HI everybody, thanks to all, i solved the issue. But is still not clear to me what's happening. I mixed the different suggestions you gave me (cause independently no one was working) and i got this:
[gemhead] | [pix_film]/[colorspace RGB( | [pix_alpha] | [colorRGB] | [alpha] | [pix_texture] | [rectangle]
it looks a bit weird but it's working and my cpu is drinking a coffee while i mix four videos of 160/200mb each. but I'm really keen to understand where was my problem... as Philippe said i have to send the [colorspace RGB( message first and then load videos. [pix_alpha] seems to be the obj making the work done, but anyway i had to add [colorRGB] to be able to change transparency. @IOhannes: i'm on windows xp pro. do you think it could be because of this? what do you mean with video-importer? thanks..
Marco