Edit – I’ll add the pictures bak into this post in a few days.
If you buy or rent films from Apple iTunes in HD format, and then try to play them from a Mac on an external screen, you might get this error:
The selected film won’t play on one of your connected displays.
This film can only be played on displays that support HDCP (High-bandwidth Digital Content Protection).
This is a copyright thing and there doesn’t seem to be a way round it if the Mac thinks your connected display isn’t HDCP compliant.
You can however watch the non-HD version of the film or TV show if you want. Right-click on the film or TV episode in iTunes, and select Video Quality-Standard Definition (SD) from the pop-up menu:
May not be in HD, but useful if you want to watch something from iTunes on an external display.