P2PTV

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The term P2PTV refers to peer-to-peer software applications designed to redistribute video streams on a p2p network, typically TV stations across the world. The draw to these applications is significant because they have the potential to make every TV channel in the world global.

The benefit of using peer-to-peer technology is similar to that of standard peer-to-peer software. Each user, while downloading, is also uploading, thus contributing to the overall available bandwidth. The video quality of the channels typically depend on how many users are watching; the video quality is better if there are more users.

Many P2PTV applications make use of the BitTorrent technology.

The potential of the technology is however limited by multiple factors, rendering the technology almost unusable for professional usage^{[verification needed]}:

No QoS. Compared to unicasting (server-client architecture used in streaming media) no one can guarantee a reliable stream, since every user is a rebroadcaster. Each viewer is a part of a chain of viewers which all can have negative influence on the reliability of the stream (by having a slow PC, a filled downlink or uplink or a unreliable consumer grade DSL or cable connection.
Over 40% extra data overhead compared to unicasting. To bypass the QoS issue, P2P networks have multiple peers send multiple traffic to other peers, introducing extra data overhead for retransmits, communication and redundancy. Dutch ISP's have calculated the traffic needed to send a P2PTV stream to a number of users, and measured 40% additional traffic usage compared to unicasting an RTSP stream to a similar audience^{[citation needed]}. Multicasting (although not a widespread internet technology) is even more efficient than unicasting, since one stream can feed a virtually unlimited number of viewers.
No control. Broadcasters prefer to be able to limit access to their content based on regions, and would like good data on viewer behaviour, such as volume, trends and viewing time. Compared to server based technologies P2PTV offers no control and no viewer feedback at all.

P2PTV may seem a more affordable solution for broadcasters, but actually the costs are moved from the broadcasters to the distributers, and from a macro view costs are increased instead of decreased. In the long term this is not of interest of the end user, since increased network costs will be charged to end users.

For professional broadcasters and distributers, a hybrid solution is used for many years. Distribution servers are not centrally installed, but are rolled out in a smart, decentralized way. A central management facility manages content distribution over multiple peer server (also known als Edge server or Cache) redistributes, strategically located near user swarms (generally popular access ISP networks), manages load balancing, redirection of users, view reporting and QoS. Examples are Akamai and VDO-X. Akamai still has to buy high cost transit traffic, but the VDO-X model introduces on-network distribution per ISP and no actual Internet distribution, introducing extreme lower distribution costs, distribution rights management and the highest QoS possible.

Although some projects target broadcasters (see below), most P2PTV technology is used to redistribute TV channels on the Internet without a proper licence to do so.

The majority of applications available broadcast mainly asian TV stations, with the exception of TVUPlayer, which carries a number of North American stations such as ESPN, ABC, Fox and CBS.