Submitted to the Department of Electrical Engineering and Computer Science in Partial Fulfillment of the Requirements for the Degree of Master of Science in Electrical Engineering

Wavelet-based techniques are becoming increasingly widely used for encoding image and video signals. Wavelet-coded video streams are highly compressible and have considerable amount of error resilience built-in. These two features are critical to the performance of a real-time video coding system that communicates over a lossy transmission medium. A wavelet-based adaptive coding scheme is proposed in this thesis. It is specifically engineered to transport real-time video over packet-switching networks that provide services on a best-effort basis. The goal is to maximize the perceptual quality of the delivered video and to accommodate other flow controlled traffic such as TCP. The proposed adaptive scheme utilizes two key mechanisms a multiresolution codec and an overload controller. The multiresolution codec is capable of encoding and decoding a video stream at different bit-rates. The particular bit-rate chosen for encoding or decoding a video frame is usually determined by external factors such as available system or network resources. The overload control unit in the sender performs end-to-end flow control based on various feedback information from the network and/or the receiver. It then estimates the output rate of the encoder. Provided that the encoder strictly follows this estimate, network congestion and packet loss rate will be minimized. In turn, this provides opportunities for better error concealment at the receiver. Thesis Supervisor: John T. Wroclawski Title: Research Scientist