Hope someone can help me figure out what's wrong. I own a Galaxy S10 and I tested an HDMI adapter to channel the output to my TV. It works very well, both for Samsung Dex and for screen mirroring. I am now trying to capture my phone's screen using HDMI ouput with a video capture card on my computer (Blackmagic Intensity Pro 4K).
It's working fine when using Samsung Dex. When I switch to screen mirroring, however, the capture card doesn't seem to be able to retrieve a signal or the card can't decode it. The monitor goes black.
It's the same for Media Express, the software that comes with the capture card, and with Open Broadcast Studio. That's why I assume the HDMI signal might be different - although both should be 1080p60 (8bit BGRA).
I tried to change the phone's screen resolution, but that didn't seem to change anything. I tried opening an app and rotating the phone into landscape mode. No effect.
What might be different with the HDMI signal and how could I make it work?