US Patent 8477174 Automatic video switching for multimedia conferencing

After a video conference is established, a video conferencing system receives a video stream from the participants of the video conference. One of the received video streams is transmitted to the conference participants (e.g. the video stream of the person currently speaking). The video conferencing system monitors a second one (or typically all) of the received video streams to determine if a designated video event (e.g. someone raising his hand) has occurred. If the designated video event has occurred, the video conferencing system switches or supplements the currently transmitted video stream to or with the second one of the received video streams that contains the designated video event. The second video stream is then transmitted to participants in the video conference. The switching of the video stream and the switching of the audio stream may be independent.