The IPTV or Internet Protocol Television integrates the TV compression technology and IT data technology to stream TV and video as a consistent flow of data via the internet. The Premium IPTV server needs a set top box connected to a DSL line. The set top box is responsible for reassembling the packets into the coherent video streams and then decoding the data. When computers are involved, you don’t need any set top boxes.
There are two types of IPTV services: Multicast and unicast streaming. There are many channels multicast from, a national headend to the local offices simultaneously. But only a few channels are cast at the same time, as the DSL bandwidth is less than the cables. Rather than using this, use IGMP or IP Group Membership Protocol. In this a set top box requests a new channel. When the request is received by the local office, it is firstly checked if the user has the access permission, then it directs the routers to add particular users to the channel’s distribution list. Hence, the signals that are currently requested are then sent to the user.
The multicast technology doesn’t support the VoD or Video on Demand services as it needs a unique stream for a specific user. In order to support the VoD services, the local offices are required to generate a unicast stream that tends to target a specific user. The Unicast stream is controlled by the RTSP or Real Time Streaming Protocol that offers a DVD style control over the TV programs and let you stop, play or pause the programs while they are watching it. The entire process is delineated below:
- Acquiring the programming
The programs that the IPTV Company delivers to you are owned by some entity. To disperse the content, the IPTV should gain the rights to solicit and disperse this material. A Headend collects the media streams by decoding or recoding and then multicast it for distribution. The headend can be classified into three sections: reception, encoding and encryption, and distribution.
The received output is then injected into an encoding device to offer to the users. These streams are then encoded in MPEG2 or MPEG4. The latter costs higher but the encoded data requires less bandwidth. Once the content is demodulated and multicast IP encoded, encryption is applied to the content to protect it from unauthorized access. Get more info on encoding here.
The IPTV distribution network should cover wide area, proper bandwidth and quality services to the users to deliver the IPTV content. Network also needs a small bandwidth to deliver the revenue generating programs like advertising.