Aspect Ratio

Ok...so I uploaded my first video from You-tube and the file was huge with an aspect ratio of 854 X 480. I had to do a little research to find out how to re size the video to a smaller size. I found out the the post column area is about 400, therefore the video's width being 854 extended into the sidebars of my blog template. I was able to edit my post and change my aspect ratio in the original copied script to 395 x 325. This seemed to work well! Help menus and blogger how to blogs, work wonders!