hello !
you are right to work in 640 480 with a pixel ration of 1...
this is for a "basic" ntsc
but there is other format... like NTSC DV wide screen, NTSC D1 with a pixel ratio of 1 or a pixel ratio of 0.9...
For TV work, today in my post production company, the final output we deliver is 720/486 with a pixel ratio of 0.9.
and when i work with video footage comming from a inferno grab, i use this setup.
but if I need to create an animated sequence with footage that i create in illustrator, flash, photoshop, my setup is 720*540 pixel ratio 1.0, and after i comp the final work in a 720 486 pixel ratio 0.9 , by applying a 90% scale on X and Y it fit the comp perfectly.
with this method the circle shape doesn t look like a oval and the square to a rectangle on the computer screen.
for graphic animation with very thin edge, if your computer allow you to do so, i would suggest you to double the resolution of 720*540 and after do the scale to video res output. this can avoid hard edge on high contrast area of the screen by creating a "natural" blur with the scale.
I really hope this will help you !
feel free to ask again things that seem obscure!
because i am french and my english not so good...
last tips
when you render or setup a composition in after effect, there is something called PRESET to help you to choose what you need.
good luck!
yann
