Maybe I have some tips for your 'ratio-problems'....

I have had some troubles myself, but now it seems to be OK.

I make screencaptures with Media Player Classic. This provides me pictures of 720x576 pixels.
Mostly on the DVD is written what the ratio is, 4:3, 5:4, 16:9.

4:3 = 1.333333333333
5:4 = 1.25
16:9 = 1.85

I make this sum (I don't know a good word for it, sorry).

720 / 1.33333333 (depending on the DVD ratio) = 540.
Then I make the picture 720x540 pixels.

You can also do this with a width you want (640 / 1.333333333 = 480, so 640x480).

P.S.

If I have time tomorrow, I will upload them (if imcdb is up...)