In many ways, HDMI has proven to be a wonder drug, providing a superb conduit for high-quality picture, sound, control capabilities, return path for audio and Ethernet connectivity.
In other ways, HDMI can also be a vexing problem for installers.
When HDMI was first designed, it was thought to be a useful one source to one display type of connection. The connection would be a short one, and wouldn’t it be neat to have some sort of command structure built into the format so that inputs would switch when devices were activated? Since the quality was better than what other consumer level video connection types could offer, encryption was built in to prevent folks from copying a program to another device.
Common HDMI Problems
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Those design byproducts and considerations can present hurdles to installers trying to distribute HDMI signals to multiple displays in a commercial installation. HDMI needs to go through an electronic device identification process quite frequently when it is deployed.
Part of the process involves an exchange between the source and the display using an electronic key; source manufacturers can provide lots of keys potentially, but most devices don’t support multiple key sets. This becomes a problem when trying to drive multiple displays with a single source; essentially, when there are only a finite number of keys in the source that source can only drive a finite number of displays.
Related: Challenges of HDMI Installs
Here are some common HDMI trip-ups and solutions for each.
Trip-Up: Multiple Displays
Tip: If your installation potentially involves multiple displays, bypass the distribution amplifier and connect your source directly to the display. If the picture appears satisfactorily, you may have a shortage of keys. There are distribution amplifiers on the market that allow you to emulate keys, so that a single keyed device will display on multiple screens.
Unfortunately, most manufacturers don’t publish a key count for sources.
Trip-Up: Long Distances
Tip: Larger installations tend to involve display devices located some distance from the source. Many industry experts suggest that any distance over 5 meters is potentially troublesome for maintaining required connectivity due to the intricate nature of an HDMI signal. One solution is to deploy conversion boxes – also known as baluns – at either end of the wire run. Baluns commonly require two Cat 5e or 6 wires (four pair per wire) to operate, although single category devices are now appearing on the marketplace, albeit at a premium price.
HDMI is a complex and ever-evolving technology that is at the heart of today’s digital entertainment.