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An Overview of IPTV Technology
What is IPTV?
The letters IPTV stand for internet protocol television, which is a means of transporting data information and Audio and Video (AV), across an IP based digital network. This could include Ethernet,WAN,internet or LAN. By adding set top boxes (STB), AV sources have the ability to be streamed across existing networks to TVs or PCs. IPTV can be one to one (Unicast) or one to many (Multicast).
The most effective type of transmission is offered by Multicast streams as the bandwidth can be shared amongst all of the users who want to view that particular stream. No matter how many viewers (providing the network is configured correctly), a 4Mbs stream for example, will only use that amount of bandwidth. No bandwidth is consumed if the channel is not being viewed.
Unicast transmissions are generally used for two-way transmissions - for example Video On Demand (VOD), only the person who has ordered the content can receive it. Some control can also take place such as pause, play, rewind, fast forward etc. Unicast can also be used for linking buildings via a WAN for cameras, TV channels etc. The downside of unicast on the system is bandwidth, as each viewer uses their own amount. 100 users all viewing 4Mbs of VOD will use 400Mbs of the network's bandwidth.
IPTV - The Advantages
There are numerous advantages over RF coaxial based transmissions. AV streams can simply be inserted into an existing network and viewed with no addition to the existing infrastructure. Channels can be grouped and controlled to suit personal preferences. STBs can be controlled across the network or internet VOD servers. Sport, local content and films can be added for revenue stream in perhaps a hotel, or maybe offered free to a student campus. Streams can be recorded and viewed onto PCs without the need for extra cabling and TV capture cards. This is useful for businesses, news agencies, banks etc.
Digital IP based networks are practically immune to ghosting, noise, harmonics, cross modulation, reflections etc - problems that are all common in analogue systems. Some of these problems have been resolved using digital transmission across the coaxial networks, however, some of the above still cause problems.
So to summarise, the picture quality of a correctly installed IPTV system is superior to almost all other means of transmission.
John Key runs Keydigital Productions and utilises IPTV Products from TV Over LAN in his business.
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