The Design And Implementation Of Embedded Streaming Media Client In Vehicles

Passenger Information System, or PIS, is an integrated information system that provides subway passengers with arriving broadcast and various informations such as news and entertainment. At the same time, PIS plays an important role for surveillance and emergency noticing, under emergent situations such as a fire. Thus PIS may also be called Vehicle Multimedia Information System. With the development of networking and digital multimedia technology, VMIS is moving towards HD and digitalization. Terrestrial digital TV will also be introduced to meet passengers’ demands for real-time information. Therefore, this thesis proposes a design for the HD streaming media client based on Davinci, and has done some relevant tests successfully.Firstly, embedded streaming media and coding techniques are introduced. System requirements are analyzed. And a design scheme for an embedded streaming media client for use with ethernet is proposed.Secondly, a multi-threading design is introduced, after proposing concrete system hardware and software design schemes combining with practical.Thirdly, combining with embedded Linux development procedure, this thesis introduces the constructing process of system development environment, including the construction of cross compile environment and transplantation of the kernel, bootloader and filesystem.Fourth, based on the execution process of threads, starting with the reception of data streams, this thesis designs the communication protocol and realizes it using socket programming. Then the demuxing of audio and video data is done using FFmpeg open source library. The interaction and synchronizing methods of threads introduces as well.As MPEG-2is currently the main compression standard in the area of the terrestrial digital TV, starting with its encoding principles, this thesis proposes an encoding scheme, combining with the special software structure of Davinci, and then realizes it. Output display test is also completed.Finally, this thesis summarizes the completed work and research focuses. Room for improvement is pointed out. Prospects of future development of relevant technologies are proposed.