UK What HDCP does
HDCP, or High-bandwidth Digital Content Protection, is a copy protection system that encrypts digital video as it travels from a source, such as a computer, media player or set-top box, to a display. Intel developed it in 2000, and it is licensed by Digital Content Protection LLC, an Intel subsidiary.
The aim is to stop films, broadcast TV and other licensed content from being recorded as a perfect digital copy on its way to the screen. HDCP runs on HDMI, DisplayPort and DVI, and on extension systems such as HDBaseT. A source only sends protected content once every device in the chain has proved it is a licensed HDCP device that will not pass the content on unprotected.
HDCP is applied by the source, and only when the content requires it. A computer’s desktop, an industrial camera or a medical imaging system usually sends unencrypted video, while a streaming app, a Blu-ray player or a pay-TV box switches HDCP on.
How HDCP works
Each HDCP connection goes through the same three steps whenever a cable is plugged in, a device wakes up or the input is switched.
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Authentication. The source and the display, or the next device in the chain, exchange keys issued by the licensing body and check that each is genuine.
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Encryption. Once authenticated, the source encrypts the video and audio. The display decrypts it just before showing it, so the signal on the cable is unreadable to anything in between.
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Revocation and repeaters. Sources can block devices whose keys have been compromised. Splitters, switches and extenders act as repeaters: they must authenticate too, and report every display connected behind them.
What HDCP does not do
HDCP has no effect on picture quality: once decrypted, the pixels are identical to an unprotected signal. It adds no noticeable delay during playback, although the handshake can add a second or two when an input is switched or a display wakes. It also does nothing for cyber security, because it protects content owners rather than the data in your system.
HDCP versions compared
HDCP has two families. Version 1.x was tied to DVI and HDMI, while version 2.x was redesigned to work over any interface and is required for most 4K content.
| Version | Year | Typical use | Notes |
|---|---|---|---|
| HDCP 1.x (1.4 most common) | 2000 to 2009 | HD and 1080p content | Supported by almost every HDMI, DVI and DisplayPort device |
| HDCP 2.0 and 2.1 | 2008 to 2013 | Wireless and early interface-independent links | Superseded by 2.2 |
| HDCP 2.2 | 2013 | 4K UHD streaming, UHD Blu-ray, pay TV | Needed on every device in a 4K chain |
| HDCP 2.3 | 2018 | 4K and 8K content | Security update; plays HDCP 2.2 content |
Version 2.x devices usually support 1.4 as well, so older HD content still plays. The reverse does not hold: a display or splitter that only supports HDCP 1.4 cannot show content protected at 2.2, even if it can display a 4K signal. When planning a 4K chain, check the HDCP version on every input and output, not only on the source and the screen.
What causes an HDCP error
An HDCP error appears as a blank or black screen, a message such as “HDCP unauthorised”, or video that plays while the protected content stays dark. It almost always means one link in the chain failed to authenticate.
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A device that does not support the version needed. Typically an older monitor, projector, splitter or extender in a 4K chain that supports only HDCP 1.4.
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Too many displays. Each repeater has a limit on how many downstream devices it can authenticate, so large splitter arrays can fail.
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A dropped handshake. Long or poor-quality cables, or devices powered on in the wrong order, can interrupt authentication. Unplugging and reconnecting, or power-cycling the display first and the source last, often clears it.
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A capture device or recorder. Licensed capture hardware refuses HDCP-protected input by design, so the capture shows black or an error.
HDCP in industrial and professional video
Most industrial video sources never switch HDCP on, so most systems never meet it. It matters in three situations. First, in video capture: our HDMI capture cards record cameras, medical equipment, instruments and computer outputs, but like all licensed capture devices they cannot record HDCP-encrypted streams, so the source must send unprotected video.
Second, in signage and public displays: a digital signage player showing licensed 4K content needs HDCP 2.2 on every link to the screen. Third, in long cable runs: video extenders, switches and splitters must pass HDCP at the version the content needs, or the far screen goes blank. Check the HDCP version per input on the datasheets of the industrial monitors in the chain, too.
Quick answers on HDCP
HDCP: common questions
What does HDCP stand for?
High-bandwidth Digital Content Protection. It is the copy protection system used on HDMI, DisplayPort and DVI links.
What is HDCP 2.2?
The version required for most 4K content. Published in 2013, it is needed on every device between a 4K source and the screen, including splitters and extenders.
What is the difference between HDCP 2.2 and 2.3?
Mainly security. HDCP 2.3 strengthens the protocol and plays all HDCP 2.2 content, so a 2.3 device works wherever 2.2 is required.
Does the HDMI cable need to support HDCP?
No. HDCP is handled by the devices at each end. A cable only matters if it is too long or poor enough to make the handshake drop.
How do you fix an HDCP error?
Find the link that does not support the version needed. Connect the source directly to the display to test, then add splitters or extenders back one at a time, and update firmware where available.
We check the HDCP behaviour of the sources, extenders, capture cards and displays in each system we supply, and test the full chain before it ships as standard.