What I wanted was dancing material with an unchanging background and a static camera. Now there is YouTube so it is really easy to find this. Next I downloaded the FLV movie using a 3rd party tool (there are many). I used "FLV Extract" to get the video stream from the FLV file as an AVI file. Then I used Virtualdub to crop it to a short segment. Converted that segment into a GIF animation with GIF Movie Gear, then finally imported the animation to a Flash timeline.
Next I attempted to track the left wrist of the dancer to see how much work it is. As a first test it took about 5 minutes of concentrated effort to mark 50 frames. Mostly I was so slow because I needed to move forward and create keyframes in the timeline and drag the joint marker with my mouse. I think if I made a small tool that let me just tap on a joint with my drawing pad, I could manage in under 5 seconds per joint per frame.
At least 20 joints would be necessary to make a stick figure dance like the dancer. Three minutes of YouTube video at 12 fps is 2160 frames times 20 joints is 43200 taps times 5 seconds is 60 hours! And of course this data is 2D, so it isn't even clear what could be accomplished with it. One thing did occur to me though -> you could use this as an affordable motion capture solution for games. Suppose you have a front camera and a side camera filming the same footage, so 120 hours of work to track it. Send the task to China, suppose it costs $5/hour -> total $600 for probably all of the motions needed for a small game.
