Is there something special about input #1 of ATEM mini?

We have 2 identical PTZOptics cameras connected to an ATEM mini. One of the cameras is a direct HDMI cable, the other runs through an Extron DPT HDMI 230 Rx/Tx (HDMI over CAT5).

Both cameras work find on ATEM inputs 2, 3, and 4. But the Extron connected camera does not work on input number 1. The ATEM just shows black screen for input 1 when connected to that camera. I can move that camera to any other input and it works fine, but on input 1 shows black. When I connect the direct HDMI camera to input 1 it works.

Any idea what could cause this? It will be a show stopper when we install our cameras permanently and run them all via Extron HTMI extenders.

The only public documented difference about input 1 is that it's the input used to determine system resolution and frame rate if the system is set to automatically determine that setting. This of course is within the limits of resolution and frame rate of the ATEM Mini itself.

Beyond this, HDMI as a protocol can be finicky overall and if available can often be circumvented by converting an incompatible HDMI signal to SDI, then back to HDMI using a Blackmagic Mini or Micro Converter. I know its kind of a pain but hopefully, considering you're using a 4 input switcher, this issue/solution doesn't quantify very large.

Curiously input 1 on ours is happy with 1080p60 down 12.5m HDMI cables from any of our HDMI cameras.

Inputs 2/3/4 don't work with same cameras (FS100) and cables.

So yes - Input 1 does seem different.....

Note: we manually set the ATEM standard (old habits die hard).

If we place any HDMI device with a through signal such as a splitter or a Matrix before the ATEM all 4 inputs work fine.

I checked on our ATEM TVS HD - none of the 12.5m cables work directly from a camera but do via a Matrix.

The same cables work fine 1080i/720p with any input - not ideal but at least usable until we settle on a brand of fiber cables.

Our cameras have SDI outputs, I am considering running SDI cable (instead of CAT5) and using a BM SDI-to-HDMI right before the ATEM mini input. But I worry that not knowing the cause of this problem, I don't know if that will solve it, and 75 feet of SDI cable plus the converter is a bit to put out on a hunch...

SDI much better if that's an option for you.

It has been noted on numerous other threads on this forum that input #1 only supports YUV signals while the other three inputs support both YUV and RGB signals.

By "YUV" do you mean YCbCr? YUV is an analog color specification, I don't think it would flow over HDMI?

According to the Extron specs, this extender supports both RGB and YCbCr color signals.

Yes, YCbCr....
Cheers

MitchellNeth and Frank Engel gave some super useful info. To add:
Input #1 also is also the input for "camera 1 direct" output mode.

So, 3 things that indeed make input #1 special somehow.

markmc while the Extron may support both YCbCr and RGB, it doesn't mean it automatically sends out what the ATEM happens to like... It may well be the cause, see if you can configure it. Either way SDI with converter will really be better.

By "YUV" do you mean YCbCr? YUV is an analog color specification, I don't think it would flow over HDMI?

According to the Extron specs, this extender supports both RGB and YCbCr color signals.

Yes, YCbCr, thanks - not sure where my brain was when I typed that.

Best guess is the extender does nothing to convert the HDMI data, it is probably just forwarding whatever it gets from the source device.