is there any option or parameter to know that a movie is playing?

another question, [pix_movie] doens't need the [pix_texture], and [pix_film] needs, but they seem to do the same.. when should I use one and another?

use pix_film when you need to use other pix_ obects to process the video on the CPU before uploading to the GPU with pix_texture, otherwise pix_movie will work fine.