Movie Sprites

[monsterjam1881]

Heyo community. First I'd like to announce that I finally know how to mask a movie sprite. But... there is a but... I only know how to mask still animations such as eyes blinking, maybe mouth motion and what I came here to ask for is how to created the mask for a movie sprite. Well I can already make a still mask but what if I wanted, say like a hair piece, what if I wanted to make a mask for it. Okok wait so basically, I can create a STLL sprite mask for movie sprites but I'm not sure on how to create sprite masks which move for example, the whole body of a character moving. Here is the example viewtopic.php?t=36951
There is a colour movie, which I already have, and then there is a mask movie. LIKE HOW?? anyways for those who are wondering how I do create my sprite masks, basically, I use Adobe After Effects and drag in the mp4 video. In the link above, It shows that the color movie is white, but mine is black. It's ok that it's black because the mask movie is what matters. So then I paint over the video with white paint and export it. I then use some online video file converter to convert it into webm. I then go to script and define the movie sprite with:

image shin movie = Movie(play="shin(1).webm", mask="shinmaskb.webm")

use show to show the movie as an image and launch game. Great, it works. But like what if I want an animated mask, say like I wanted the one shown in the link above. How does one make one. Anyways sorry for my whole ramble about movie sprites and masks. This has gotten me confused for like 2 days.