FEC-based Loss Recovery for Interactive Video Transmission – Experimental Study

Real-time interactive video transmission in the current Internet has mediocre quality because of high packet loss rates. Loss of packets belonging to a video frame manifests itself not only in the reduced quality of that frame but also in the propagation of that distortion to successive frames. This error propagation problem is inherent in any motion-based video codec because of the interdependence of encoded video frames. Since packet losses in the best-effort Internet environment cannot be prevented, minimizing the impact of these packet losses to the final video quality is important. In this paper, we present a new forward error correction (FEC) technique that effectively alleviates error propagation in the transmission of interactive video. The technique is based on our recently developed error recovery scheme called Recovery from Error Spread using Continuous Updates (RESCU). RESCU allows transport level recovery techniques previously known to be infeasible for interactive video transmission applications to be successfully used in such applications. The proposed FEC technique can be very useful when the feedback channel from the receiver is highly limited, or transmission delay is high. Both simulation and Internet experiments indicate that our proposed FEC technique effectively alleviates the error spread problem and is able to sustain much better video quality than H.261 or other conventional FEC schemes under various packet loss rates.