A Proxy Caching System for MPEG-4 Video Streaming with a Quality Adaptation Mechanism

摘要

In this paper, we propose, design, implement, and evaluate a proxy caching system for MPEG-4 video streaming services for heterogeneous users. In our system, a video stream is divided into blocks for efficient use of the cache buffer and the bandwidth. A proxy retrieves a block from a server, deposits it in its local cache buffer, and provides a requesting client with the block in time. It maintains the cache with limited capacity by replacing unnecessary cached blocks with a newly retrieved one. It also prefetches video blocks that are expected to be required in the near future. In addition, the proxy server adjusts the quality of block appropriately, because clients are heterogeneous, in terms of the available bandwidth, end-system performance, and so on. Through evaluations, we proved that our proxy caching system could provide users with a continuous and high-quality video streaming service in a heterogeneous environment.