Rendering video with Alpha renders transparent content as black 23.04.0

Hello fine commnity!
I am trying to render an intro clip filled with effect to reuse it later (OBS and as transitions in kdenlive videos)

I am certain that my layers are transparent as I can put an image under them in kdenlive before rendering and it will show through.

Once rendered (VP9 webm) the transparency is gone…

I read for 2 hours online about setting black_track producer to #00000000 but this part does not appear in the .mlt script and I read it was an old setting that does not exist anymore.

I really need my render to have transparency… keying it out is janky! Does someone know how to achieve it?

P.S.: I tried with a simple title clip and image and had the same issue as with my bigger project.

OS: Pop!OS 22.04
PC: Lenovo t14 AMD with Renoir GPU, Default drivers
Kdenlive: 23.04.3, from the apt repo (aka, not Flatpak)

Of course, as all things work in life, I found it 30 seconds later…
SO, the issue is the same as it always been… The track is not correctly set as transparent… the syntax of the xml has changed from older versions though…
Leaving it here for prosperity:

Tried to post a detailed procedure with screenshots, but the forum won’t let me as I am a new user :frowning:
I will post later… When I get all the bells and whistles of a real account!
Please remember I tried contributing!

In the render window: Do you have tried one of the “Video with Alpha” settings? Alpha MOV, Alpha VP8, Alpha VP9 and Ut Video.

I did, turns-out the issue was the good old black channel being incorrectly set in KDEnlive mlt profilers…

I changed a value to #00000000 and it fixed it…

Once I reach level 1 in reputation on this forum I will post my complete fix… for now I can’t (I kept a copy in an .md editor of my own)