Zitiere Hans-Christoph Steiner hans@eds.org:
Gem has [pix_movement]. PDP has some movement and color tracking objects also.
[pix_movement] puts the difference between two adjacent rgba-frames into the alpha-channel of the 2nd. (i think it stores the difference into the grey-channel for Grey-images (which is "the" channel) and into the Y-channel for YUV-images).
to get control-data out of this, there is the [pix_blob]-object, which does blob-analysis (position and size of the blob, either in a single channel or in an overall of all channels). this way, you can do color-tracking too, although i admit it is a bit complicated. normally i'd do this with a combination of [pix_rgb2hsv] (to transform into a format with more meaningful in terms of color channels), [pix_curve]/[pix_bitmask] (to mask unwanted values) and [pix_blob]. i think it might be a bit easier in yuv-space (but i am no specialist in there)
however, the PoDoP-part of pdp is surely more sophisticated.
mfg.a.dr IOhannes