source filmmaker (medium)
Source Filmmaker (often abbreviated as SFM) is a video capture and editing application developed by Valve Software for use within the Source game engine.
Source Filmmaker was initially used as an internal tool for the development of animated shorts. Some of the earliest examples are the release trailer for Day of Defeat and the Meet the Heavy short for Team Fortress 2.
Source Filmmaker has been in open beta as of July 11, 2012, and is available for free through Steam, where uses can import custom models and maps compatible with the Source engine and use them in their own animations.