Interactive Video Delivery Services

Interactive Video Delivery ServicesVideo-On-DemandInteractive ServicesInteractive video tar operate argon a of import change in the TV interfaceparadigm. They shift the delivery paradigm from carrying many simultaneous parallelstreams (channels) to one that carries co-occurrent overturees through separate channels into adatabase. Traditionally, in a broadcast TV governing body, many stations broadcast their programssimultaneously and the exploiter selects a particular channel to view. As a result, a user isrestricted to a chronology of parallel and competing programming whereas, an interactive governance makes all programming in stock(predicate) to its users without this restriction. at that place is notemporal restriction. All programming becomes available any time to the user.Types of Interactive ServicesBased on the amount of interactivity allowed (adapted from 4), interactive services notify be classified into several categories.The user is a passive participant and ha s no control over the session in broadcast (No-VOD) services that are similar to broadcast TV.The user signs up and pays for specific programming, similar to existing CATV PPV services in pay-per-view (PPV) services.The users are grouped based on a doorsill of interest in quasi video-on-demand (Q-VOD) services. By switching to a various group, users can perform rudimentary temporal control activities.The functions like prior and pilfer are simulated by transitions in discrete time intervals (on the order of 5 minutes) in near video-on-demand (N-VOD) services. The multiple channels with the same programming skew in time 5, 15 can provide this capability.The user has complete control over the session presentation in true video-on-demand (T-VOD) services. The user has full-function VCR (virtual VCR) capabilities including forward and reverse play, freeze, and random positioning. For T-VOD, only a single channel is necessary multiple channels become redundant.Technological Inhibito rsThere are other inhibiting issues to the omnipresent deployment of interactive multimedia applications than just technological issues. In the digital environment, breeding is readily copied, reproduced, and altered, jeopardizing the established markets of the information providers. To convince an information provider to accept an all-digital system, sure incentives like mechanisms like encryption to protect intellectual property rights that will maintain their data and thus help them stay in business are needed. (The Internet does not copy data, people copy data.)System Components for Video-on-Demand5A detailed analysis of these issues is beyond the scope of this paper. An interesting survey of theintellectual property rights task has been provided by Samuelson 14.Hundreds (if not thousands) of users with different viewing preferences will access a VOD system simultaneously. The quality of each session must remain within stipulate bounds to achieve customer satisfaction. This ensures the quality of the system. We will survey the individual technologies in the context of an end-to-end architecture for a VOD system.A typical VOD scenario contains a local database and horde connected to user homesvia a communications network. The user home consists of a network interface coupled to adisplay 4. The user interacts with the system via a mouse or a computer keyboard.Fig. 2 illustrates this architecture.user interfaceand displayhigh-speedbackbonelocal databaselocalserverhomeviewernetwork interfacemultimedia archive and distributormultimedia archiveFigure 2 A Simple VOD Architecture prudence of System Resources in VODWe identified some of the technical lines in designing a VOD system in the previous sections. A VOD system is required to patronise a large customer population and many movie titles. Most existing prototypes are constricted to laboratory or office environments and support at most a few hundred users and up to a hundred movies. Large scale commerc ial systemsshould need to more closely match the per-user choice requirements and usage patterns toachieve economic feasibility. In this section, we look over some of these problems and discussexisting research in this area.Resource ReservationOne of the fundamental problems in developing a VOD system is one of storage and network I/Obandwidth management. The VOD system possesses a finite amount of resources measured interms of storage I/O and communication bandwidths. As various customers compete for the samesystem resources, efficient schemes that ensure fairness of allocation drop to be designed.The service provider wants to generate the maximum revenue from the offered services. Abalance between these two often opposing requirements is necessary to tap the effectivenessbenefits of the system. The first step to solve this problem is the development of anaccurate system model. We use the model proposed in Fig 2 as the basis for the disputeof this discussion.The end-to-end VOD system comprises of three basic components the storage server,the network, and the user interface. The metadata server provides an additional level ofcomplexity to the system model. The time dependency of continuous media requires theVOD system to ensure that the data transmission mechanism can provide for strict deadlines.If these deadlines are missed, it is possible for the quality of the session to degrade. To ensure customer satisfaction, resources should be reserved along the entire data path of a connection on a per-session basis. The complexity of the resource reservation mechanism depends on theapplication down the stairs consideration. Interactive services need the resource reservation to be made per-session along the entire data path, including at the source.A crucial factor which is affect resource reservation is Quality-of-Service (QOS). The common interpretation of QOS is from a network perspective rather than a user or customer perspective. A more fitted view makes use of the two perspectives and yields twoQOS characterizations (we can call them delivery quality and system QOS). A presentchallenge is to identify the mapping from delivery quality to system QOS for a range ofsystem design parameters (e.g., data compression and network switching modes).User Traffic CharacterizationAlthough customers access the VOD system randomly, having a priori knowledge aboutuser access patterns can lead to a more efficient design. The system can make use of this information to manage network and storage bandwidths. As an example, if the traffic characteristics indicate that a movie is popular at a particular site, the system can reprise the movie locally to increase availability.The access pattern of users to the system will not be uniform over a given24 hr period. Typically, one would expect the load to be low to moderate during thedaytime and to increase gradually through the eventide and decrease again during the night.A suppositious graph characteri zing the access to a VOD database for a 24 hour periodis shown in Fig. 4. The access to the database is high during the evening hours, peaks ataround 900 PM, and is low-to-moderate during the day. This access pattern can be used fordesigning schemes for various considerations like resource management to update popularity tables, redistribute data, and reconfigure the system during off-peak hours.05 10 15 20time-of-daydatabase-loadFigure 4 A Schematic Daily-Access Model for a VOD SystemSimilar models can be implemented and maintained for different geographical regions, moviecategories, and individual titles. Such models are able to accommodate the differences in programming choices (e.g., childrens movies are more popular during the early evening hours) of different user groups. However, the complexity of these models, and their tractability is still to be established.Load BalancingAn issue related directly to resource reservation is load balancing. The load balancing of VOD can be v iewed as a combination of two sub-problems (i) The movie-storageallocation problem and (ii) the resource location and connection establishment mechanism.Even though these problems are solved more easily individually, they are not independentwith respect to performance. From the perspective of a generic interactivesystem, solving these issues is an open problem however, simplifications can yield tractable solutions.As an example, if one assumes that a VOD system supports only stored data i.e., movieshave to be digitized and stored before they can become available online, then the datacharacteristics of a movie are well known in advance (e.g., the system has a priori knowledgeabout the average bandwidth, die rates, burst durations, etc.). This knowledge once available, can be used to simplify the design process. Making use of the metadata mechanism as described in class 3 simplifies the task of management by decoupling the storage problem from the location problem.