HDCP stands for High-bandwidth Digital Content Protection.
It’s a copy-protection system used on digital video connections like HDMI and DisplayPort.
HDCP’s job isn’t to improve picture quality.
Its only purpose is to decide whether protected content is allowed to play.
Most of the time, HDCP works quietly in the background.
When it fails, nothing plays.
What HDCP Does
When protected content starts, devices ask a simple question:
“Is every device in this signal path authorized?”
If the answer is yes, playback continues.
If the answer is no, the source blocks the content.
HDCP checks happen between:
- The source
- Any switches, receivers, or extenders
- The display
Every device must support the required HDCP version.
If one device doesn’t, the chain breaks.
Why HDCP Causes Problems
HDCP issues usually appear when protected content meets real-world systems.
Common situations:
- Older TVs or projectors
- HDMI splitters or extenders without HDCP support
- Mixed devices with different HDCP versions
- Long signal chains with multiple devices
Menus and desktops may still work.
The problem only appears when protected content starts playing.
What HDCP Problems Look Like
HDCP failures don’t always show clear error messages.
They often appear as:
- Black screen when playback starts
- Audio with no video
- Video works until a streaming app opens
- Messages like “This content cannot be displayed”
Because basic video may still work, HDCP problems are often mistaken for EDID or cable issues.
What To Do When You See This
First, simplify the signal path:
- Remove unnecessary splitters or converters
- Connect the source directly to the display
Then check compatibility:
- Confirm all devices support the same HDCP version
- Avoid mixing very old and very new equipment
If the issue only happens with protected content, HDCP is likely involved.
Bottom Line
HDCP controls whether content is allowed to play, not how it looks.
EDID decides what signal gets sent.
HDCP decides whether that signal is permitted.
When systems get more complex, HDCP becomes another point of failure.
Understanding it makes many black-screen problems make sense.