When video bitrate is expensive (>20Mbps), some renderers (TV) (could) becomes unresponsive - doesn't react on remote commands any more.
You can check Video Bitrate with Bitrate Viewer tool:

http://www.videohelp.com/tools/Bitrate_Viewer_2

{{ :bitrate_viewer_2_1164.jpg?nolink&500 |Video Bitrate Viewer}}