progressive frame, its display was delayed for rate conrol, and now
the first field of frame 44 is shown, which happens to merge in most
of the last field of frame 43, so fortunately it still mostly does the
right thing.

After that, everything is fine again until frames 192-200, which are
horrible hard-interlaced frames, like an interlaced video fade-out was
added.  My filter does lots of deinterlacing here.

Then my filter thinks that frame 202 is interlaced, and it's dropped
for rate control.  The drop will not look bad, since it is the first
frame of the scene, but this frame sould be detected as progressive,
so my heuristics should be improved here.  After this, there is a
perfect telecine until the end, nothing is dropped.

The result looks OK, only two frames are dropped.

> lain-op-wire.avi. I can find much worse examples for you if you like.

In here, frame 3 has a bad edit scene change in the middle, the first
field of frame 3 does not match anything.  Then an other bad edit
between frames 3 and 4.  Again, the fields of frame 4 do not match
anything.

Frames 5-8 are like 30fps progressive frames.  Frame 9-31 are hard
interlaced.  Frames 32-76 are well telecined, frames 77-80 are
interlaced, and frames 81-107 are detected as 30fps progressive.
Frames 108-131 are interlaced, 132 is progressive, 133-135 are
interlaced, 137-143 are 30fps progressive, 144-149 are interlaced.

This is really bad, I do not know how can you get a good 24fps output
of this.  Variable rate seems to be more sutable for this, but my
filter still produces an acceptable result.

Zoli