Video on demand
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Image:ResumeViewingOption 1.jpg Video on demand (VOD) systems allow users to select and watch video content over a network as part of an interactive television system. VOD systems either "stream" content, allowing viewing while the video is being downloaded, or "download" it in which the program is brought in its entirety to a set-top box before viewing starts.
All download and some streaming video on demand systems provide the user with a large subset of VCR functionality including pause, fast forward, fast rewind, slow forward, slow rewind, jump to previous/future frame etc. For streaming systems this requires more effort on the part of the server, and may also require greater network bandwidth.
It is possible to put video servers on LANs, in which case they can provide very rapid response to users. Streaming video servers can also serve a wider community via a WAN, in which case the responsiveness may be reduced. Download VOD services are practical to homes equipped with cable modems or DSL lines.
The first commercial VOD service was launched in Hong Kong around 1990. The technology was not mature, Video CDs were much cheaper, and pay TV was not common in Hong Kong. Hong Kong Telecom lost a large amount of money and the service was acquired by Pacific Century Cyberworks in 2000, who subsequently discontinued it.
VOD services are now available in all parts of the United States. Streaming VOD systems are available from cable providers (in tandem with cable modem technology) who use the large downstream bandwidth present on cable systems to deliver movies and television shows to end users, who can typically pause, fast-forward, and rewind VOD movies due to the low latency and random-access nature of cable technology. The large distribution of a single signal makes streaming VOD impractical for most satellite TV systems; however, EchoStar recently announced a plan to offer video on demand programming to PVR-owning subscribers of its DISH Network satellite TV service. After the programs are automatically recorded on a user's PVR, he or she can watch, play, pause, and seek at their convenience. VOD is also quite common in more expensive hotels. VOD systems that store and provide a user interface for content downloaded directly from the Internet are widely available.
Cable TV providers Telewest and NTL began VOD services in the United Kingdom in 2005 in attempt to snatch subscribers from the countries leading pay-tv distributer Sky Digital whose sattelite based network is unable to offer such a service. After securing a partnership to offer many BBC programmes the service has been a success, Telewest and their parent company NTL will soon be offering a range of programmes from other television networks such as ITV.
VOD services are available in many other parts of the world as well. The ANYTIME service provides VOD to cable providers in Taiwan and to TransACT Communications in Australia. TransACT also operates its own VOD services including sports and adult content.
It is possible to implement VOD using methods such as bandwidth skimming, which can deliver O(log n) scaling as the number of users increase.
Over IP Video (OIPV)
OIPV is an emerging technology that enables video on demand (VOD) to be transmitted over Internet Protocol (IP). It is not the same as VOIP, which is limited to voice communication. OIPV can stream video content over both broadband connections and 3G telephone networks, both of which use the IP address system to access the Internet. Streaming video on demand (VOD) can therefore be transmitted to mobile phones and other wireless devices. While many companies are competing to provide such services, a clear-cut and profitable business model has been slow to emerge in this area.
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Near Video on Demand
Near Video on Demand (NVOD) is a Pay-per-view consumer video technique used by multi-channel broadcasters using high-bandwidth distribution mechanisms such as satellite and Cable television. Multiple copies of a programme are broadcast at short time intervals (typically 10–20 minutes) providing convenience for viewers, who can watch the programme without needing to tune in at a scheduled point in time. This form is bandwidth intensive and is generally provided only by large operators with a great deal of redundant capacity.
Video on demand providers
- Adelphia
- Akimbo
- Cablevision
- Charter Communications
- CinemaNow
- Cogeco Cable
- Comcast
- Cox Communications
- HomeChoice
- iFluxx
- MovieBeam
- Movielink
- NTL
- Rogers Cable
- SaskTel
- Shaw Communications
- Síminn
- Time Warner Cable
- TransACT
- Videotron
- Worldcinemaonline
See also
News
- Tracy Swedlow's InteractiveTV Today, also known as [itvt], is a weekly email newsletter covering all aspects of interactive television, IPTV and video-on-demand, and offering news, features and interviews. It has also just launched a News Blog
- - Digital TV Weblog - analyzes business models for VOD providers
- ipTVnews.com (official site)
- Mobile TV news (official site)
- iptv forum (official site)
- iptv asia (official site)
- iptv eastern europe(official site)
- iptv (site)
External links
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