Research On The Real-time Mobile Video Technology Based On H.264

In the past three decades, mobile communications and multimedia communications received fast development. Mobile communications and multimedia technology integration is accelerated. Real-time mobile video with a higher challenge requires media packets to arrive in a timely manner-excessively delayed packets are useless and are treated as lost. Real-time mobile video technology in social security monitoring, video conferencing has a wide range of applications, has become a hot topic in multimedia communications.The paper comprehensives Zhongshan Mobile "service room video surveillance network management platform" project, adaptive transmission for mobile video QoS (Quality of Service) control, and audio and video synchronization strategy conducted in-depth research.For constantly changing wireless network bandwidth issues, based on dynamic frame rate adjustment of congestion control algorithm is proposed. The algorithm is based on the network jitter, packet loss and delay determine the state of the network, then control the video frame rate, video bit rate to adapt to the current network status. In order to ensure that the rest of the frame after frame rate adjustment maximum response to the video content, this paper, based on spatial color histogram of non-uniform sampling the video frame rate adjustment algorithm is proposed. In the algorithm, the color histogram with spatial information, quickly and efficiently extract feature vectors for each frame, feature vector selection under the most representative profile of the frame video content. Video for wireless networks easy to makes mistake. NALU (Network Abstract Layer Unit) layer and the GOP (Group Of Pictures) layer of non-equal joint protection algorithm is proposed in the paper. The algorithm is simple, robust and good.In order to solve the problem of multimedia asynchronous, the paper proposes a distributed clock synchronization strategy for mobile audio and video. The paper introduces the virtual clock based on the timeline synchronization model. The adjustment of the virtual clock is driven by the measured synchronization phase distortion and loss ratio, and appears in the form of expanding or shortening the play duration of one media data unit, or proactively skipping late data. This scheme is able to strike a dynamic balance between the synchronization and the end-to-end latency requirements in real-time and achieves synchronization on intra-media and inter-media.Finally, system testing and application results are described. The result shows that, despite the constantly changing state of the wireless network, this program can auto adjust the frame rate and recover the errors. Image PSNR (Peak Signal to Noise Ratio) is over 20dB, the average PSNR is 25.7dB. The proposed synchronization scheme outperforms a static delay scheme in terms of a reduction in the average latency by around 450 ms for the same amount of media data unit losses and the synchronization phase distortion is acceptable. The results can be seen from a practical application, this algorithm can achieve good results.