Novel Techniques for Large-Scale and Cost-Effective Video Services

Despite the advance of network technologies in the past decade, providing video services to a large number of users remains a major technical challenge. This is especially true when it comes to serving high-definition videos. This thesis makes two contributions towards providing large-scale and cost-effective video services. 1) We consider the problem of periodic broadcast of popular videos in client/server video systems and present two novel techniques. Our research advances the state of the art with a segmentation rule that can generate a series of broadcast designs, among which we can choose the one that results in the smallest broadcast latency. We show that this rule allows us to design the broadcast technique that is the fastest up to date. 2) We then look at the problem of service scheduling in fully distributed peer-to-peer video systems, where a large number of hosts collaborate for the purpose of video sharing. Our proposed technique allows a client to be served by a server that is beyond its own file look up scope and can dynamically adjust client and server matches as new video requests arrive in the system. Our performance evaluation shows that these features dramatically improve the system performance to a large extent in terms of reducing service latency under a range of simulation settings

A Video Broadcasting System

Recent years have seen intensive investigations of Periodic Broadcast, an attractive paradigm for broadcasting popular videos. In this paradigm, the server simply broadcasts segments of a popular video periodically on a number of communication channels. A large number of clients can be served simultaneously by tuning into these channels to receive segments of the requested video. A playback can begin as soon as a client can access the first segment. Periodic Broadcast guarantees a small maximum service delay regardless of the number of concurrent clients. Existing periodic broadcast techniques are typically evaluated through analyses. While these results are good performance indicators, they cannot demonstrate subtle implementation difficulty that can prohibit these techniques from practical deployment. In this paper, we present the design and implementation of a video broadcasting system based on our periodic broadcast scheme called Striping Broadcast. Our experience with the system confirms that the system offers a low service delay close to its analytical guaranteed delay while requiring small storage space and low download bandwidth at a client

Exploiting Client Bandwidth for More Efficient Video Broadcast

Several periodic broadcasting schemes have been shown to be very effective in addressing the bandwidth limitation in multimedia servers. Since this approach allows many users to share a server stream, its bandwidth requirement is independent of the number of users the system is designed to support. Existing broadcasting schemes use two or less download channels at the client end to receive data. We discuss the drawbacks of this approach, and propose a new technique which allows a video session to download data through several client channels. The number of channels which can be used simultaneously is limited only by the communication capability of the client system. We prove the correctness of this client-centric approach, and provide analytical evaluations to show that it has significantly better performance than Skyscraper Broadcasting technique which has been shown to offer the best performance to date

Exploiting client bandwidth for more efficient video broadcast

Several periodic broadcasting schemes have been shown to be very effective in addressing the bandwidth limitation in multimedia servers. Since this approach allows many users to share a server stream, its bandwidth requirement is independent of the number of users the system is designed to support. Existing broadcasting schemes use two or less download channels at the client end to receive data. We discuss the drawbacks of this approach, and propose a new technique which allows a video session to download data through several client channels. The number of channels which can be used simultaneously is limited only by the communication capability of the client system. We prove the correctness of this client-centric approach, and provide analytical evaluations to show that it has significantly better performance than skyscraper broadcasting technique which has been shown to offer the best performance to date