中文摘要：

JVT—H017是H．264视频编码标准中采用的码率控制算法提案，但在许多实时场景应用中该算法还存在平均绝对差值（MAD）预测不准确等一些不足。针对现有码率控制技术的缺陷，提出一种改进的基本单元层码率控制算法，一方面在基于图像复杂度和运动信息的基础上采用了4种时空加权模型预测平均绝对差值，并且采用运动矢量信息对图像复杂程度进行判定；另一方面结合MAD的变化情况分配目标比特。实验结果表明，相比于JVT—H017和一些新的文献算法，改进算法的编码图像峰值信噪比得到了提高，同时实际码率更接近于目标码率，码率控制性能更优越。

英文摘要：

In view of drawbacks of existing rate control algorithms, an improve rate control algorithm for H. 264 is proposed. On the one hand, four novel weighted models using both temporal and spatial information are proposed to predict the MAD of different motion intensity. On the other hand,the changes of MAD are adopted to represent the image complexity,and used as a coefficient of the target bit allocation. Compared with algorithms of JVT-H017 and references, the bit rate of proposed algorithm is closer to the target bit, and the average of peak signal to noise ratio is improved.