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#374133 - 27/08/2023 21:49 Macs, HDCP, and related gremlins
DWallach
carpal tunnel

Registered: 30/04/2000
Posts: 3810
The setup: Sony A8G (circa 2019, running an ancient Android 9 system, which Sony doesn't seem to be updating), M1 MacBook Air (circa 2021, running Ventura 13.4.1), no-name Thunderbolt to HDMI adapter.

With a previous Intel Mac, I could plug this all together and everything worked. I'd never bothered trying it with the shiny newer M1 MacBook Air until today. The screen would connect for a few seconds and then disconnect. I tried it in a variety of configurations. Different HDMI cables. Passing through my AV receiver or not. Same problem. Also tried an M2 MacBook Air. Same problem.

Also of note, this TV seems to be too old to speak Apple AirPlay. That means that the TV doesn't show up for any sort of wireless sharing. (Yes, I "authorized" my laptop. This didn't help.)

My workaround was to use the Chrome browser to "cast" the screen. This worked, but it's a kludge, and for some reason it doesn't go full screen. You get a black border around whatever you're casting.

I'm assuming that the root problem here is HDCP shenanigans, but I don't know how to determine this in any definitive way. I've read many, many web pages, and the best advice seems to be buying an HDMI splitter (1 in, 2 out), typically $15 - $25 on Amazon. These apparently filter out all HDCP requests and then things get back to magically working again. Again, this seems like a kludge, and I suspect that it will fail in some important way when I want something that "just works".

The goal:

Once in a while, I like to use my TV as if it's a computer monitor. Maybe that's to show / practice a PowerPoint talk. Maybe I just want to sit on the couch and work on the giant screen as if it was a regular computer monitor.

So, am I missing something or it this fundamentally going to be a pain to resolve?

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#374134 - 28/08/2023 00:12 Re: Macs, HDCP, and related gremlins [Re: DWallach]
DWallach
carpal tunnel

Registered: 30/04/2000
Posts: 3810
Typical thread which supports the theory that Apple has broken something that seems to just work fine on PCs.

https://www.reddit.com/r/VIDEOENGINEERIN...splay_to_video/

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#374135 - 28/08/2023 00:46 Re: Macs, HDCP, and related gremlins [Re: DWallach]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31585
Loc: Seattle, WA
What a coincidence, I've been messing with connecting my MBP to various monitors and TVs lately.

I'm still on an Intel mac (15-inch, 2016) at the moment. I've been poking at different HDMI issues with it. I'm trying to game with it (using CrossOver to run Windows games on the MacOS desktop). I have been finding that I get different results, depending on which USB-C-to-HDMI adapter that I use. Usually it works, but under certain conditions and screen resolutions, depending on which adapter I use, the screen goes black and the monitor (or TV) says "no signal". Or, it works, but, there is some kind of intermittent CPU problem where my mouse response is jittery and the cursor bounces around the screen.

You should try to rule out whether the problem is truly HDCP, or some other funkiness with the adapter. Some adapters are thunderbolt-native devices and others are just USB-C devices. I think (not sure) that the latter require some kind of software driving to occur on the Mac side, causing additional CPU usage. I have been through several adapters and gotten different results with each of them, indicating that the Mac support for each one differs slightly:

- Plugable thunderbolt two-monitor adapter (Amazon) - Certain resolutions cause a black screen "no signal", but, no CPU/mouse issues. If I can program the game to be one of the supported resolutions, this works great.

- Older Anker C-to-HDMI adapter (Amazon) - Works with all resolutions, but, CPU/mouse issues sometimes occur when using.

- Newer Anker C-to-HDMI adapter (Amazon) - Certain resolutions cause a black screen "no signal", and also, I get CPU/mouse issues.

- Via a CalDigit TS4 docking station, Plugable active DisplayPort-to-HDMI adapter (Amazon) - Certain resolutions cause a black screen "no signal", and also, I get CPU/mouse issues.

- Via a CalDigit TS4 docking station, Caldigit active DisplayPort-to-HDMI adapter (Amazon) - Certain resolutions cause a black screen "no signal", and also, I get CPU/mouse issues.

So even without HDCP getting in the way, this stuff can be hard to get working right, and it may be dependent on which adapter you're using.

Footnote: I've heard that the M1/M2 macs can't drive dual monitors off of one thunderbolt cable. (My Intel mac can, no problem). True?
_________________________
Tony Fabris

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#374136 - 28/08/2023 12:11 Re: Macs, HDCP, and related gremlins [Re: DWallach]
DWallach
carpal tunnel

Registered: 30/04/2000
Posts: 3810
Possibly related: one of the classrooms where I teach, on campus, has a fancy Crestron setup, and I had some issues like this. Campus IT added some "disable HDCP" button to the configuration panel and then everything worked.

In my dream of dreams, the computer would provide some feedback about what's happening rather than just flaking. I mean, I could go dig through Console logs, but something user friendly wouldn't hurt.

Dual monitor stuff: I think that's right for the original batch of M1 devices, having some limits on external monitors. I hope, but haven't tested, that everything works better with newer generation machines.

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#374165 - 30/09/2023 23:24 Re: Macs, HDCP, and related gremlins [Re: DWallach]
DWallach
carpal tunnel

Registered: 30/04/2000
Posts: 3810
Update!

(Backstory: I've started a leave of absence from my normal job at Rice, and now I'm working for the U.S. government and I've rented an apartment in Arlington so I'm closer to the action. Still have the place in Houston, flying back and forth, etc.)

So for my new apartment, I got a new TV. i decided to go for a mid-range Sony with the "full array LED" backlight, since it's "good enough" and a whole lot cheaper than OLED. Plus, when my gig is up, and I head back home, this will turn into the backup TV. Or something.

Anyway, I made sure to get the 2023 edition of the TV, just in case that made it slightly less likely to have HDCP gremlins. I connected my Mac to the TV with the built-in HDMI port and... everything "just works" exactly like you'd expect. And, exactly unlike what I had back at home with a slightly older TV and receiver.

So far, it's just the computer and the TV. Coming up, some speakers and a receiver. Hopefully the "everything is relatively new equipment" property will make it more likely that I continue to experience everything "just working".

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#374171 - 05/10/2023 19:49 Re: Macs, HDCP, and related gremlins [Re: DWallach]
jmwking
old hand

Registered: 27/02/2003
Posts: 770
Loc: Washington, DC metro
Welcome to "the DMV"!

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#374184 - 23/10/2023 11:38 Re: Macs, HDCP, and related gremlins [Re: jmwking]
DWallach
carpal tunnel

Registered: 30/04/2000
Posts: 3810
Originally Posted By: jmwking
Welcome to "the DMV"!

Every time I see this, I think "Welcome to the Department of Motor Vehicles", and it's just really weird. The military types seem to use the term "National Capital Region" (or is that "Capitol"? -- suitable digression), which seems ungainly. In my own head, it's all just "the D.C. area", even though that's being fuzzy.

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#374185 - 23/10/2023 18:58 Re: Macs, HDCP, and related gremlins [Re: DWallach]
Tim
veteran

Registered: 25/04/2000
Posts: 1524
Loc: Arizona
We've been using NCR for a bit over a decade I think.

I don't remember the reason for the change, but at least it is unambiguous.

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