 <p>The site <a href="http://research.microsoft.com/en-us/um/people/zliu/ActionRecoRsrc/" rel="nofollow">http://research.microsoft.com/en-us/um/people/zliu/ActionRecoRsrc/</a> tells you exactly how they're organised. They also provide some C++ example loaders.</p> <p>"The format of the skeleton file is as follows. The first integer is the number of frames. The second integer is the number of joints which is always 20. For each frame, the first integer is the number of rows. This integer is 40 when there is exactly one skeleton being detected in this frame. It is zero when no skeleton is detected. It is 80 when two skeletons are detected (in that case which is rare, we simply use the first skeleton in our experiments). For most of the frames, the number of rows is 40. Each joint corresponds to two rows. The first row is its real world coordinates (x,y,z) and the second row is its screen coordinates plus depth (u, v, depth) where u and v are normalized to be within [0,1]. For each row, the integer at the end is supposed to be the confidence value, but it is not useful."</p> <p>Hope this helps.</p>