DMB Video Encoding Based On H.265

Digital Multimedia Broadcasting(DMB)is becoming more and more important due to its diversity of transmission content,better anti-interference and high spectrum utilization.It can play sound,video,picture and text at the same time.It has been applied in many schools and scenic spots.Due to the limited DMB bandwidth,video can only be transmitted at a low bit rate.The current video compression technology used in H.264 cannot meet the requirements of users in the low bit rate.In view of the above problems,this thesis proposes to use the latest H.265 video coding standard to compress video.Hence it can replace the current use of H.264 in order to improve the video quality.The specific work of the thesis is as follows:Firstly,the Frame and coding algorithm of H.265 video coding technology are studied.In addition,it optimizes the algorithm of key modules combined with the requirement of real-time and code rate of DMB system.Aiming at the problem that the H.265 encoding process takes a long time,the Sample Adaptive Offset is analyzed from the perspectives of the time domain and the spatial domain combined with the features of the human vision system that are interested in the texture complexity and the motion region.Moreover,the Sample Adaptive Offset algorithm has been optimized,tested and analyzed on the basis of that.Secondly,according to H.265 and DMB related standards,a modular design concept was adopted to design the decoding module,audio compression module,video compression module,and transport stream multiplexing module.Meanwhile,a DMB video encoder was designed in conjunction with multi-threading technology.Thirdly,the encoder was tested by the DMB transmission and test platform.The experimental results show that the average Sample Adaptive Offset coding time is reduced by 61.47% in the case of minimal loss of performance for the optimized Sample Adaptive Offset algorithm.In the DMB broadcast channel of 512 kbps code rate,through optimization of this algorithm,the H.265 encoded video stream,whose peak signal-to-noise ratio improved about 0.96 dB and the structural similarity increased by about 0.02,is compared with the video stream of H.264 encoded by DMB standard.