Ah that’s a bummer, thanks (Claude lol) for trying. But really appreciate you bringing 3D ti to CE-NO, 
I can’t use CoreElec to watch 3D movies but I have other options which I use. But I still follow your work and I would like to say thank you 
I just received my AM9Pro and guess what? 3D MVC playback might still be possible.
At least 3D displays get recognized correctly and framepacked output works. But the output is buggy as hell, too slow and with bad synchronization problems. I’ll try to identify and fix the issues with my good old friend Claude. 
It’s fun to ride a dead horse. 
Nobody said MVC is not working with AM9, only not with S928X.
But frame packaging mode is not available anymore since Hdmitx21 devices.
Only SBS or TAB.
That’s not totally true. Framepacking mode is available with a capable display connected. The display switches to 3D when I play a 3D MVC file, but the output is faulty with framesync artifacts and it’s too slow. I still don’t know whether or not this is fixable, but I’m trying to at least find the root cause together with Claude.
Ok, then I don’t know AML code…
I don’t want to argue.
I just installed CE on the box and was happy that 3d fp output was available, not so that the output is garbage. You certainly are right, my test proved that fp is broken. I don’t know whether this is fixable without Amlogic, but at least I like to try with my prompting “knowledge”.
NO 3D MVC (hardware based), works just fine with S905X4 device, no replay issues. So if you get replay issues now it seems, maybe 3D MVC isn’t really supported for your device (not at this moment at least).
S905X4 is not hdmitx21, it’s hdmitx20.
Only devices with hdmitx21 are affected by 3D FP limit issue. S928X does not have a MVC hw decoder at all.
That is why I wrote, 3D MVC can work just fine with NO, when a device really supports it. As a response to embo 
Why? Any device up to hdmitx20 on Amlogic-no just support every 3D mode!
It’s only limited by hdmitx21 hardware.
I know we’re in the developer section here.
I was just curious what’s possible regarding 3d with the am9pro and it’s fine that it doesn’t work currently. I still have my AM6B+ if I want stable 3D playback.
Is this a hardware limitaton of the HDMI chip or is it potentially fixable on the driver side? I’ll stop researching if it’s hardware related and try to fix TAB od SBS output of MVC videos instead.
SBS and TAB just works on any NO hardware.
Maybe FP will never work:
[ 0.802477] [hdmitx:] warn getting FEAT_DISABLE_HDMI_TX_3D: 101
[ 0.802490] [hdmitx:] warn getting FEAT_DISABLE_HDMITX: 101
Thanks for the hint, appreciated. I didn’t notice that before.
Yeehaa, run my zombie pony, run!
Claude found the rather simple fix for S6 3DFP output.
The pixel clock needs to be doubled for 3dfp output in the hdmitx21 driver, and the timing tables for 3dfp output have to ported from hdmitx20 to hdmitx21. It works like a charm with my Ugoos AM9 Pro. I’ll create a PR.
I checked it once in the past but missed this part.
I will check it next week.
Thanks for the PR.
My first test display, an Xgimi beamer seems to be very relaxed about missing or wrong HDMI info frames which made it work with only the timing changes.
While I was testing with my LG 3D TV, I realized that it didn’t switch to 3D with any input format. I’ve added two more patches to the PR, one fixes TAB/SBS modeswitching and the other one takes care of FP. Now 3D works on three tested displays with the four commits of my PR.
Which XGIMI beamer? I have a Titan Noir Max and 3D didn’t trigger in the test I did here. Looking forward to re-testing when this makes it into the nightlies. Thanks for giving renewed life to 3D… the format that refuses to die 
! Thanks to @popcornmix, there’s 3D support now as well on RPi4 & 5.
Apologies for the late reaction, I’m just back from my holidays.
Thanks for simplifying my PR. Your commits work perfectly here with all three displays.