Continuous recognition and tracking of objects in live video captured on a mobile device enables real-time user interaction. We demonstrate a streaming mobile augmented reality system with 1 second latency. User interest is automatically inferred from camera movements, so the user never has to press a button. Our system is used to identify and track book and CD covers in real time on a phone's viewfinder. Efficient motion estimation is performed at 30 frames per second on a phone, while fast search through a database of 20,000 images is performed on a server.