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摘要
By considering the rate distortion optimization (RDO) characteristics, a multilevel optimal lambda decision algorithm for the rate control is proposed. With the process of getting the optimal lambda for the group of picture (GoP)-level rate control, the frame-level rate control, and the coding tree unit (CTU)-level rate control, a special relationship of the current level lambda and the next level lambda can be built. First, an approximate linear bit allocation relationship is used between the bit rate and the motion compensation prediction error to assign the bit rate more reasonably for every frame. Second, the multilevel optimal lambda decision scheme is proposed. To minimize the whole distortion of a sequence, an effective way is to get the optimal RDO of every GoP. Then, with the RDO process of the GoP-level rate control, an optimal frame lambda ratio for each frame in current GoP can be obtained. For the optimal frame lambda ratio, its value is mainly decided by the distortion effect, which is calculated by an employed source distortion propagation chain. Finally, an optimal CTU lambda clip scheme is proposed to get the optimal RDO of every CTU. The experimental results show that the coding quality of the proposed rate control algorithm is improved significantly with little loss of the bit rate accuracy.
- 出版日期2018-5
- 单位上海大学
