MAX Jitter and life among cables.

Finally I managed to learn and build the patch I needed for my project, all at the same time. The idea was to feed MAX with 5 video cameras and create 5 separate videos from it. The videos created where some kind of edition of the video income, as not everything that came from each camera had to be in each final video.

So what I did was getting Ableton Live (from where I also sent two separate channels of audio) to send MIDI notes telling MAX which camera had to capture and when. I finally had to use two computers because I wanted maximum quality, therefore fireware and not USB. I could only get one fireware camera into each computer at a time (I finally got two cameras in one of the computers where I installed Windows 7 in BootCamp) because of a Quicktime limitation. So Live was telling both MAX in both computers (through a MIDI cable) exactly when to capture what.

The patch is made of one jit.qt.grab object for each camera. According to the MIDI in note, the grab objects (in a subpatcher) create little videos.

The name of the videos is set by a little subpatcher which adds up a number each time it receives

the MIDI note.

So after all the little videos have been captured by each grab object (three on one computer, two on the other one), I use jit.qt.movie to put all these videos together and export a mp4 video file that can be read by five multimedia players that I bought (the simplest way I found to play five independent videos). Again, it's a MIDI note telling the program "ok, now make a big video out of all these little ones". I created a small video in black which I could load already at when opening the patch. This way I could set the export settings before hand.

The big problem I got was when I tried to append all the videos automatically into the qt.movie object. I know there must be a way, but I didn't have the time to find it! So what I did finally was writing the name of all the videos (which is always the same). The resulting patch is rather beautiful.

I had to use sprintf because I couldn't get a message to output file locations with the $1 system. So I spent quite a lot of time finding this out, until my savior Yoann Trellu told me about sprintf.

Conclusion: I love MAX and the way it works. It takes a lot of time to learn its mechanics, but I will continue exploring its possibilities. Next I want to dive into the world of MSP which I didn't have the time to even touch! The sound was captured directly with he write_audio message of the grab object.

If anyone is interested in knowing more about the patch I just tried to explain or about the project it was used for, please don't hesitate asking me. I will answer with pleasure to all questions and suggestions.

See you all!

Pablo