Right strange questions - I have just noticed my 10m hdmi cable is not guaranteed as carrying a 1080p signal over 10m - this runs from my av amp to my projector so carries no sound - my projector would automatically upscale any signal sent to it to 1080p to output it if receiving a lesser signal or just pass through original signal at 1080p - how do i know if my projector is receiving a full 1080p signal from the source and not dropping to 720p because of the legth of the cable and then being rescaled to 1080p by the projector?