Skeltrack is a Free and Open Source Software library for skeleton tracking.
It allows to extract a number of skeleton joints from depth images such as the ones given by a Kinect device.
The application shown in the video is an example that is shipped with the library.
Skeltrack was created by Igalia and is released under LGPL. It is implemented in GLib and provides an easy to use asynchronous API.
To learn more, visit: github.com/joaquimrocha/Skeltrack