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AdriftAtlas

macrumors member
Original poster
Oct 27, 2016
87
72
Whenever my two Dell U2718Q 4K@60hz monitors are hooked up via DP HDCP stops working. Nearly every streaming app and/or Safari shows a black screen, throws an HDCP error, or downgrades from UHD to HD. I've tried hooking up only one monitor via HDMI and the same thing happens. HDCP only works when no external monitor is hooked up.

HDCP test for Chrome:

https://googlechrome.github.io/samples/hdcp-detection/

I am running macOS 13.1 on a MBP 16" M1 Max. Does anyone have working HDCP on external monitors? Anyone know how to fix this?
 

EugW

macrumors G5
Jun 18, 2017
14,980
12,943
Whenever my two Dell U2718Q 4K@60hz monitors are hooked up via DP HDCP stops working. Nearly every streaming app and/or Safari shows a black screen, throws an HDCP error, or downgrades from UHD to HD. I've tried hooking up only one monitor via HDMI and the same thing happens. HDCP only works when no external monitor is hooked up.

HDCP test for Chrome:

https://googlechrome.github.io/samples/hdcp-detection/

I am running macOS 13.1 on a MBP 16" M1 Max. Does anyone have working HDCP on external monitors? Anyone know how to fix this?
I guess you mean HDCP 2.2, because to get HD would usually mean you’re getting HDCP 1.4.

Anyhow, this is interesting.

With my M1 Mac mini and my 30” Apple Cinema HD Display connected through a Club 3D USB-C DL-DVI adapter, HDCP doesn’t work for HD. It works from my m3 MacBook.

With my M1 Mac mini and my 4K 28” Huawei MateView, HDCP for HD works but HDCP 2.2 for UHD does not. I assumed it was just because the monitor doesn’t support HDCP 2.2, but perhaps it’s an Apple Silicon glitch. I tried both USB-C and HDMI. (Huawei doesn’t list an HDCP version spec on their monitor spec page.)

EDIT:

I plugged my Apple TV 4K (2017) into my Huawei MateView, and I get 4K streaming just fine. So, it's a compatibility issue with the M1 Mac mini.
 
Last edited:

JPack

macrumors G5
Mar 27, 2017
13,568
26,266
Many of newer Dell monitors get a firmware update to work with M1. Given yours is from 2018, it might be too old.
 

EugW

macrumors G5
Jun 18, 2017
14,980
12,943
I'm not sure how useful that test is.

It says my 2017 iMac supports HDCP 2.2 in Chrome. However, I can't stream any DRM'd 4K content on it in Chrome. It only works in HD.
For the 2017 iMac with Safari, the test seems to fail. It says "NotSupportedError: The operation is not supported." However, in Safari, I can stream DRM'd HD content just fine (but not in 4K).

For my M1 Mac mini with MateView 28 in Chrome, it says "output-restricted", for all versions of HDCP, but I can stream DRM'd HD content just fine (but not in 4K).
For my M1 Mac mini in Safari, it says "NotSupportedError: The operation is not supported." However, in Safari, I can stream DRM'd HD content just fine (but not in 4K).
 

IncreasinglyFrustrated

macrumors member
Sep 22, 2020
37
94
Two things:

1. Try creating a free account on Peacock to test video playback. They stream all UHD content in HLS/CBC (an Apple-specific packaging profile). It's the only service I could use while I was trying to work through the same issue.

2. My M1 Mini refused to work with my receiver & 4K TV; (black screens & HDCP errors on all services other than Peacock). I had to buy one of these gizmos to work around the issue, and connect it inline before the receiver: https://www.amazon.com/gp/product/B004F9LVXC

Note for #2: I swapped all my HDMI cables for ones with 2.1 compatibility while trying to find a solution. I'm not sure if that ended up being part of the fix or not.
 
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AdriftAtlas

macrumors member
Original poster
Oct 27, 2016
87
72
I hooked my LG C7 TV up to my MBP via its native HDMI port using the same cable and input my Apple TV 4K uses. The Google Chrome thing said output restricted for all versions. Netflix would only play in 1080p on Safari.

Something is obviously bugged as it doesn't matter what is hooked up externally, it all breaks HDCP.

Does anyone know if there is some HDCP diagnostics in macOS?
 
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AdriftAtlas

macrumors member
Original poster
Oct 27, 2016
87
72
Also, I am not using DisplayLink, all connections are native TB4 or HDMI. Here are the cables I am using:
 

Zest28

macrumors 68030
Jul 11, 2022
2,588
3,953
Not sure if HDCP applies to Youtube, but I have been able to stream 8K HDR @ 60hz on an external display from Youtube on my 16" M1 Max MacBook Pro.
 

EugW

macrumors G5
Jun 18, 2017
14,980
12,943
Not sure if HDCP applies to Youtube, but I have been able to stream 8K HDR @ 60hz on an external display from Youtube on my 16" M1 Max MacBook Pro.
HDCP is not required for that.
 

AdriftAtlas

macrumors member
Original poster
Oct 27, 2016
87
72
The issue was the Cable Matters USB-C to DP 1.4 cables that I was using. Replaced the cable with a VESA certified one and it works:

The Google HDCP test does not seem to be accurate. A reliable test is to open a 4K Netflix title in Safari and check the debug text (Cmd+Option+Shift+D) for 2160 resolution being "usable" and not "output-restricted" on the "KeyStatus" line.
 

AdriftAtlas

macrumors member
Original poster
Oct 27, 2016
87
72
I retested the Cable Matters cables again. I got Netflix 2160 - usable. Appears that HDCP is simply temperamental. The monitors and/or MBP could also be causing issues. Sleeping my MBP and then waking it up with both monitors attached improves the chances of HDCP working correctly. HDCP is simply a mess of a technology...
 

macmus12

macrumors regular
Jul 14, 2022
178
46
I retested the Cable Matters cables again. I got Netflix 2160 - usable. Appears that HDCP is simply temperamental. The monitors and/or MBP could also be causing issues. Sleeping my MBP and then waking it up with both monitors attached improves the chances of HDCP working correctly. HDCP is simply a mess of a technology...
I would say apple implementation is a mess. It works on PC with single graphic card no matter what u do.
 
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