My MDD and TiBook are last-generation OS 9 machines, and neither of them come close to anything crunchy enough to handle h264. My MDD 1.42 with GeForce Ti 4600 video could barely handle 1fps of x264! It is just too processor intensive, and the amount of data probably choke the bus also. To dial down the detail enough for it to work, we'd lose the benefits. Better off converting it to MJPEG.h264 for quicktime 6At least decoder.
I would say that this one fits under "running on modern machines", at least a G5.