For reducing the variation between the actual bit rate, and target bit rate and improving the coding quality at the last coding frames, this paper proposed a new rate control algorithm to compensate the original rate control algorithm for SVC. Based on the correlation between frames and consideration of constant coding quality, it allocated bits evenly between GOPs (group of pictures). Besides, inside a GOP, it proposed an adaptive bit allocation on frame level based on coding complexity. Furthermore, taking appropriate adjustments on initial QP, then it calculated QPs for both P frames and B frames based on target bit respeetively. Experiments on different video sequences show that the proposed algorithm is accurate and effective.%为减少码率控制中实际输出码率与目标码率之间的误差,改善视频序列编码尾部质量下降的缺陷,同时针对可伸缩视频编码中码率控制算法的不足,提出一种自适应比特分配的码率控制算法.算法基于对根据相邻图像帧之间的相关性以及对恒定质量的考虑,在图像组(GOP)之间平均分配目标比特,而在GOP内部则根据编码复杂度自适应分配目标比特,同时适当调整初始量化参数(QP),再根据目标比特分别计算P帧、B帧的QP.对不同的视频序列进行了实验测试,其结果验证了算法的准确性和有效性.
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