The Principle And Design Of Deblocking Module In Video Compression Coding

With the rapid development of Internet and mobile communication, the processing and transporting technology of video information has become the central issue of China's informationization, and digital video technology has been used more and more widely. The issue of video compression coding should be settled before using, for video information contains large amounts of data. Nowadays, the main video compression coding standards such as H.264 and AVS are both based on the hybrid coding algorithm, and the coding error will cause apparent block effect when compression is large. The deblocking filtering technology can effectively remove the block effect and greatly improve the video quality, thus it is an important and practical technology.The paper focuses on the principle and design of deblocking filter module in video compression coding. First, it introduces the history of video compression coding, and describes several key technology such as predictive coding, transform coding, entropy coding and deblocking filtering. Then, it analyzes the reasons for block effect, which are the transform coding error from intra prediction and inter prediction on the one hand, and the discontinuity from motion compensation on the other hand. And there are two kinds of deblocking filter, one is post filter, and the other is in-loop filter. The H.264 and AVS video compression coding standards both use the in-loop filter for its advantages such as adaptivity, the saving of frame buffer and reduction of complexity.The deblocking filter design in this paper is based on the H.264 video compression coding standard. According to the function of the filter, the deblocking filter contains 11 units, which are deblocking control unit, pixels fetching unit, macroblock buffer unit, macroblock output unit, pixels row buffer unit, FIR unit, row buffer writing unit, parameters buffer unit, parameters row buffer unit, boundary strength parameters fetching unit and boundary strength computing unit.The innovation and improvement in this paper are as follows. First, the functions of the sub-modules are more concrete that it decreases the complexity of hardware implementation. Second, it increases the output efficiency by using a reasonable storing patten and changing of storing order. Third, it improves the filtering algorithm and rearranges the filtering order to decrease the access frequency of SRAM. Fourth, by using the local SRAM reasonably, this architecture greatly decreases bandwidth demand of the bus and increases the processing efficiency. The simulation shows that the blocking effect has been greatly eliminated, and the quality of the picture has been apparently improved after deblocking.At last, the paper indicates several possible development of deblocking filtering technology in the future.