[downloaded/watched a certain SW movie torrent,
which me got to thinking about the original trilogy,
found this site, and jeez now the sun is coming up!]
but I just have to comment on this PAL -> NTSC topic.
The thing I never see people consider is the following:
You have a 4:3 PAL image of a letterboxed picture.
You capture it at XXX x 576 lines.
You EXTRACT the middle 480 lines.
By doing this and displaying them on a 525 line system,
you have stretched the image vertically by 576/480=1.2
Since you wanted to maintain correct aspect ratio,
you need to stretch horizontally by the same factor.
Thus your display aspect ratio would need to be
(4/3) * 1.2 = 1.6 to see the extracted 'box' right.
Hmmm... Let's think about 16:9...
An anamorphic 16:9 DVD image is one where the 720 horizontal pixels
that would 'normally' fill the width of a 4:3 display are stretched (there
is that word again) by a factor of 1.333. You don't get a higher resolution,
but you do get (need) a display aspect ratio of (4/3) * (4/3) = 1.777
And here (extracting middle 480 from PAL image) we have a case
where we also want to stretch the pixels horizontally to get the
aspect ratio back to being correct. In this example, the horizontal
stretch is 1.2 vs 1.333, but the point is that so far I haven't touched
the data... No complex 2D mathematical resize operations on the
sampled data at all (which always introduces some artifacts / errors).
How does one tackle the 1.2 vs 1.333 = 10% DAR diff? Well, how
about not using the full width of the 16:9 display? A good portion of
that 10% differance is in the overscan area anyway, why not keep
ALL of the sampled data in the viewable portion of the 16:9 display?
For what it's worth, I've used a similar approach a few times in the
past when converting PAL SVCDs to NTSC DVDs, and it really makes
a difference in the quality of the result. Food for thought...
Anyway, I'm really amazed and excited at all the preservation projects
(past, present, and future) being discussed in this forum, and hope I
can contribute in some small way...