Research And Implementation Of Embedded Stream Media Player Based On ARM

With the rapid development of computer network, the high-speed integrated circuit, audio video compress technology, the realization of multimedia application such as Video-phone, Video on Demand, Real-time Video Conference, and Distance Education using portable movable devices has been eagerly needed. The stream media and the embedded system technology is the most significance in this field. The paradox between mass of multimedia data and shortage of resource on embedded device promote the development of embedded stream media application. Lastly, the multimedia has been wildly used in entertainment, working, learning aspects because of its lively, vivid, and direct. So search on embedded stream media is significant and promising.Owing to exist of varies codec international standards, network transport protocols and embedded system platforms, it's impossible that one solution can suit to every stream media application without any changes. Smart residential area monitor, for example, should pay less attention to the real-time and portable than the video-phone on mobile device. Vice visa, video-phone shouldn't focus on excessively the quality of the image compared to its counterpart. So, compromise and cooperation among network, codec arithmetic, and embedded system is necessary to optimize special implementation.Based on "Everything Over IP" philosophy, combined with the characteristic of wire or wireless data link layer this paper focuses on transfer media data on RTP/RTCP via UDP. With the development of SoC, many Micro Processing Unit could decode complex media data without assistant of special hardware such as DSP, FPGA, so the S3C2440, which has a arm9 core, is served as embedded CPU. In addtion the linux2.6 is transplanted on this platform so that multi-thread program is supported. this essay mainly talks about how the mp3 and H.264 file are transferred to embedded platform, and how the embedded device decode the media stream and play.1, considered the bitrate, frame format of mp3, and the "best effort" characteristic. This essay realize the loss-tolerate mp3 stream player that is more efficient in subjective acoustical quality. In the first the MP3 frame was parsed and packed in interlaced way. Then embedded platform decodes the MP3 stream with libmad mp3 decode engine. Last, the PCM data are sent to OSS driver.2, after prudent analysis on complexity of H.264 decode, the implementation supports H.264 baseline profile. By means of NAL layer of H.264, the encode streams are packed in STAP way, and transfer to embedded platform along with parameter set. then this stream data are encoded on embedded device. Finally this decode streams are send to FrameBuffer.