Dsp-based Network Streaming Media Playback System

With the development of multimedia and internet technology, the stream media communication on the network has become a necessary of the multimedia communication. We can reduce the data quantity making use of the coding and decoding algorithm for the audio and video, so that we decrease the bandwidth request of the network transmission, in order to assure the real -time request, the real time realization of the algorithm becomes a key problem. It is easy to upgrade and transplant using the pure software method, but the real-time capability can't be satisfied. Using the special codec can satisfy the real-time capability, but the flexible capability is not good and it goes against the algorithm upgrade. The TMS320DM642 (for short DM642) which is designed by TI Corporation solves the questions above successfully.The TMS320DM642 Digital Media Processor is considered to work well for people who use DSP at present. It is based on the C64x CPU, which is part of the C6000 DSP family. The DM642 integrates a number of peripherals to address the development of video and imaging applications, such as video port, EMAC and so on. Its entire programmable capability makes it compatible to all kinds of multimedia processing standard and form a universal software platform. It has become an effective approach that combines software and hardware method which make the embedded processing chip as the core processor.The system realizes single channels video stream transmit on the internet and realtime decode play using two pieces of SEED-VPM642. The system has following characters: (1) the use of Digital Media Processor not only ensures the real-time realization of the system, but also the flexible of the algorithm. (2) The use of H.263 XDAIS algorithm from TI avoids the algorithm optimize which improves the development efficiency. User only needs to know the interface of the algorithm. (3) The framework of the system is clear and understandable, so the H.264,MPEG4,G.729 algorithms can be transplanted to the system easily. The system framework can work as a standard framework for the system development of the DSP which belongs to the TMS320C6000 series. And if the audio and video algorithms combined based on the multimedia communication system standard protocol-H.323, the system can establish the foundation for the IP video phone. (4) The development of network function which uses NDK can apply the usual method for network development to the DSP development. It avoids the complicated hardware research, and improves the efficiency greatly.In this paper, the development of network stream media play system with DM642 and H.263 XDAIS algorithm has been introduced. In the research process, the following work has been done. (1) The structure and principle of the hardware platform of DM642 have been studied. (2) The framework RF5 which is regular used in the development of TMS320C6000 series DSP has been researched. Then constructs the framework the system needed. (3) The principle of H.263 XDAIS algorithm and the approach to use have been studied, then transplant the algorithm to the system framework to realize encode and decode of the digital video. (4) The NDK which is used to add the network function for the TMS320C6000 DSP has been studied in detail, and the network communication function using the EMAC of DM642 is realized.At present, the system has accomplished the real-time network play of single channels video; the system model can be used not only on the region monitor based on the LAN, but also on the long-distance monitor through internet. This system can be served as a network video monitor system universal platform.