The implementation of streaming requires caching. Because the Internet performs intermittent asynchronous transmission based on packet transmission, for a real-time A / V source or stored A / V file, they will be decomposed into many packets during transmission. Since the network is dynamically changing, each packet is selected The routes may not be the same, so the time delay to reach the client will not be equal, and even the first data packet may arrive later. To this end, a buffer system is used to compensate for the effects of delay and jitter, and to ensure that the order of data packets is correct, so that media data can be continuously output without causing pauses in playback due to temporary network congestion. Usually the required capacity of the cache is not large, because the cache uses a circular linked list structure to store data: by discarding the content that has been played, the stream can reuse the free cache space to cache the content that has not been played later. Generally, the realization of streaming transmission requires a suitable transmission protocol. Because TCP requires more overhead, it is not suitable for transmitting real-time data. In the implementation scheme of streaming transmission, HTTP / TCP is generally used to transmit control information, and RTP / UDP is used to transmit real-time sound data.
The process of streaming transmission is generally this: after the user selects a certain streaming service, HTTP / TCP is used to exchange control information between the web browser and the web server, so as to retrieve the real-time data to be transmitted from the original information; then the client The Web browser on the machine starts the A / VHelper program and uses HTTP to retrieve the relevant parameters from the Web server to initialize the Helper program. These parameters may include directory information, A / V data encoding type, or server address related to A / V retrieval.
The A / VHelper program and the A / V server run real-time flow control protocol (RTSP) to exchange control information required for A / V transmission. Similar to the functions provided by CD players or VCRs, RTSP provides methods for manipulating playback, fast forward, fast reverse, pause, and record commands. The A / V server uses the RTP / UDP protocol to transmit A / V data to the A / V client program (the client program is generally considered to be equivalent to the Helper program). Once the A / V data reaches the client, the A / V client program can play Output.
It should be noted that in streaming, two different communication protocols RTP / UDP and RTSP / TCP are used to establish contact with the A / V server, in order to be able to redirect the output of the server to a different The destination address of the client where the program is located. The realization of streaming generally requires a dedicated server and player, the basic principle of which is shown in the figure.
The main control unit of the equipment is PLC and the HMI (Human Machine Interface) is 7" LCD colorful touch screen. The equipment has varieties of operating modes, and can automatically record and save working status.
The complete set of equipment is easy to operate, reliable in working, complete in protection and high in automation.
Fast Charging,Intelligent Fast Battery Charger,Agv Automatic Battery Charger,Agv Fast Charger
Xinxiang Taihang Jiaxin Electric Tech Co., Ltd , https://www.chargers.be