Problem solved guys I finally make it work sending signal from Mac OS using Monterrey update to Blackmagic Atem hd.
I did got this cheap hdmi splitter scaler 4K to 1080p on Amazon I plugged on Mac and change resolution in Display on General settings,so open display selec
1080p on your second monitor after this we need to change settings on atem hd open switch controller on your computer go to the settings on the left bottom of screen and look for the resolution settings there by default should be on ( 1080i59.64 ) we need to change that resolution, click on up and down arrows to open resolution menu scroll down to look for 1080p 59.64
Select it click Set and click change and now that you have Mac OS with Monterrey using hdmi splitter scaler on 1080p for secon display and Atem receiving 1080p 59.64 should be receiving signal from Mac to your Atem hd.
On bottom I’m sharing the link for the scaler that I bought.
![Image](https://uploads.tapatalk-cdn.com/20211218/849fd9d78b393530548214531a823133.jpg)
If more details need it feel free to ask next time may post pictures. Have a great day everyone.
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