There is continuous development in the transmission of television broadcasts. The most efficient transmission mode is IPTV, a collection of protocol, hardware, infrastructure and software. A series of IP packets encoded for the delivery of video streaming is broadcast in IPTV.
In general, IPTV sends only the program requested by the viewer. A new stream is transmitted to the viewer when the channel is changed. Traditional TV, however, broadcasts all the channels simultaneously.
IPTV services have three main features:
- VOD: Video on demand (VOD) is an option available to the users of IPTV. Each user is given the option to choose from a catalog of videos and watch them as many times as required. This feature uses unicast transmission, whereas normal TV broadcasts use multicast transmission. Real Time Streaming Protocol is used for VOD.
- DVR: IPTV allows users to watch TV shows broadcast in the past using digital video recorder (DVR), which is also known as time shifted programming. Providers of IPTV allow users to watch recorded shows without DVR devices. There is a live DVR system at the provider’s end, making DVR more cost effective and efficient. Users can watch replays or start a TV program over from an interactive menu.
- Live Television: IPTV allows users to watch live transmissions with minimal latency. It provides live television broadcasts either with or without interactivity, without being just like traditional TV broadcasts. The protocol used for live television is Internet Group Management Protocol (IGMP) version 2.
The biggest limitation is that IPTV broadcasts requires a certain amount of consistent bandwidth for data to be streamed in order to deliver right number of moving pictures frames. So for providers with high IPTV customer base, customer could experience packets loss and delays in transmission.