| In Recent years, With the development of third generation cellular and the promise of wideband wireless connectivity technology, the video communication gradually became important part of communication. However, the error bit rate of wireless channel is higher than that of wire channel, because the error proneness, the time-varying and the bandwidth limit of wireless channel, as well as the fast fading and the slow fading for the Multi-path phenomena. At the same time, as a result of bandwidth limit, the video must be high compressed before transmitted, so the high compressed video is sensitive to transport error, a little of codes error maybe result in many codes undecoded correctly. Due to transmission efficiency, real-time, et al, in many application situation, some error control are not fit to video transmission, such as error correct code and repeat transmission, thus, we need to find more efficient error control method for video transmission.By systemic analysis of current international video code standard and error resilience, error correct, error concealment algorithm and encode method in the video communication system, A new method that adapt to mobile video transmission are summarized. The joint channel rate-distortion algorithm has been used in transmission system. This method use rate-distortion model and consider the mobile channel characteristic which based on the H.264 codec and real-time transmission protocol. And improved on the random macro-block refresh way in intra frame coding, the flexible macro-block ordering mapping technique and the adaptive packets-lost feedback. Experimental results show that it can obtain good video quality under the low bandwidth and high error wireless channel conditions.Considering the model of traditional mobile video communication system for error concealment. A novel error concealment algorithm is proposed by using the relativity of video in spatial and temporal, and by residue restoration based on MC concealment algorithm. This method is uncomplicated, simply realized and fit to mobile channel transmission. It can effectively improve mobile channel video properties compared with motion compensation error concealment algorithm. |
PDF Full Text Request