The Optimization Of Video Coding Algorithm Based On Parameters Selection

Video coding optimization research has been the hot spot in the field of video coding. How to balance the rate-distortion performance and coding complexity to meet specific application requirements become an important research direction in video coding optimization. With the constantly development of multi-media technology, video coding technology has been mature so that video coding optimization based on improving the coding technology is very difficult. X264 as a H.264/AVC encoder has been widely used in industry, and includes a large number of coding parameters which execute the coding algorithm. Each coding parameter has different options, and the different options have critical implications for performance and complexity. Considering the previous video coding optimization from the point of video coding technology, did not pay attention to the nature of the video coder. Consequently, we can achieve the video coding optimization based on the coding parameters.How to select out the coding parameters which significant effect on the coding performance from numerous coding parameters and establish a candidate value list with a certain degree of differentiation and sensitivity are the primary problem.According to the rate-distortion performance of coding parameters’ options, based on the ?PSNR between different option, we formulate the evaluation standards of dominant coding parameters. Considering the different coding parameters types, set up the candidate value list. For the coding parameters of continuous values, based on the PSNR curve’ gain to zoning, and set up the nonlinear interval values in different locale to obtain the corresponding candidate values.Video coding optimization is under the constraint of rate-distortion performance and complexity, so the measurement of rate-distortion performance and complexity become one of the important research content. Due to the difficulty of real-time access to the rate-distortion performance, we employ the offline test method to deal with bitrate and distortion at the end of coding processing. Based on the area integral of distortion within the target bitrate to measure rate-distortion performance.Combining the video image signal and MSE, we have put forward the objective video quality evaluation method. Using orthogonal experiment design method,establish the rate-distortion-complexity optimized model to find out the optimal mapping relation between rate-distortion and complexity, and provide forceful support for coding parameters optimization.Dominant coding parameters’ different candidate value has different influence on coding complexity and rate-distortion performance. Based on variation of rate-distortion performance in unit complexity between adjacent candidate values,we put forward coding parameters optimization method with the highest coding cost performance. This method on the basis of coding parameters decision priority,through the coding parameter adaptive disturbance comparison between adjacent options to complete the selection of coding parameters option. Experimental results show that this optimization method can configure the coding parameters combination with highest rate-distortion performance in unit coding complexity under a certain coding complexity or rate-distortion performance constraint, and achieve the purpose of video coding optimization.