Video Streaming

Video on demand (VOD) is a media distribution system that allows users to access videos without a traditional video playback device and the constraints of a typical static broadcasting schedule. In the 20th century, broadcasting in the form of over-the-air programming was the most common form of media distribution. As Internet and IPTV technologies continued to develop in the 1990s, consumers began to gravitate towards non-traditional modes of content consumption, which culminated in the arrival of VOD on televisions and personal computers.

Unlike broadcast television, VOD systems initially required each user to have an Internet connection with considerable bandwidth to access each system's content. In 2000, the Fraunhofer Institute IIS developed the JPEG2000 codec, which enabled the distribution of movies via Digital Cinema Packages. This technology has since expanded its services from feature-film productions to include broadcast television programmes and has led to lower bandwidth requirements for VOD applications. Disney, Paramount, Sony, Universal and Warner Bros. subsequently launched the Digital Cinema Initiative, in 2002.

Television VOD systems can stream content, either through a traditional set-top box or through remote devices such as computers, tablets, and smartphones. VOD users can permanently download content to a device such as a computer, digital video recorder (DVR) or a portable media player for continued viewing. The majority of cable and telephone company–based television providers offer VOD streaming, whereby a user selects a video programme that begins to play immediately, or downloading to a DVR rented or purchased from the provider, or to a PC or to a portable device for deferred viewing.

Streaming media has emerged as an increasingly popular medium of VOD provision. Desktop client applications such as the Apple iTunes online content store and Smart TV apps such as Amazon Prime Video allow temporary rentals and purchases of video entertainment content. Other Internet-based VOD systems provide users with access to bundles of video entertainment content rather than individual movies and shows. The most common of these systems, Netflix, Hulu, Disney+, Peacock, HBO Max and Paramount+, use a subscription model that requires users to pay a monthly fee for access to a selection of movies, television shows, and original series. In contrast, YouTube, another Internet-based VOD system, uses an advertising-funded model in which users can access most of its video content free of cost but must pay a subscription fee for premium content. Some airlines offer VOD services as in-flight entertainment to passengers through video screens embedded in seats or externally provided portable media players.

Video on demand is becoming a growing platform to view digital content in 2022.

Functionality

Downloading and streaming VOD systems provide the user with features of portable media players and DVD players. Some VOD systems store and stream programmes from hard disk drives and use a memory buffer to allow the user to fast forward and rewind videos. It is possible to put video servers on local area networks; these can provide rapid responses to users. Cable companies have rolled out their own versions of VOD services through apps, allowing television access wherever there is a device that is Internet capable. Cable media companies have combined VOD with live streaming services. The early-2020s launches of apps from cable companies (e.g. NBC's Peacock, CBS's Paramount+) are attempts to compete with Subscription Video on Demand (SVOD) services because they lack live news and sports content. Streaming video servers can serve a wide community via a WAN but responsiveness may be reduced. Download VOD services are practical in homes equipped with cable modems or DSL connections. Servers for traditional cable and telco VOD services are usually placed at the cable head-end, serving a particular market and cable hubs in larger markets. In the telco world, they are placed in either the central office or a newly created location called a Video Head-End Office (VHO).

History

VOD services first appeared in the early 1990s. Until then, it was not thought possible that a television programme could be squeezed into the limited telecommunication bandwidth of a copper telephone cable to provide a VOD service of acceptable quality as the required bandwidth of a digital television signal is around 200Mbps, which is 2,000 times greater than the bandwidth of a speech signal over a copper telephone wire.

VOD services were only made possible as a result of two major technological developments: MPEG ( motion-compensated DCT) video compression and asymmetric digital subscriber line (ADSL) data transmission.

A VOD service was proposed as early as 1986 in Japan, where there were plans to develop an "Integrated Network System" service. It was not possible, however, to practically implement such a VOD service until the adoption of DCT and ADSL technologies in the early 1990s. The first VOD systems used tapes as the real-time source of video streams. GTE started as a trial in 1990 with AT&T providing all components. By 1992, VOD servers were supplying previously encoded digital video from disks and DRAM.

In the US, the 1982 anti-trust break-up of AT&T resulted in several smaller telephone companies nicknamed Baby Bells. Following this, the Cable Communications Policy Act of 1984 prohibited telephone companies from providing video services within their operating regions. In 1993 the National Communication and Information Infrastructure (NII) was proposed and passed by the US House and Senate, opening the way for the seven Baby Bells—Ameritech, Bell Atlantic, BellSouth, NYNEX, Pacific Telesis, Southwestern Bell, and US West—to implement VOD systems. These companies and others began holding trials to set up systems for supplying video on demand over telephone and cable lines.

In November 1992, Bell Atlantic announced a VOD trial. IBM was developing a video server code-named Tiger Shark. Concurrently, Digital Equipment Corporation (DEC) was developing a scalable video server configured from small-to-large for a range of video streams. Bell Atlantic selected IBM and in April 1993 the system became the first VOD over ADSL to be deployed outside the lab, serving 50 video streams. In June 1993, US West filed for a patent to register a proprietary system consisting of the Digital Equipment Corporation Interactive Information Server, Scientific Atlanta providing the network, and 3DO as the set-top box with video streams and other information to be deployed to 2,500 homes. In 1994–95, US West filed for a patent concerning the provision of VOD in several cities: 330,000 subscribers in Denver, 290,000 in Minneapolis, and 140,000 in Portland. In early 1994, British Telecommunications (BT) introduced a trial VOD service in the United Kingdom. It used the DCT-based MPEG-1 and MPEG-2 video compression standards, along with ADSL technology.

Many VOD trials were held with various combinations of server, network, and set-top box. Of these the primary players in the US were the telephone companies using DEC, Microsoft, Oracle, IBM, Hewlett-Packard, USA Video, nCube, SGI, and other servers. The DEC server system was the most-used in these trials.

The DEC VOD server architecture used interactive gateways to set up video streams and other information for delivery from any of a large number of VAX servers, enabling it in 1993 to support more than 100,000 streams with full videocassette recorder (VCR)-like functionality. In 1994, it upgraded to a DEC Alpha–based computer for its VOD servers, allowing it to support more than a million users. By 1994 the Oracle scalable VOD system used massively parallel processors to support from 500 to 30,000 users. The SGI system supported 4,000 users. The servers connected to networks of increasing size to eventually support video stream delivery to entire cities.

In the UK, from September 1994, a VOD service formed a major part of the Cambridge Digital Interactive Television Trial This provided video and data to 250 homes and several schools connected to the Cambridge Cable network, later part of NTL, now Virgin Media. The MPEG-1 encoded video was streamed over an ATM network from an ICL media server to set-top boxes designed by Acorn Online Media. The trial commenced at a speed of 2 Mbit/s to the home, subsequently increased to 25 Mbit/s."Cambridge Corners the Future in Networking"
''TUANZ Topics'', Volume 05, No. 10, November 1995. The content was provided by the BBC
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