3 Major Challenges of HDMI Installs and How to Tackle them

The first is that all devices in the system, from source to display, must be HDCP-compliant. That may seem obvious to a residential integrator, but commercial A/V integrators may not be fully aware that just a single, non-HDCP compliant device, such as a simple HDMI switcher, can disable Blu-ray disc playback for the entire system.

Second, commercial system designers need to be aware that HDCP rules allow for a maximum of 127 devices downstream from the source, with up to seven levels of repeaters allowed. Certain source devices including Blu-ray disc players have been known to allow for much less than 127 downstream products, often even less than 16.

The third important consideration for commercial A/V integration and content protection is that copyrighted music and video, whether protected by HDCP or not, is intended for personal use in a home or other private locale. Many commercial A/V applications, on the other hand, will be in public spaces. If the installation will be in a convention center, restaurant, retail outlet, or other public location, playing copyrighted content will be restricted unless the customer has made agreements with the content providers.

For playback of HDCP-protected material, a multi-step handshaking and authentication protocol is necessary between connected devices. This two-way communication is always active and must not be interrupted. Therefore, as with EDID, HDCP presents a challenge when it comes to signal switching and distribution. For an HDMI switcher, HDCP communication may result in a delay of up to several seconds after signals are switched, as the sink (display or other output device) handshakes and authenticates itself to the newly switched HDMI source.

Splitting or routing an HDCP-encrypted signal is difficult, because the communication protocol requires extensive re-negotiations whenever a source device senses newly connected destination devices. Technologies have been developed and continue to evolve, that allow for continuous HDCP communication between devices when encrypted signals are switched or distributed.

Some residential and commercial A/V integrators have decided to work around the issues related to HDCP by deploying analog-based video signal routing. This is a temporary solution, since the ability to deliver to analog high definition video output may be impacted in the future by the AACS-mandated “analog sunset,”  and possibly other content protection provisions that could limit or disable analog output on HDMI-equipped devices.