Coding and transmission of digital video on the internet.

摘要

Transmitting digital video over the current Internet is difficult. There is a big gap between Internet bandwidth and video bitrate. The current Internet is a best effort, unreliable network with no QoS guarantees. These difficulties require that an effective Internet video coding and transmission scheme to be low bitrate and robust.;The conflicting requirements of low bitrate and robustness requires a delicate balance between them. Traditional coding methods are optimized for compression ratio and rely on transmission schemes to provide robustness. The current Internet environment cannot provide desired robustness without sacrificing low delay and other real time requirements. Traditional schemes dealing with packet loss and error recovery are not suitable for the Internet because they are designed for specific environments under specific assumptions.;In this thesis we propose a practical approach to the problem by conducting a comprehensive Internet traffic behavior study and we use the results as guidelines for the design and implementations of a low bitrate and robust video coding and transmission scheme. This thesis tackles problems in both coding and transmission. For coding, a hybrid coding scheme is proposed to increase the robustness. For transmission, an effective dependency isolation algorithm is designed to minimize packet loss damage. We demonstrate that by understanding the Internet video traffic loss behavior and properly balancing the bitrate and robustness through improved I frame coding and efficient frame packetization, a low bitrate and robust Internet video coding and transmission scheme can be realized.