Algorithmic Research Of Wireless Video Coding And Implementation With DSP Based On The H.264

With the rapid development of wireless communication technology and the increase of wireless networks bandwidth , it is possible to transmit multimedia content in mobile circumstance. Video communication is the kernel of multimedia operation because vision is the most important information media of human being. On the other hand, the transmission of video content over wireless networks poses big technical challenge duo to the specific characteristics of wireless channel such as high bit error rate, it becomes a hotspot for the research!Video display needs well timeliness, this requires the sufficient bandwidth, guaranteed time lag and the bit error rate. In order to replay the video , we need at least 28 Kbits bandwidth. Video transmission is very sensitive to the time lag, we must transmit the video signal from the sending terminal to the receiving terminal, or the video will not display glibly and continuously, so the quality of the video will drop. But mobile network couldn't provide credible services.For the wireless channels, the available bandwidth is limited. Due to the multipath effect, multipath delay, multipath fading and some other reasons, the mobile communication has the characteristics that its bandwidth is undulate and high bit error rate, so some continuous and gusty error of transmission usually appears. The reliability of the transmission decrease because of the available bandwidth and the transmission rate are time-variant.Based on the challenge of the wireless video communication, this paper dose some research on the H.264 , especially on how to well control error diffuseness and drop the complexity of coding as well as how to realize the H.264 coding with DSP.In order to reduce the time of the P-frames mode decision in H.264, this paper proposes an improved algorithm, to divide the video sequence into the background areas and the motional areas, and meanwhile to use the blocks: 16×16,16×8,8×16,8×8 and 4×4 of seven blocks,the experiment results indicate that this method could save lots of time for coding and increase the coding efficiency.We do some research on the SP-frames and further on we bring forward a new thought CSWI that which can well control error diffuseness, and simulation results prove that it is better than the way of single using SP-frames to replace I-frames. Compared with the previous video standards, H.264/AVC use multi-Reference frame technology, for the features of low bit rate video communication, we test the coding efficiency and Error resilient performance of the multi-Reference frame technology in H.264. Experiments show that reducing the number of the reference frames can effectively improve the coding efficiency and error resilient performance for the low bit-rate video communication.Based on the research of the hardware of the TMS320DM642 and the X264, we make use of the DSP to encoding the video signals. By means of collecting, compressing, and decoding through JM86, we know that this method could real-time encoding the video signals. In this coding technique,motion estimation takes up most of the time, so the optimization of motion estimation is a key problem for the improvement of coding efficiency.