The split and merge (SAM) protocol for interactive video-on-demand systems

A true video-on-demand (VOD) system provides the ultimate flexibility in video services by allowing users to select any video programs, at any time, and to perform any VCR-like user interactions. To allow true VOD, one approach is to have a dedicated video stream for each customer. This is expensive, especially when multiple identical video streams are sent to multiple customers accessing the same video. To be commercially viable, VOD service must be priced competitively with existing video rental services. Batching may be used to reduce this cost. It allows multiple users accessing the same video to share the same video stream. The batching approach, however, complicates the provision of user interactions. Existing batching schemes only allow near VOD services. This paper describes a new protocol, called split and merge (SAM), which offers true VOD services while allowing multiple users to share the same video stream. This sharing is transparent to the users and it appears as if each has a dedicated video stream. Our approach is to split an interactive user from the batch and to serve him with a dedicated video stream. We develop an innovative way to merge these individuals back to the batching streams when they resume normal play mode. The SAM protocol therefore significantly improves the system resource utilization and the number of simultaneous users, and more importantly, allows true VOD services.published_or_final_versio

QuIVeR: A class of interactive video retrieval protocols

Video-on-demand (VOD) servers need to be efficiently designed in order to support a large number of users viewing the same or different videos at different rates. In this paper, we propose the Quasi-static Interactive Video Retrieval (QuIVeR) Protocol for this purpose when disk-array based video servers are used. Five variations - QuIVeR-1, QuIVeR-2, QuIVeR-3, QuIVeR-4 and QuIVeR-5 - are presented. The properties as well as the relative merits and demerits of each protocol are discussed. The protocols require no buffer at the server and hence, all retrieved segments are immediately transmitted to the appropriate users. The amount of buffer required at each user's set-top box is reduced to two video segments. Guarantees are provided for the avoidance of video starvation as well as buffer overflow at each user's set-top box. Numerical results, obtained using data from an MPEG coded `Star Wars' video, are provided.published_or_final_versio

DIVeR: a dynamic interactive video retrieval protocol for disk array based servers

Video-on-demand (VOD) is a very promising multimedia application of the near future. In order for such a service to be commercially viable, efficient storage and retrieval schemes need to be designed. A scheme for grouping MPEG frames into segments wherein no frames are discarded during fast playback is proposed. In addition, the Dynamic Interactive Video Retrieval (DIVeR) protocol is introduced for scheduling the retrieval of multiple users from disk-array servers.published_or_final_versio

Performance model of interactive video-on-demand systems

An interactive video-on-demand (VoD) system allows users to access video services, such as movies, electronic encyclopedia, interactive games, and educational videos from video servers on a broadband network. This paper develops a performance evaluation tool for the system design. In particular, a user activity model is developed to describe the usage of system resources, i.e., network bandwidth and video server usage, by a user as it interacts with the service. In addition, we allow batching of user requests, and the effect of such batching is captured in a batching model. Our proposed queueing model integrates both the user activity and the batching model. This model can be used to determine the requirements of network bandwidth and video server and, hence, the trade-off in communication and storage costs for different system resource configurations.published_or_final_versio

Projetos de redes para suporte de aplicações de video distribuido

Orientador: Nelson Luis Saldanha da FonsecaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: As aplicações de vídeo apresentam grande potencial de sucesso comercial na futura Rede Digital de Serviços Integrados de Faixa Larga (RDSI-FL). Estas aplicações serão também as maiores consumidoras de banda passante neste novo ambiente. Sendo assim, a compreensão dos requisitos para se prover serviços de vídeo é de suma importância para o projeto eficiente da rede. Esta dissertação estuda Distributed Home Theatre (DHT), um serviço de vídeo que permite que usuários geograficamente dispersos discutam um filme. Investiga-se aqui o compromisso existente entre a redução da banda passante e a replicação de repositórios de vídeo no projeto de redes para o fornecimento de serviços de DHT. São propostas funções de custo que permitem a avaliação deste compromisso utilizando-se de valores reais. Vários cenários são analisados: Redes sem compartilhamento de fluxo, Redes com compartilhamento de fluxo, Redes com servidores distribuídos e Redes com servidores distribuídos e compartilhamento de fluxo. Técnicas de replicação de cache/ servidor são investigadas e avaliadas frente a parâmetros tais como a distribuição dos usuários e o número de usuários por sessão DHT. A análise é estendida para incluir redes com serviços de Vídeo sob Demanda e Distributed Home Theatre.Abstract: Video services are both a major business driver and a bandwidth consumer for the future broadband integrated network (B-ISDN). Understanding different video services requirements is of paramount importance for network design. In this dissertation we study Distributed Home Theatre (DHT), a video service which allows distributed users to debate a film. We investigate the tradeoff between bandwidth reduction and program replication in the network design for the provision of the DHT services. We propose a framework to analize this tradeoff for real costs. We analize different network scenarios: networks without stream sharing, networks with stream sharing, networks with distributed servers and networks with distributed servers and stream sharing. Serverlcache replication techniques are investigated and evaluated under different user distribution and different number of users per DHT session. Moreover, we analyze networks with both DHT and video on demand services.MestradoMestre em Ciência da Computaçã