16-10-2010, 02:29 PM
Interactive television
Interactive television (generally known as ITV or sometimes as iTV when used as branding) describes a number of techniques that allow viewers to interact with television content as they view it.
Definitions of interactive television
Interactive television represents a continuum from low interactivity (TV on/off, volume, changing channels) to moderate interactivity (simple movies on demand without player controls) and high interactivity in which, for example, an audience member affects the program being watched. The most obvious example of this would be any kind of real-time voting on the screen, in which audience votes create decisions that are reflected in how the show continues. A return path to the program provider is not necessary to have an interactive program experience. Once a movie is downloaded for example, controls may all be local. The page link was needed to download the program, but texts and software which can be executed locally at the set-top box or IRD (Integrated Receiver Decoder) may occur automatically, once the viewer enters the channel.
[edit] Return path
To be truly interactive, the viewer must be able to alter the viewing experience (e.g. choose which angle to watch a football match), or return information to the broadcaster.
This "return path" or "back channel" can be by telephone, mobile SMS (text messages), radio, digital subscriber lines (ADSL) or cable.
Cable TV viewers receive their programs via a cable, and in the integrated cable return path enabled platforms, they use the same cable as a return path.
Satellite viewers (mostly) return information to the broadcaster via their regular telephone lines. They are charged for this service on their regular telephone bill. An Internet connection via ADSL, or other, data communications technology, is also being increasingly used.
Interactive TV can also be delivered via a terrestrial aerial (Digital Terrestrial TV such as 'Freeview' in the UK). In this case, there is often no 'return path' as such - so data cannot be sent back to the broadcaster (so you could not, for instance, vote on a TV show, or order a product sample) . However, interactivity is still possible as there is still the opportunity to interact with an application which is broadcast and downloaded to the set-top box (so you could still choose camera angles, play games etc).
Increasingly the return path is becoming a broadband IP connection, and some hybrid receivers are now capable of displaying video from either the IP connection or from traditional tuners. Some devices are now dedicated to displaying video only from the IP channel, which has given rise to IPTV - Internet Protocol Television. The rise of the "broadband return path" has given new relevance to Interactive TV, as it opens up the need to interact with Video on Demand servers, advertisers, and web site operators.
for more ::>
http://en.wikipediawiki/E-commerce
