TESmart 8x8 HDMI matrix switcher to Mini Extreme: no signal

I have an Atem Mini Extreme ISO set up in a portable studio rig, and was looking to boost flexibility by adding an 8x8 HDMI matrix switcher (TESmart HMA0808A30). The problem: signals from the matrix to the Atem are not picked up at all. No signal is detected on any of the input ports.

What works:

• laptop > matrix > monitor
• camera > matrix > monitor
• Atem > matrix > monitor

What does not work:

• laptop > matrix > Atem
• camera > matrix > Atem

Unfortunately the matrix switch does not have any options that I can set. What I have tried without success:

• setting different refresh rates at the source (laptop, camera)
• using a UpDownCross converter (laptop > UDC (hdmi in to hdmi out) > Atem).
• putting a 7" field monitor in the middle: I get an image on the monitor, but not on the Atem (laptop > matrix > field monitor [OK signal] > Atem [no signal])
• Setting the Atem to fixed refresh rates

Things I have considered:

• buy a different HDMI switcher that allows for troubleshooting & customization (e.g. Aten VM0808HA), price is 2,5x of the TESmart switch though
• Adding HDMI splitters might resolve the issue (according to several YouTube sources), but I am not to keen on adding 6 of those (both from a cost and a space perspective)
• Adding an EDID solution like the HDfury dr HDMI boxes

Adding a Smart Videohub and all the associated hdmi<>sdi conversions would be cost-prohibitive for us, since we only rarely need the flexibility the 8x8 would give us.

Do the laptop or camera work when directly connected to the Atem?

What resolutions do the laptop/camera think they are outputting when connected to the Atem / connected to the Matrix.

Have you tried a different output port from the matrix - many pass the EDID information to source devices from only a single output port - which would then be used by the sources to configure their output.

Could it be that the Matrix is doing HDCP encryption keys. Which basically kills any option to run it with Broadcast hardware as BMD is not allowed to convert or ingest any HDMI signal that had HDCP keying enabled.

Do the laptop or camera work when directly connected to the Atem?

Yes, they do, even at various framerates/refresh rates (24, 25, 30, 60)

What resolutions do the laptop/camera think they are outputting when connected to the Atem / connected to the Matrix.

I have tried a lot of different combinations on the laptops (both PC and Mac), and the cameras have been fixed at 1080p, again, various framerates.

Have you tried a different output port from the matrix - many pass the EDID information to source devices from only a single output port - which would then be used by the sources to configure their output.

I have tried several, but can definitely experiment further here. I know that the PC "sees" the resolution of the first output port it is being switched to, and re-negotiates if the matrix switches from no output ports to a single output port.

Could it be that the Matrix is doing HDCP encryption keys. Which basically kills any option to run it with Broadcast hardware as BMD is not allowed to convert or ingest any HDMI signal that had HDCP keying enabled.

It does not sound likely, but I do not know. Is there a way I can check if the matrix switcher adds HDCP?

I do know that if I plug a cable from the matrix that is actively showing a source into the Atem, the source shows up for less than a second on the multiview, and then seems to "minimize" to the upper left corner of the screen, making me believe this is a bug of sorts.

I can borrow some Decimator devices (MD-LX and MD-HX); some people have reported success with those in the signal path between matrix and Atem, will report back.

Also forgot to mention before: output from the Atem back to the matrix switcher works absolutely fine.