[popcornmix]

am i supposed to be able to play m4v videos?

m4v is just a container - you may be able to play it. They normally contain h264 which will play, but sometimes contain DRM (if bought from iTunes) which won't play.

This one is unusual - it is an mp42, which is an old non-standard microsoft variant of mpeg 4.
http://www.fourcc.org/mp42/

You can't play that on a Pi.