Question on aspect ratio and resolution

[kitfox4]

What is aspect ratio mathmatically? is it vertial resolution divided by horizontal?

I have this widescreen japanese video and on the back it says it's got an aspect ratio of 4:3 but when i use that setting it makes the video fit a 'normal' screen and loses it's widescreen resolution and messes with the quailty. How should i know what ratio a movie is and what resolution to use to maintain highest quailty while still compressing?

I just took a guess and did vertial divided by horizontal for 1.5 aspect ratio and used that and it seems to look the most like the original. Then i put the output as the same as the input for resolution. Was this the right choice for the highest quailty? or maybe i'm missing something.

Thanks for any help.

[Soulhunter]

Easy...

A DVD can only have one of two "real" AR's !!!


- Option 1 = The DVD has a AR of 4:3

- Option 2 = The DVD has a AR of 16:9


Other AR's are not possible for a DVD that follows the standards...

The info @ the backside tells you mostly the AR without the black boarders !!!

To get the right AR while cropping...

Resizing to one of the two above AR's first (which fits/looks right) and then crop the boarders !!!

Now you should have the right AR...


Example:

You have a PAL movie (so its 720x576 @ the DVD)...

Now you resize it to a 4:3 AR (like 640x480) !!!

If the resulting preview looks not vertically stretched, you know it has a 4:3 AR...

If it looks stretched, resize to a 16:9 AR (like 512x288) !!!

Next step...

Now crop the boarders @ the top n' bottom (if it has boarders) !!!

For the 16:9 (512x288) example..

Lets assume the boarders are 20 @ the top, and 20 @ the bottom !!!

Now you have a resolution of 512x248...

As 512 : 248 = 2.06, you movie has a AR of 1:2.06 (rounded) !!!


Bye