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Quartz Composer Video Matrix

posted by ian grant on August 10, 2006 at 10:54 pm | in moving image, quartz composer |

Here’s a screenshot of a demo patch that tiles an image (still or video) onto a user selected number of tiles. The rows/columns tiles can be fixed or animated. Three test patches are available for download.

Download link: quartz composer video matrix test files 001 - 003

Notes: These are patches in development and (except patch 001) need some tidying - the published parameters are slightly out of order on 002 and 003, but you should get the principle from patch 001.

I have been wanting a patch that does this for a while and these are really just a proof of concept and may not be the most elegant solution. There are some limitations.

Limitations
The number of X tiles (columns) can be determined interactively. Unfortunately at the moment, the number of Y tiles is fixed. If you wish to add a row you must edit the contents of the “3D Transformation” patch and add new copies of the highlighted patches (indicated below), edit that names of published keys, plumb them in (following the pattern of the others - at this and the parent level) and set the Y position of the new row. Pain. But okay if you know what size of matrix you need.

For convenience, there is an image source that switches between camera input, images and a couple of movies - you will need to remove my movies and add your own.

Development - motion detection / computer vision
I have an idea (maybe wrong) that a static matrix like this could be used as the starting point for a motion detection / camera vision thing. Imagine if you processed the video (desaturate, detect outlines for example or use the “flood fill” that appeared on the quartzcomposer-dev list recently) and had something like a kernel that could sample each cell in the matrix and output a value or a boolean dependent on the white / black balance. I don’t think the core image kernel in quartz composer can output anything other than an image - but a kernel possibly can when used in core image in a cocoa application. Interesting.

Download link: quartz composer video matrix test files 001 - 003