SVD queries

Dear Dr. Rao

I got confused a lil bit when I started computing:

1. df from [df ff tf]=svd(dt)
2. df from [df dl]=eig(dd)

Also see your pdf of SVD MATLAB.

Why these two answers differ in magnitude as well as in sign?

But in practically both should be exactly same.

Also I found on wikipedia that
A=U S V1
A=U S V2
Mean: SVD is not unique?
Can you elaborate thses two points here.