For all help and discussion relating to visual effects in programs that are not already covered in an existing forum, such as Blender, Particle Illusion, etc., along with discussion about effects theories and techniques.
I belive u can do it in Premiere or After Effect's.But i'm not really familiar with the software so u might have to experiment with some text/screen movment/keyframes
If the subtitles you're doing are softsubs and you want to mux the .ass in an .mkv, then make the karaoke effects in aegisub. Doing them with premiere/after effects/whatever else will actually result in a hardsubbed karaoke, which you might not want, though I'm not sure of what you're trying to do.
I suppose that link I found will help in what I'm trying to do. But then again, I have another problem... Following the idea of that link, could anyone tell me if it is possible to have 2 grayscale images on the same frame, at the same time? And if the answer is "yes", how would be the options for the Track Matte effect?
As if, you want the track matte to work on the combination of the two images together? You can nest them in a composition and then use that composition for the track matte.