Multi-Threaded Real-Time Video Grabber

Abstract

Communication in general incorporates technologies with increasing number of communication modes. Special applications are developed in the area of virtual reality, multimedia communications and others where combinations of audio, video, 3D data are sent between two (or more) distant users which can commonly interact with these data. A form of so exchanged information usually requires, among others, special forms of presentation. Thus stereoscopic and virtual reality visualization devices are used to present intricately structured information in multi-modal form. There are situations where the presented information is to be rendered in real-time and transmitted to the remote user in form of a video-stream. In this case, the content is presented on a local visualization device (e.g. CAVE) being simultaneously sent to a remote device. Thus a method how to obtain rendered data from graphics hardware in real-time is necessary. The problem is, how to obtain the rendered data for transmission with minimal impact on the rendering and visualization process. In this paper, we present a method how to retrieve video stream from an arbitrary running OpenGL application, capturing every frame with minimal impact on performance.