Actually I think I may have solved it, albeit I would definitely appreciate if anyone else has an easier method!
I found that Mediacoder can convert the Y4M output to a usable format, I then use keylight in after effects to basically key out the blue background, just like a green screen. It's definitely functional, but yeah - if anyone has a way to export with an alpha channel background that doesn't require converting...that'd be amazing :D
After so many years, no one has found a way to display video with the alpha channel? Maybe there are craftsmen who have done this trick? Yes, there are options, as you can withdraw: 1 use a ground green / blue texture 2 just turn off the ground But if you display the animation of units with translucent effects, then neither green nor blue background will not help. Would love to find a solution! Help us! Thanks in advance to everyone for any advice!