Question about Prime Video HDCP detection enabling HD streaming through browser.

[IchigoMait]

When I have a hdmi and a dp displays connected and both are turned on, HD is enabled.
If I turn hdmi monitor off, HD is disabled.
If I unplug the hdmi cable from the graphics card, then HD is enabled. (probably vice versa too, if anyone needs me to test it, I can, but only if anyone wants)
(where the browser is, in terms of on what monitor, doesn't matter).

Found out it has been an issue for years, someone posted somewhere the exact same issue 7+ years ago at some other forum.
Prime Video support was useless, they started only focusing on the prime video app error, ignoring the multimonitor hdcp bug.

So I'm wondering if it's a firefox issue, a browser issue overall, or just how prime video hdcp detection works through the browser.
I'm assuming it could be some sort of failsafe, if it detects you have 2+ monitors connected, but if one of them is turned off and it thinks hdcp is somehow circumvented on it, even though in the nvidia control panel it shows both have hdcp always enabled, it will disable HD as a safety measure or something.

Wanted to try the prime video app, but that gives some error that streaming is unavailable, and microsoft edge also gives the same error as prime video app that comes from microsoft store.

So I'm just for now gonna use black fullscreen through microsoft photo on the hdmi monitor, whenever I use prime video streaming.

[Mizar]

Streaming companies have been trying to push their apps as the defacto way to watch their content so they hinder browser playback on purpose.

The other issue could be that in fact your graphics card doesn't allow HD on both monitors at the same time.

[IchigoMait]

3 points, not 2. You missed the first sentence.
"When I have a hdmi and a dp displays connected and both are turned on, HD is enabled.
If I turn hdmi monitor off, HD is disabled.
If I unplug the hdmi cable from the graphics card, then HD is enabled."

Nothing to do with gpus, the HD in Prime Video is what data is being streamed.
When I say HD that is being used in Prime Video it means like in youtube, 1080p or 4k etc. They don't have resolution options, they use 6-7? data streams in GB per hour or whatever, 3-4 being non HD when HDCP isn't being detected, and the other 3 (Good, Better, Best) is when HD is enabled in the video that is being streamed, HD switches automatically, no need to refresh the page.
The HD is not about allowing to display content on a monitor, it allows it for the stream to be in higher quality. I can drag the browser however I want all over the desktop between multiple monitor, it doesn't impact it.

The detection system to allow HD streaming disables HD streaming, when it detects that 1 hdcp monitor is turned off, but if it's unplugged it works fine, if all monitors are plugged in and turned on it works fine.

So I'm wondering if their own web page has some weird mechanic that disables HD content the moment it detects that any HDCP device is turned off, even if another one is working, or it's a browser quirk. Could be a gpu driver quirk, even though it always shows HDCP enabled for monitors, if you have the right cable and it's plugged into the monitor and gpu, regardless if it is turned off or on.

Also their app doesn't work, so nothing to push. Has the same issue as in microsoft edge, caveat of using microsoft store stuff, broken garbage most of the time. I'm suspecting it could be because I've disabled location tracking in windows, and microsoft stuff use that.

[jscher2000]

Websites can request the browser to provide information about your displays, at least with respect to resolution and color depth. I don't know whether the browser provides other details; perhaps a fingerprinting test site would list what the browser provides.

It's possible that Firefox doesn't provide the correct information in your scenario with the monitor off but cable still connected, or that the graphics card doesn't change the data it sends to Firefox until the cable is disconnected. ??

[IchigoMait]

Wonder if they're using something like this.
https://github.com/WICG/hdcp-detection/blob/main/explainer.md

Also related maybe.
https://github.com/mozilla/standards-positions/issues/243

[IchigoMait]

Tried today again, and now it works. Dunno what the consistency is behind it, before I posted this question, I could just toggle the HD just by turning off 1 monitor. Now it works.
Maybe it depends on which monitor I had the browser last opened, when I opened the browser, and so it remembers only hdcp from 1 monitor at a time.

[IchigoMait]

Tried turning off either monitor. HD still on.
Tried a fresh browser open on either monitor and then bringing it to the other monitor and turning off the monitor where browser was opened, hd still on.

Guess they fixed it, could've been a nvidia driver issue, that I updated also yesterday.
Or it was maybe only on prime video end.

Well whatever it was, if the issue crops up again, will post then.