A little help regarding aspect ratios - Calculations Involved.

My LCD TV's aspect ratio is 16:9 (1280x720), but my laptop will only display video of 1280x768 to it but stretched to 1280x720 resolution (things on the screen look slightly shorter and wider than they're supposed to be).
I can play 16:9 movies fine, by just stretching them to fill up the screen, but for 4:3 movies, I'm a little confused to what I should re-aspect them to..

So lets say the video is 640x480, and it's height is stretched from 720 to 768 pixels, so 480/768*720 = 450 pixels, so we have video looking like 640x450 pixels (a bit wider looking), but it needs to look like 480 pixels, so then we convert the thing, we have 0.75 (3:4, which is 4:3 but reversed, concerning the height) aspect for the height = 450 pixels and to make it 480 I can do 0.75/450*480 = 0.8. And 0.8 is equal to 4:5 which in aspect ratio terms is 5:4.

So does that mean I can simply (too convenient really..) re-aspect the video's inside the video player from 4:3 to 5:4 to get the correct aspect when I'm watching on my TV or did my mathematics just implode?

 

I dunno about your math, but my brain just imploded X_X

Can't your laptop display 1280x720?

 

It can, but my TV just gives a black screen for some reason.. I've tried re-installing drivers etc, but nothing.