[TheWEF]

Originally posted by valnar
So my question remains. If I watch a given 4:3 DivX movie in a window, I would want it unchecked to get a correct AR...

leave it checked, leave it checked, leave it checked,...


here are reasons i can think of to uncheck itu:

1) you know for certain that the dvd has not been mastered correctly.

2) you are willing to accept the (slight) ar-error, because...

a) you do NOT crop (keep the complete frame, no autocrop,...) a non anamorphic movie and want to play it on a 4:3 computer monitor (e.g. in 800x600, could be a lcd-video-beamer also or something else with vga-in) WITHOUT black borders. this means the movie will be resized to true 4:3 display aspect ration although technically this is not correct.

b) you do NOT crop (keep the complete frame, no autocrop,...) an anamorphic movie and want to play it on a 16:9 computer monitor (don't know, could be a hdtv video beamer in 1920x1080?) WITHOUT black borders. this means the movie will be resized to true 16:9 display aspect ration although technically this is not correct.

c) ?

...so only if you WANT INCORRECT AR.



here are the correct display aspect ratios for dvds:
display aspect ratio = width / height (square pixels)

PAL (720x576 not square pixels)
non anamorphic   = 1.367521 (close to 4/3  (1.333333))
anamorphic       = 1.823361 (close to 16/9 (1.777777))
NTSC (720x480 not square pixels)
non anamorphic   = 1.367088 (close to 4/3  (1.333333))
non anamorphic   = 1.822784 (close to 16/9 (1.777777))

note that if you crop off 8 pixels on each side you get 704x..., the resolution used in digital video cameras. this resolution uses the same pixel aspect ratio like 720x...
on a normal tv you never get to see these 8 pixels (usually a lot more than 8) because they lie in the "overscan area" outside the screen.
correct display aspect ratio for digital video camera material:

PAL (704x576 not square pixels)
non anamorphic   = 1.337132 (almost 4/3  (1.333333))
anamorphic       = 1.782842 (almost 16/9 (1.777777))
NTSC (704x480 not square pixels)
non anamorphic   = 1.336708 (almost 4/3  (1.333333))
non anamorphic   = 1.782278 (almost 16/9 (1.777777))

(so this is a method to fill a 4:3 or 16:9 screen completely keeping correct ar: crop off 8 pixels on each side )


none of these real world display aspect ratios really is 4:3 or 16:9, they are just called that way.
PAL-"4:3" is not even the same as NTSC-"4:3"...

i will remove the ITU checkbox in the next release.

wef