Accelerated video encoding using render context information

In this paper, we present a method to speed up video encoding of GPU rendered 3D scenes, which is particularly suited for the efficient and low-delay encoding of 3D game output as a video stream. The main idea of our approach is to calculate motion vectors directly from the 3D scene information used during rendering of the scene. This allows the omission of the computationally expensive motion estimation search algorithms found in most of today´s video encoders. The presented method intercepts the graphics commands during runtime of 3D computer games to capture the required projection information without requiring any modification of the game executable. We demonstrate that this approach is applicable to games based on Linux/OpenGL as well as Windows/DirectX. In experimental results we show an acceleration of video encoding performance of approximately 25% with almost no degradation in image quality.