Ltterboxing help needed...

[Amit]

Hi,

I want to make my 4:3 aspect ratio capture from my camcoder appear as theatrical aspect ratio of 1.85:1.

Can someone tell me how much black border at the top and at the bottom do I need to match the 1.85:1 aspect ratio? I understand that I will be cropping my video from top and bottom to add borders.

Also if someone will be kind enough to give the exact formula to calculate borders for other aspect ratio's. I am in the NTSC world so an example for NTSC will be appreciated, if possible.

Magic Bullet Suite from Reg Giant Software has a plugin to do exactly this but its for Adobe After Effects and I am working in Adobe Premiere.

Thanks for your help.

-Amit Chugh

[scharfis_brain]

4:3 = 1.333333
16:9 = 1.777777777
17: 9 = 1.85
21:9 = 1:2.35

1.333 represents the full height (=100%)

so you need to devide the wider ARs by 1.33 the get the cropping factor:

(4:3) / (16:9) = 1.33333 / 1.7777 = 1.3333
=> divide the count of lines (NTSC=480, PAL=576) by this number:
480 / 1.3333 = 360
=> this is the vertical active picture area.

you need to crop away 120 pixels.

you may crop the 480 by each 60 pixels top & bottom, but I prefer cropping less on the top and more on the bottom, cause if you crop in a symmetric way (60 pixels each border), you also risk cropping away faces.

(faces are more interesting than feet or legs in general, exept those *errrrm* other cases....)

[Amit]

@scharfis_brain

Thank you for giving such a wonderful explanation along with an example. I will save this information some place safe so that I won't loose it ever.

I guess once I start using it more and more I will be able to memorize it well.

-Amit Chugh