Found this on the DPreview forum in regards to the output on the 5d Mark 2.
"5D Mark II shoots in 1080P, outputs 1080i from the HDMI connector. That means you can't output 1080P from the camera's HDMI port.
There's no "TV converts it back to 1080P" magic going on, or need to check your TV. You can't output 1080P from your camera.
If you want to see the full 1080P video, the easiest, and unfortunately expensive, option is transfer the mov file to your computer, use a Blu-Ray burner to create a Blu-Ray disc and play it back on your Blu-Ray player."