Design And Realization Of H.264-based Embedded Real Time Video Acquisition And Transmission System

With quick development of communication and multimedia technology, high-quality video transmission has been gradually replacing traditional voice and text communication and becomes the main expanded service of digital communication network. At the same time, the continuous development of microelectronics technology and embedded operating system has created favorable conditions for implementation of embedded multimedia communication terminals. Mutual integration of Embedded Technoloy, Network & Communication Technology and Multimedia Technology will become the developing trend of digital video communication field. As the bandwidth of embedded digital communication system is limited, the previous video compression technology is not conducive to real-time transmission of high-quality live video.In order to transmit high-quality video images through more narrow network bandwidth, a new generation of video coding standard H.264/AVC has been promulgated by the Joint Video Team(JVT) of ITU-T Video Coding Expert Group(VCEG) and ISO/IEC Moving Picture Experts Group(MPEG). H.264 standard introduces a series of advanced video compression coding techniques to effectively improve encoding performance, but also dramatically increases the computational complexity, which becomes a major constraint for its use in embedded video applications. Therefore, the research on achieving H.264 video compression of high computational complexity in embedded systems is extremely challenging. However, the H.264-based embedded real-time video communication systems solution is still in exploring stage.This dissertation aims at developing an H.264-based real-time video communica--tion terminal on an embedded platform. In this dissertation, based on the PXA270 Liod development platform, combining embedded Linux technology and H.264~based video communication technology, a real-time video acquisition and transmission system solution model based on an embedded video server is provided. It provides reference significance and practical value for the actual embedded video communication systems design and development.The author's work and innovation include:1. in-depth study of embedded Linux development technology, and embedded Linux platform building based on Liod development board, including cross-compiling environment building, Bootloader design, Linux 2.6.22.6 kernel porting, device drivers development, and Busybox-based root file sytem construction.2. research on real-time video capture technology based on Video4Linux, including USB camera driver development and real-time video capture application design.3. proposing an application-oriented embedded real-time H.264 video compre--ssion coding sheme, and research on multimedia application program optimization methods based on embedded microprocessor architecture. Compile-time optimization and Code-level optimization is applied to open-source encoder x264, to achieve the real-time application requirements.4. research on H.264 video transmission technology in EP-based network, design of Server/Client service programs for video communication terminals, and implemen--tation of an embedded real-time video acquisition and transmission system model with VLC(VideoLan Client).