Addison,

Why don't you use HANDBRAKE ?
It helps you to keep the aspect ratio (Video / Picture Settings / mark "keep aspect ratio / Anamorphic : none) then you change one of the sizes and it adapts the other one as best as possible.

1,76 ... but it's 16:9 video !!!
Didn't you read all the settings I gave in this thread ?!

I worked a lot on this, so please, at least, read it and try it !