bobbydigital80

Q: Questions about DVD aspect ratio

I'm trying to better understand the aspect ratios of DVDs and how they're displayed. I've read that all DVDs, whether 4:3 or 16:9, are 720x480 pixels.

 

If you have a fullframe pan & scan DVD and display it in its native 1.5:1 dimensions, how would this look? Does it look horizontally stretched? And is showing it in 4:3 just a matter of squishing it horizontally until it's 4:3?

 

And if you have a 4:3 letterboxed DVD, does it do the same thing as above and the only difference is black bars are encoded in the top and bottom of the frame?

 

If you have a 16:9 Anamorphic DVD, which is also 720x480 pixels, how does it look if displayed in its native 1.5:1 ratio? I don't quite understand this and I'm just curious how it would look compared to a 4:3 DVD.

 

Also, since pixels on a DVD are rectangular, I don't understand how the 720x480 ratio is 1.5:1. To me this only makes sense if the pixels are square because then the width and height would be the same.

 

If the width of a pixel is longer than its height, you can't divide them to get the aspect ratio, right? For instance, if you had a frame of 15 pixels wide and 10 pixels high, and if the pixels are 2 inches wide and 1 inch high (for the sake of argument), then the width of the frame would be 30 inches (15 pixels times 2 inches) and the height would be 10 inches (10 pixels times 1 inch). This would give an aspect ratio of 3:1. It would only be 1.5: 1 if the pixels were square. So how does a 720x480 DVD with rectangular pixels come out to 1.5:1?

 

Thanks to anyone who can clear this up for me!

MacBook Pro with Retina display, OS X Yosemite (10.10.5)

Posted on May 14, 2016 2:50 AM