HDCP

showstack / protocols / hdcp

Also called High-bandwidth Digital Content Protection.

Content protection negotiated between every device in a video path. Each hop authenticates the next, so the chain is only as capable as its weakest link — and when it fails, the symptom is a black screen at the far end rather than an error where the problem is.

Video controlProprietaryDigital Content Protection LLCReported

Not a traffic flow

An encryption and authentication scheme wrapped around a media link, not a flow beside it.

What goes wrong

One non-compliant device anywhere in the path breaks the whole chain, and the failure appears at the display rather than at the offending box.

Version matters. A source insisting on HDCP 2.2 or 2.3 will not fall back to an older sink in every case, and the result is again a black screen.

Repeater counts are limited. Long chains of switchers and splitters can exceed the permitted depth even when every device is compliant.

Content that does not need protection can still fail if a source enables HDCP by default. Turning it off at the source is often the fix.

Typical use

Any path carrying commercial content from a consumer source
Negotiated automatically by HDMI, DisplayPort and HDBaseT devices

Sources

HDCP Specifications — Digital Content Protection LLC primary

Understand the mechanism

Why the picture is black

Something wrong, or missing?

Known gaps on this entry: default_ports, first_published, implementations. If you can source one of them, that is a ten minute pull request.

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