Network TV technology with time-shift playback

With the development of multimedia technology and the popularization of broadband networks, streaming media technology has become more and more widely used, although streaming live media technology is positioned to provide real-time streaming services. However, the current user needs are also diverse. How to solve the contradiction between the real-time performance of the live broadcast system and the user's personalized playback needs, the "time-shift" playback technology has been put on the agenda by streaming media technology manufacturers.

Technical overview

Live broadcast time shift In short, you can play back live content at any time in the past, which is live broadcast time shift. This technology is mainly used in emerging Internet TV stations.

Because traditional TV signals are limited by transmission and broadcast control modes, traditional TV live broadcasts can only be pushed in one direction-viewers cannot play back live broadcast content in real time. This will make the audience uncomfortable at some point-because the damn work call delayed a wonderful World Cup goal. With the development of encoding technology, streaming media technology and the improvement of network bandwidth, IPTV and emerging network television stations came into being. Everyone is most familiar with: China Internet TV.

The principle of live broadcast time-shifting technology: through the encoding and transcoding system, the ordinary TV signal is output as a stream (such as MPEG-4 format), and it is sliced ​​and indexed, and then the stream is packaged and distributed through the streaming media server, and finally synchronized Output to various terminals (TV, PC monitor, mobile phone). The live content that the end user sees can be played back at will. The advantages of live broadcast time-shifting technology: its system transmission is based on the HTTP protocol, which can span enterprise firewalls and cover more user groups. At present, Xiamen Radio and Television Network TV Station uses VIEWGOOD (Ancient) to achieve a unique and efficient way. The combination of unlimited storage and real-time streaming cache realizes seamless integration between recording and live broadcasting. Users can arbitrarily choose the channel, code rate, and time point, can watch any program at any time, and can return to the live broadcast point at any time. The dedicated Xiamen Radio and Television Network TV player improves the user's high-definition experience.

Technology Architecture

In response to this problem that is common in existing live broadcast systems, VIEWGOOD has designed a live streaming server that supports time-shifting function for Xiamen Radio and Television: Clear Live Server. The server uses an innovative time and calculation method to realize the real-time time shift function.

WebLIVE live broadcast server architecture is shown in Figure 1. Among them, the collection and encoding process is used for real-time collection and encoding of multimedia data; the data receiving process is used to receive data from the data collection and encoding process; the WebLIVE server process is used to manage the data of all channels and submit data to the playback stream process according to the request ; The playback stream process sends data to the player according to the instructions of the HTTP communication process; the HTTP communication process is used to process the HTTP request of the WebPlayer player, and the processing result is sent to the player board process in a control message. The computing power, network bandwidth, and disk I / O capabilities of the server can easily become the bottleneck of the system. Due to the small amount of HTTP communication data, the data collection and encoding process and the HTTP communication process can be run on separate servers. The remaining three The processes run on the same server, and the servers are named acquisition server, main control server and playback server according to the process name and function. Since a single main control server can manage multiple streaming servers, the system can implement centralized control of all users through flexible deployment to support multiple encoding formats and multiple clients. At the same time, the system can make full use of the bandwidth of multiple playback servers to increase the concurrent number of the entire system.

According to this deployment, during the live broadcast process, the client first obtains the live broadcast server and channel related information from the Web server, and submits the channel request to the main control server. After the main control server processes the request, it first sends the control information to the streaming server, and then The streaming server sends data to the player accordingly.

Technology Architecture

Discrete high-definition network TV technology based on seamless time-shift playback

Special Application Staples

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