[mythtv] [mythtv-commits] mythtv commit: r15109 by gigem

Doug Larrick doug at parkercat.org
Tue Dec 11 01:17:29 UTC 2007


Kevin Kuphal wrote:
> Is there anywhere online with information about how these deinterlacers
> vary from say, bob, and why we might want to use them over any other
> de-interlacer?  Thanks.

Bob (2x), Yadif (2x), and GreedyH (2x) all turn 30 Hz (or 25 Hz)
interlaced video into 60 Hz (or 50 Hz) progressive video.  The other
(non-2x) deinterlacers output 30(/25) Hz progressive video -- which
looks fine for static scenes, but motion tends to look jumpy.

Bob does this by showing first one field, then the other, scaled to the
entire height of the picture.  Hence, for low- or no-motion scenes, bob
is discarding half the vertical resolution of the picture.

These new deinterlacers attempt to recover additional spatial
information by looking forward and/or back in the video stream.  I
believe GreedyH looks only at the prior field, while Yadif looks both
forwards and backwards.

IMHO they are a huge improvement over plain bob, especially when
zoomed-in on letterboxed material.  They (especially Yadif) make
standard-definition playback look as good as I've seen it.  Their CPU
consumption, however, is quite high on HD-sized frames.

http://guru.multimedia.cx/deinterlacing-filters/

...and a couple of screenshots I took:

http://www.parkercat.org/doug/greedyh.jpg
http://www.parkercat.org/doug/yadif.jpg

-Doug

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