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Old 3rd February 2006, 12:02   #7  |  Link
yaz
n00b ever
 
Join Date: May 2002
Posts: 627
cropping does not change the way of derivation (resizing). if u crop the stream (sar) u 'crop' also what u get on the display (dar). u'd better think of it as 'how to distort each pixel so as to get the right aspect ratio on the display'.

say, u got a pal 4:3 dvd. its stream size is 720x576 (by def) which is 5/4 ratio. it must be displayed 4/3 so as to get the correct ratio on the display, so, it must be resized to 768x576. it is the same as displaying each pixel in a 16x15 rectangle instead of a 15x15 square (measured in whatever unit).
if u crop it to 704x576 (for any reason) it must be resized the same way, so the display size must be ~751x576. otherwise the picture on the display will be distorted.

it's simple as that

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