Abstract: Adaptive system and method for interacting with and navigating 2D and 3D audiovisual content by interpreting the side to side and/or up and down physical gestures and sounds of a multi-person audience. The system may be used in a movie theatre, stadium, music arena, or other venue where an audience views the same view screen. A camera pointed at the audience captures audience motion and a microphone captures sounds. Optical flow is determined by comparing successive video frames. A Motion Index between ?100 and 100 is calculated using Optical flow, comparing more recent Optical Flow vectors with previous values. Methods are provided to give equal weight to audience members closer to and further from the camera. Motion Index Values are used to control and interact with content scenarios.