Adjust Opacity of an HDMI Source

I have two HDMI sources that I want to overlay on top of each other, and I want to adjust the opacity of the top layer. Is this doable with the Atem Mini Pro?

You could do a manual fade from one source to the other and stop if halfway.

Another solution is to the upstream keyer (linear key) and set the fill source to the second source and the key source to an a gray image in the media player. The grayness of the image determines how transparent the fill source will become when the upstream keyer is enabled.