A function than when set, will lock out any changes like volume, playback or brightness changes being made via the touch screen interface.
My reasoning for this function is that I often play very long files, as long as 10 hours. These have audio but no video and I often carry the phone in my pocket while listening. I can't lock the device because the application stops playing. Keeping the device in my pocket but unlocked means that the program often pauses, stops, rewinds, changes volume, etc, due to small touches to the face of the device.
If there were a way to lock out the playback controls temporarily this would cure this issue.
Another small suggestion would be a way to turn off video completely, to save battery life if the user is just listening and not watching.
Thanks for a great product!