Study And Implement Of Wireless Video Streaming Media System Based On ARM

With today's information explosion, people's studying, working, entertaining and living are closely related with information resources.. And the processes of information creating, processing, and storing and transmitting require organic network and joint development of electronic technology and multimedia technology to enable the application of information to better meet people's needs. The traditional network models as a remote login, e-mail or FTP file transfers can no longer meet people's daily needs; and new developments of network technology and applications are badly needed.Embedded technology has developed rapidly all over the world in recent years. Relying on computer technology, it cuts or adds the system hardware according to the specific functional requirements to get rid of redundant parts and reduce cost, power consumption and size. It is quite reliable. At present, with the promotion of IT technology, the 32-bit ARM structure has been gradually standardized as an industry standard. And ARM based chips have been widely applied to all aspects of social life. The flexibility of embedded system design also determined its domination in a fairly long period of time.With the thorough understanding of embedded systems, the thesis designed wireless video transmission terminal hardware system according to the demand for video surveillance systems analysis. Given the the wireless video transmission system's requirement of low power consumption and good performance, system terminal hardware design uses Samsung's production of 16/32-bit RISC microprocessor S3C2440. The product is specifically designed for handheld devices, the core processor is based on the ARM 920T, with MMU, Harvard Cache architecture, and a new BUS architecture AMBA (Advanced Micro controller Bus Architecture). This architecture ARM920T separates Data Cache and Instruction Cache ,each Cache lines are in the 8 bytes in length, with respectively 16KB of space. In the production process, the macro-cell and memory cell use a CMOS standard of 0.13μm . S3C2440 provides a nearly complete generic peripheral pin, so there is basically no need to configure additional components.As a supplement to the wired network, wireless local area network uses radio frequency technology (Radio Frequency RF) to replace the twisted pair cable network, allowing the network terminals in the network signal to move freely within the coverage area without complicated network of wiring, saving resources also bringing convenience.Under the standard of the 802.11b / g wireless LAN, transmission rate is close to Ethernet, and each node in the wireless AP allows access to 100 or so users of the bridge in a number of AP, the network coverage can also be expanded to tens of kilometers. Its strong mobility, anti-interference, safety , network speed, expansion capability and resistence to topographic influence laid the foundation for future development.Streaming media learns from the computer CPU processing documents and uses a buffer to resolve the pending issues. Multimedia information uses a remote network of technology-specific division to pack compression and perform real-time transmission to the broadcast side of the buffer zone so that the player-side does not need to wait for the end of the entire multimedia file transfer but can extract the file within the buffer zone to re-play,thus greatly reducing the waiting time for multimedia transmission. In space utilization, the buffer can abandon the media data that has been played to leave space for the new stream of data. It also makes sure that the multimedia data that has been played left no copy at the terminal, thus protecting copyrights.This thesis analyzes the transmission of streaming media suitable for Real-time Transport of Protocol RTP / RTCP. It is transmitted over the Internet real-time audio and video media, defined in documents as early as in 1991, published by a laboratory in the United States. In 1996, the Working Group of IETF video / audio has developed the standard version of Real-time Transport Protocol RTP. RTP protocol is designed to solve the real-time streaming media transmission, compared to the original network of widely used transport protocol-oriented transmission that emphasizes on data integrity and security, RTP protocol is more inclined to the flow of information in real time, and it loses a lot of quality control of the transmission of information. It is lightly armed with a set of data, combined with auxiliary RTCP control protocol, as the transport layer protocol to complete the encapsulation of streaming media data transmission.RTCP protocol is used in conjunction with the RTP protocol for real-time transport control protocol;when the application procedure establishes a RTP session, it allocates two consecutive ports for RTP and RTCP separately, to enhance the flexibility of the protocol used. RTP protocol does not have the media synchronization so flow control and congestion control have to be achieved by the RTCP instead. QoS guarantee information is also carried by the RTCP packets, it can give the feedback of the sending and the receiving parties of the service quality of statistical information to the application procedure, and adjust the sending rate accordingly. RTCP protocol and RTP protocol are in the same protocol layer, both as UDP protocol data encapsulated into UDP packets. But because RTCP packets, compared to the control information data stream, are of much smaller amount of information, it is usually RTCP multiple data packets that are periodically packaged into a UDP packet for transmission to lower levels.With the understanding of the RTP / RTCP protocol based on the framework for system requirements, this thesis designed the streamlining of the RTP / RTCP protocol to allow more compact simple transport protocol packets. This frame format is designed for effective data transfer savings out of a network with more bandwidth.Finally, with the proposed the streamlining of RTP / RTCP protocol combined with RTP / RTCP protocol framework, the thesis thoroughly analyzed JRTPLib library, and made necessary amendments to adapt to the system applications. And the thesis also designed and implemented the terminal system of a wireless video streaming that can perform real-time monitoring when combined with the project of other modules.