Many BluRay, DVD’s and video downloads include HDCP (High-bandwidth Digital Content Protection) - in theory to help reduce digital pirating from HD disks or files when the source has a digital output such as HDMI, DVI or DisplayPort. Such copy-protected sources will only be compatible with more expensive HD distribution systems – including HDBaseT - where the manufacturers effectively pay an annual levy towards the copyright.
If you wish to play such copyright-protected material, then you will need to ensure that you have an HDCP-compatible AV/distribution system. NB. These will still not allow for recording from HDCP copyrighted sources.