Study On Improved Algorithm Of X264for Computer Analog Transmission Images

With recent development of Consumer Electronics and network media technology, video compression technique has been widely used and thus become the focus of research activities. International Telecommunication Union (ITU) and International Standardization Organization (ISO) have established a series of video compression coding standards, including H.26x and MPEG-X respectively. Among the above mentioned standards, H.264/AVC is currently most widely used one. Developed by joint effort of ITU and ISO in2003, it takes advantage of previous versions and makes great leap in terms of compression rate and network adaptability.JM and X264are two main open source implementation of H.264/AVC. JM is suitable for research on the coding algorithm, as it completely incorporates all details specified in H.264without consideration on implementation efficiency. X264, on the contrary, fully considers efficiency by replacing the time-consuming parts with assembly and by adding some optimization algorithms. Therefore, X264is more frequently used in engineering applications.he computer analog transmission images/videos here refer to the screen content transmitted in an analog channel for video conference applications, which typically include computer operation and slide show. The thesis further improves X264based on the features of computer analog transmission images/videos, reduces the bit rate and increases the coding speed. TThe work in the thesis contains three parts as below:(1) For given GOP input parameter in video conference applications, IDR is avoided and replaced by P frame through checking the structural similarity between current frame and temporal neighbors.(2) Considering the zero mean Gaussian noise introduced in the analog transmission of computer screen images, a novel t testing P_SKIP mode decision is developed.(3) According to possibility of occurrence of P8x8, P16xl6and116x16mode is regarded as main mode, whereas other inter modes are taken as affiliated to PI6x16and14x4to116x16. By comparing the encoding cost of P16x16and116x16, a decision on inter/intra mode is made in advance.