[linda_22003]

It's hard to say that it violates copyright, though, since it does not change content, only the way content is viewed. I can watch any movie with the sound completely off and music playing in the background, if I want to - it does not change what's on the DVD.

[Hendrix]

I love it: use meaningless legal distinctions to win the argument. If it does not alter the DVD, there is no violation even though the same result would occur if the DVD were altered (i.e., the machine is altering what you see--not the DVD itself).