It’s a credit to engineers and designers that home theater systems don’t break more often than they do. Just the TV you’re watching is an incredible confluence of panel, circuit, and software design, let alone a game console or a Blu-ray player. And all of these electronics have to work together in harmony, or else your game or movie just won’t show.
A few components are more likely to break this harmony than others. One of these is HDCP, which some of you may be all too familiar with. If you’re not, here’s a quick primer, and what you need to do if its ugly side manifests.
What is HDCP, and what makes it so thorny?
A solution to someone else’s problem
HDCP is short for High-bandwidth Digital Content Protection. It was developed by Intel, and initially deployed for DVI ports and cables in 2000. It didn’t make its way to TVs until 2003, when it was integrated into the HDMI standard. It would later show up in DisplayPort as well, but for our purposes, HDMI is all that matters.
As the acronym suggests, the goal of HDCP is to reduce piracy. Before data is transmitted, a sending device performs an authorization check with the receiving device(s). If everything along the chain is authorized, content is encrypted before broadcast to prevent interception. Colloquially, this whole process is known as an HDCP handshake.
There are a few ways a handshake can fail, one being version compatibility. HDCP 2.2 is the minimum for 4K HDR, and the latest release is actually 2.3. If you’re trying to play content that requires a particular HDCP spec, every component in an input chain needs to support that version or later. If there’s a version mismatch, you’ll likely encounter an error message or a plain black screen, much to the confusion of us ordinary consumers. Under particular circumstances, you might see your content, but at a degraded quality level.
There can also be flaws with the way HDCP handles encryption. Devices may be running outdated firmware, for instance, or have a limit on the number of keys they can generate. A degraded or mistimed signal might also be enough to cause chaos, as there are firm windows on how long a handshake can take.
The irony of all of this is that in the real world, HDCP is useless as an anti-piracy weapon. Hackers and others have repeatedly found ways to bypass it, and of course there’s no need to rip from an HDMI or DisplayPort feed if you can directly crack a disc or file’s native copy protection. Arguably, HDCP has been reduced to a placebo that apparently makes some industry executives happy, but doesn’t help you or filmmakers.
How can you fix HDCP handshake errors?
A few common tactics
You may want to verify the HDCP versions on all relevant devices, including your TV, cables, receiver, and/or other connected peripherals. If you don’t have manuals handy, a few web searches for model names will likely do the trick. Should you discover something is limited to HDCP 2.2 or earlier, consider swapping it out — because even the 2.3 standard dates back to 2018.
Next, be sure all of your devices are running the latest available firmware or drivers. Most software updates won’t affect HDMI, and you can’t upgrade HDCP versions this way. But since bugs do impact handshakes occasionally, it’s crazy not to rule this out.
When compatibility and software complications don’t seem to be at play, one common trick is to unplug the power for everything in the affected input chain, wait at least 30 seconds, then plug those devices back in one-by-one. One last ditch option is to try to simplify that chain. If you can plug your Blu-ray player directly into your TV instead of a receiver, you’ve actually eliminated three potential failure points — the receiver plus two HDMI cables.
