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Aspect Ratio, Borders, Resolution solved!
OK, guys! Solved the problem, thought everybody might like to know the results.
The problem was: take a video file at 640x480 (@1:1 VGA = 4:3 Display), encode it to DVD format (720x480, 3:2 DATA -- 4:3 DISPLAY); If you tell it to keep Aspect Ratio, it shrinks to 704x480. WHY?
The answer is, DVD format LIES when it says 720x480 displays at 4:3. It doesn't. It's wider. 704x480 displays at 4:3 (or 16:9, if you're going widescreen). Why this isn't better documented is beyond me, but I checked it out. I took a perfect circle in a video file, encoded it using 720x480 and 704x480, and literally measured how it displayed on screen with a ruler. 704 made a perfect circle, 720 made a wide oval, albeit very slight (10" x 9-1/2").
So, if you want to encode your own borders to protect against TV overburn, do your calculations on 704x480, NOT 720x480. In other words, take your X resolution (for me, 640), multiply by 480, and divide by 704 -- NOT 720. Voila! 436 is the correct Y resolution to keep A/R and protect against overburn, NOT 426. Hope this helps some people out, it sure was frustrating for me!
The problem was: take a video file at 640x480 (@1:1 VGA = 4:3 Display), encode it to DVD format (720x480, 3:2 DATA -- 4:3 DISPLAY); If you tell it to keep Aspect Ratio, it shrinks to 704x480. WHY?
The answer is, DVD format LIES when it says 720x480 displays at 4:3. It doesn't. It's wider. 704x480 displays at 4:3 (or 16:9, if you're going widescreen). Why this isn't better documented is beyond me, but I checked it out. I took a perfect circle in a video file, encoded it using 720x480 and 704x480, and literally measured how it displayed on screen with a ruler. 704 made a perfect circle, 720 made a wide oval, albeit very slight (10" x 9-1/2").
So, if you want to encode your own borders to protect against TV overburn, do your calculations on 704x480, NOT 720x480. In other words, take your X resolution (for me, 640), multiply by 480, and divide by 704 -- NOT 720. Voila! 436 is the correct Y resolution to keep A/R and protect against overburn, NOT 426. Hope this helps some people out, it sure was frustrating for me!
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