This last Sunday, for the first time in 9+ months OBS didn't recognize the 3.5mm audio feed (from sound panel).
Upgrade from 25.0.8 to 26.1.1 a few weeks ago. and I I think I did OEM BIOS/driver updates a few weeks ago as well.
Turns out OBS was configured for Audio Input to use Default device (via Realtek motherboard based port) and for some reason changed this time??? no idea why. Took 20+ minutes of stress right before livestream before I recognized issue was OBS association to Audio device via OS device, and somewhere along that path, something changed.... There are some nice parts of Win10, but at times I really do miss the older, simpler desktop OS versions before it
Not sure the Windows OS privacy settings apply in this case.
That might be the problem.. assuming... not a good idea. Maybe OS privacy/security settings don't apply, but they also easily could.
and Win10 v1904 is a year and a half old... passed time to be updated
Ignoring OBS, does the camera appear in any other software? if not, have you tried a different camera? have you made sure the camera signal didn't get messed up (be that HDMI vs BNC or RCA? or could be a cable issue?) checked with BlackMagic on troubleshooting? Have you tried bypassing the ATEM switcher to troubleshoot? lots of possible kinks in that video path, that may or may not have anything to do with your PC (based on what you described so far.. you may have done more troubleshooting and narrowed issue down to PC and just not mentioned it)... I'm just trying to be thorough and give you a range of things to check
oooh, just looked up that camera.... lots of possible changes on camera itself like CODEC, or ?? could cause mis-match with other settngs
good luck