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Importance of this hint
Authored by: SOX on May 02, '03 01:11:05PM

this hit is potentially way more important than it sounds like.
the issue is that when you play a dvd movie if the screen is not
an integer multiple of the number vertical scan lines in the dvd
then the computer has to interpolate the pixels (horizontal pixels
always get interpolated I believe).

This leads to awful and visible effects on the screen when a
sharply defined edge (say a car door) moves slightly diagonally
across the screen. you can see visible zig-zagging far in excess
of what you might expect from aliasing effects. (I beleive the
reason for this is that the odd and even rows of pixels are stored
in alternate frames slightly delayed in time, the interpolation of
a fast moving object thus has the appearance of two out movies
on top of each other slightly offset).

you can see this effect most clearly on a projector when you
swithch the screen resolution so that it has to interpolate, to a
mode where it does not interpolate (and then re-zoom the
image back to the same size).

anyhow, it turns out that 800x600 screens are just shy by a few
pixels of being an exact multiple of number of scan lines in a
dvd movie. thus being able to forge the screen size to be an
exact multiple by losing just a few pixels on the overscan will
immensley improve the quality of the dvd movie. (interestingly
dvd movies look better on an 800x600 svga screen then they do
on a XGA or SXGA screen because the extra pixels dont give any
more resolution but do cause interploation distortion)

hence to the poster I ask how can I not only just get rid of the
black bars but also make it overscan so that it actually bleeds
off the screen?



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