There’s a wide variety of ways that one can try to make direct correspondences between 2D or 3D visual images and sound. (Any process that represents data as sound falls in the general category of “sonification”.) Here’s an example.
When you open a movie file in jit.movie with a read message, the exact amount of time that that operation will take is unknowable, but jit.movie will send a read message out of its right outlet when the file-opening operation has been completed. When you read in a file, you should generally wait for that message to come out before proceeding. In that message, the word read is followed by the name of the file, followed by a success indicator, 1 or 0.
To show four videos at once in four quadrants of the screen (i.e., four quadrants of a window), one way is to use the videos as textures on four different jit.gl.videoplane objects that are positioned appropriately in GL space.
The line object sends out a periodic series of numbers that progress to some new value over a certain amount of time. The input to line is a destination value (where it should eventually arrive), a transition time (how long it should take to get there), and a time interval between outputs (how often it should send out intermediate values along the way). The left part of this patch shows the use of line to generate integers that are used as pitches.
This is a program for random editing of a video by periodically leaping to randomly-chosen times in the video and playing from there. The jit.qt.movie object here has its attributes initialized such that: a) it will adapt the dimensions of its matrix based on the dimensions of the movie that is read in, b) it will not automatically start, c) it will not loop, and d) it will only send out new frames of video without repeating a frame.
To do animation in 3D, you need to learn about the jit.gl.* family of Jitter objects. To animate MIDI notes as 3D objects, you’ll need to decide what aspect of the note data you want to map to what aspect of the 3D objects. Here's about the simplest possible patch one could make for visualizing a MIDI note; the pitch of the most recently played note is used to determine the horizontal location of a sphere.
The jit.qt.movie object can open (read) a .mov file (or really any media file that QuickTime is capable of dealing with) and start playing it, loading its visual content into its internal Jitter matrix. But that matrix is only made visible when you send it a bang, which causes it to send out a jit_matrix message to jit.window telling it where in memory to look to get the data to be displayed.