4k streaming not working on external display (possible HDCP Issue)

If you play videos on platforms like Netflix, Amazon Prime or Disney+ they require HDCP 2.2 to protect their content if you want to stream in 4k resolution.

Problem:

If you connect an external display to a MacBook the HDCP protection does not work like expected - therefore you can not play 4k content on external displays. Multiple people I know (including myself) have this problem.

You can tell it's not 4k by looking at the labels on the Netflix website:

Integrated Display (Dolby Vision/UHD-Logo):

External Display (HD-Logo):

Netflix says in their FAQ that you should use Safari, so that is what I used.

If you move the window to another display and refresh the page, the logo changes to show which max resolution is supported.

You can also check your HDCP status in Chrome via: https://googlechrome.github.io/samples/hdcp-detection/

I have tested this with:

• Netflix (Subscription with 4k included)
• MacBook Pro M2 Max and MacBook Pro M3 Max
• 2 ASUS Displays, 1 Acer Display, 2 LG Displays (all with support for HDMI 2.0, HDCP 2.2 or HDCP 2.3 and DisplayPort 1.4) - only one display connected at once

I also tested multiple connections:

• multiple HDMI 2.0 cables directly connected to the HDMI port of the MBPs
• USB-C to DP 1.4 Cables with HDCP 2.3 capability
• a thunderbolt dock with DP and HDMI

With my windows pc everything works fine. Only the MacBooks do not work as expected.

Several friends of mine tested their displays/MacBooks with Amazon Prime and Disney+ and can also not watch 4k content.

I think the HDCP 2.2 implementation in MacOS might be too strict or faulty.