Steven W. Carter

Efficient broadcasting protocols for video on demand

Broadcasting protocols can improve the efficiency of video on demand services by reducing the bandwidth required to transmit videos that are simultaneously watched by many viewers. We present two broadcasting protocols that achieve nearly the same low bandwidth as the best extant broadcasting protocol while guaranteeing a lower maximum access time. Our first protocol, cautious harmonic broadcasting, requires somewhat more bandwidth than our second protocol, quasi-harmonic broadcasting, but is also much simpler to implement.

A low bandwidth broadcasting protocol for video on demand

Broadcasting protocols can improve the efficiency of video on demand services by reducing the bandwidth required to transmit videos that are simultaneously watched by many viewers. We present a polyharmonic broadcasting protocol that requires less bandwidth than the best extant protocols to achieve the same low maximum waiting time. We also show how to modify the protocol to accommodate very long videos without increasing the buffering capacity of the set-top box.

Hybrid broadcasting protocol for video on demand

Broadcasting protocols can improve the efficiency of video on demand services by reducing the bandwidth required to transmit videos that are simultaneously watched by many viewers. It has been recently shown that broadcasting protocols using a very large number of very low bandwidth streams for each video required less total bandwidth than protocols using a few high-bandwidth streams shared by all videos. We present a hybrid broadcasting protocol that combines the advantages of these two classes of protocols. Our pagoda broadcasting protocol uses only a small number of high-bandwidth streams and requires only slightly more bandwidth than the best extant protocols to achieve a given maximum waiting time.

Improving bandwidth efficiency of video-on-demand servers

Abstract Video-on-demand (VOD) servers have a limited amount of bandwidth with which to service client requests. Conventional VOD servers dedicate a unique stream of data for each client, and that strategy can quickly allocate all of the available bandwidth on the server. We describe a system called stream tapping that allows clients to “tap” into existing streams on the VOD server. By using existing streams as much as possible, clients can reduce the amount of new bandwidth they require, and that allows more clients to use the server at once, reducing client latency. Stream tapping uses less than 20% of the bandwidth required by a conventional VOD server for popular videos, and it performs better than many other strategies designed to improve VOD servers.

Video-on-demand broadcasting protocols

Video-on-demand (VOD) will one day allow clients to watch the video of their choice at the time of their choice. It will be less complicated to use than a typical web browser, and it will only require that the clients have a set-top box (STB) connected to their television set. The STB will allow the clients to navigate a VOD servers video library, and then it will handle the reception and display of the video once the clients make a selection. It is possible that the VOD service will even be interactive, allowing clients to use VCR controls such as pause, rewind, and fast forward while viewing their requests. In this case the STB will also be responsible for communicating the desired interactions to the VOD server.

A universal distribution protocol for video-on-demand

Most existing distribution protocols for video-on-demand are tailored for a specific range of request arrival rates and do not perform well beyond that range. We present a universal distribution protocol based on L. Juhn and L. Tsengs (1998) fast broadcasting protocol. Our protocol performs as well as the best reactive protocol at low-to-moderate request arrival rates and reverts to the fast broadcasting protocol at high arrival rates.

Reactive broadcasting protocol for video on demand

We propose a reactive broadcasting protocol that addresses the problem of distributing moderately popular videos in a more efficient fashion. Like all efficient broadcasting protocols, reactive broadcasting assumes that the customer set-top box has enough local storage to store at least one half of each video being watched. Unlike other broadcasting protocols, reactive broadcasting only broadcasts the later portions of each video. the initial segment of each video is distributed on demand using a stream tapping protocol. Our simulations show that reactive broadcasting outperforms both conventional broadcasting protocols and pure stream tapping for a wide range of video request rates.

Combining pay-per-view and video-on-demand services

Most efforts aimed at reducing the costs of video-on-demand services have focussed on reducing the cost of distributing the top ten to twenty videos by broadcasting them in a periodic fashion rather than waiting for individual requests. Unfortunately nearly all existing VoD broadcasting protocols require client set-top boxes (STB) to include enough local storage to store up to 55 percent of each video being viewed. Here we present a novel VoD broadcasting protocol that does not make that demand. Our dual broadcasting protocol can accommodate clients who do not have any storage device in their STB while providing a much lower maximum waiting time to customers whose STB includes a disk drive. We also discuss two possible extensions to this new protocol. One of them is aimed at reducing the bandwidth requirements of the protocol while the other extends the functionality of the VoD service by providing reverse and fast forward controls.