IPTV means interactive network television. It is a brand-new technology that uses broadband cable television networks to integrate multiple technologies such as the Internet, multimedia, and communications to provide home users with multiple interactive services, including digital television. Users can enjoy IPTV services at home. IPTV is not only different from traditional analog cable TV, but also different from classic digital TV, because both traditional analog TV and classic digital TV have the characteristics of frequency division system, timing, and one-way broadcasting. Although the classic digital TV has many technological innovations compared to the analog TV, it is only a change in the signal form, and does not touch on the way of dissemination of media content.

principle
IPTV is a technology that uses broadband networks and integrates technologies such as the Internet, multimedia, and communications to provide home users with a variety of interactive services, including digital TV. Its system structure mainly includes sub-systems such as streaming media service, program acquisition and editing, storage, and authentication and billing. The main storage and transmission content is streaming media files with the MPEG-2/4 standard as the encoding core, which is based on IP network transmission. Set up content distribution service nodes, configure streaming media services and storage devices, and the user terminal can be an IP set-top box + TV, or a PC. IPTV can use the infrastructure of the cable television network, with home TV as the main terminal equipment, and provide multiple digital media services including TV programs through the Internet protocol.

The main features of IPTV are shown in the following 4 aspects:
(1) Being carried on the IP network, it can provide users with high-quality digital media information services;
(2) Realize the substantial interaction between media providers and media consumers, and users can interact on-demand content they like;
(3) IPTV can provide real-time and non-real-time services, IP technology and personalized on-demand services, enabling users to obtain real-time and non-real-time media programs provided by broadband IP networks on demand;
(4) Users can freely choose the video programs provided by various websites on the broadband IP network.

System Components
The IPTV system consists of three parts: front-end, network transmission and terminal equipment. The IPTV system is characterized by strong real-time, more suitable for interactive on-demand, and can also be broadcast. The transmission, distribution, return and management of information are completed by the system management part. The specific roles of each part are as follows:

1. Front-end equipment
   The IPTV front-end must have and complete two functions of program collection and storage and service. Program collection includes program reception, program compression coding or transform coding and formatting, encryption and digital rights management (DRM) packaging, and program generation. The program storage and service completes the large-scale storage or broadcasting service of the program generated after the program collection program is processed. The broadcasting service here not only needs to broadcast the encrypted video and audio streaming media program from the video server in the way of IP unicast or multicast, but also authenticate the user or user terminal device and obtain the authorization/key server from the DRM The DRM authorization/key is transmitted to the authenticated user or user terminal device, so that the user can decrypt and play the received encrypted video and audio streaming media program.
2. Network transmission
   The IPTV network system is completed by an IP backbone network, an IP metropolitan area network, a cable TV headend or a telecommunications center station, and the corresponding broadband access network. The basic task of the backbone network and the metropolitan area network is to route and exchange the video and audio streaming media program streams sent by IP unicast or multicast. According to the corresponding broadband access network, the cable TV head-end or telecom center station will stream IP video and audio streaming media programs in the way of IP over DOCSIS or IP over DSL, and pass the CMTS appraisal on the front-end of the cable TV or the digital telecom center station. Subscriber line access multiplexer (DSLAM) equipment is sent to the user.
3. Terminal reception
   IPTV user equipment is used to receive, store, play and forward IP video and audio streaming media programs. Terminal equipment includes STB, PC, player, etc. The hardware of the basic IPTV user terminal equipment does not have a built-in modem, but only has an Ethernet interface, which is connected to the outside. The integrated IPTV user terminal equipment has a variety of built-in modems, which can be directly connected to the broadband network. Electronic program guide (EPG), user management, media asset management, charging and related software for various application services are also necessary components of the IPTV system.