Since High Definition video came out on all the online sites it has changed the default aspect ratio of the player from 4:3 to 16:9. This means that for people posting SD video you have to resize some of your videos to get them to fit right.

For example, NTSC DVD quality (aka 480i/p) is 720x480 pixels (width x height). However, low-end High Definition (720i/p) is 1280x720.

Anyway, now that the video players are built for HD you will find that uploading standard quality videos will result in videos that are "letter boxed" which means they have extra black bars on the top and bottom (or sides).

Correct me if I'm wrong, but in order to get a 720x480 video to fit a box that is designed for HD the best practice would be to crop some of it off so that it fits as 720x404 since:

16/9 = 1.78 (1.7777777777778) 

720/405 = 1.78 

405x1.78 = 720.9 

The same would stand for 640x480 (old TV quality) video that would need to be 640x360 correct?

I'm asking because I'm not sure about all this and whether this is the proper way to fix these letter-boxing/display problems.