A framework for encoding and caching of video for quality adaptive progressive download.

Progressive download of multimedia objects over the Internet (e.g. www.youtube.com), where the video is downloaded and viewed during the download process, has become an increasingly popular alternative to multimedia streaming. Due to the fluctuating bandwidth and latency of the Internet, progressive download is often not fast enough, often resulting in intermittent stalling of the video. In this paper, we first propose a variation of the existing MPEG Fine Grained Scalability (FGS) profile to create a layered video representation that is suitable for progressive download in an environment characterized by varying bitrate. We also propose an efficient caching scheme that is specifically tailored for the proposed layered video representation. The proposed layered version of the Greedy-Dual-Size cache replacement policy is shown to reduce the latency observed by the client during progressive download of video in a varying bitrate environment. Experimental results demonstrate that the proposed caching scheme improves the latency of progressive video downloads as well as the server efficiency.