I've been using some $oftware to make Alpha Transparent videos for ages, but now I want to be able to do that in Kdenlive. I'm very interested in using Webm Alpha Transparency capable encoder.

I've tested conversion of my alpha transparency videos with RGBA format converting these videos in ffmpeg and then overlay them in Chrome Browser, so I know webm can handle transparency.

I've been testing Kdenlive with some effects like affine, blue screen, alphaatop which should generate transparency, but none of these will get me a alpha transparent video in Webm render output. They're black backgroung videos.

Anyone knows a profile command that would generate such RGBA webm file, like a command in kdenlive webm render profiles?

Any help would be appreciated.