Aren there simple mocap file libraries already available in the internet?
Yes there are pre-made mocap data in the internet, which is not expensive to buy. For some simple projects this is possibly the way to go. MOTIONCAPTURE3D does not provide pre-made data, but data captured for your particular movie/game/commercial project, customised according to your script. The end result is what you have imagined and planned, and not an “anthology” of other companies’ projects.