Study On Rate Control Technology Based On H.264/AVC

The new generation of video coding standard H.264/AVC make compression efficiency doubled, however, the rate control is become more complicated.The H.264/AVC video coding standard contain better performance than old standerds,for example, under the same video quality, the bitrate for H.264/AVC can reduce about half;Under the same bitrate, H.264 video compression coding standard can obtain higher signal-to-noise ratio. The rate control and rate distortion is one of the two key technologies for H.264/AVC video coding standard, which has complicated and close relationship.Rate control technology in video compression can include in the framework of video coding or not, the rate control algorithm is open, which adopted by applications or not according different occasion.But rate control has an important role on the quality of the video compression, bitrate control, buffer control.Reasonable rate control can get a more reasonable balance between code quality, buffer control, rate control and jumped frame rate.Therefore, rate control technology is one of the important technologies on video coding.This paper introduced some key technologies for new generation video compression standard for H.264/AVC first,such as inter/intra prediction、entropy coding、discrete cosine integral transform and so on.Then introduced the rate control algorithm for H.264/AVC、the relation between rate control algorithm and rate distortion、the classical rate control proposal of JVT-G012 and so on.The main content as follows:(1) The video sequence is generally not made up of a single scene,but contain different scenarios such as Multimedia video.When scene switching appear in the video sequence, the correlation between frames greatly decrease, therefore the traditional rate control strategy may lost its efficacy to deal with scene switching.As a result,in order to solve this problem,a method to process scene switch is put forward in this paper.First,detection scene switching with PSNR,and then proposes GOP(Group of Pictures)restructuring methods but also the rate update method and the quantitative parameter calculation.(2) An adaptive GOP length rate control technology is proposed in this paper, which is applicable to handle video sequence contains frequent scene changes. First,detection scene switching with PSNR, then the unencoded frames in the current GOP will average assigned to the following two GOPs and redistribution rate and adjust the quantitative parameters for the I frame. As the number of I frames does not increase in the algorithm, thus obtained a good effect in bitrate control.