中文摘要：

针对HEVC视频编码中帧层比特分配和率失真模型参数自适应更新，提出了一种改进的码率控制算法。该算法引入牛顿法来自适应更新率失真模型的参数；同时提出一种帧层复杂度度量方法，利用图像自身的内容特性来调整帧层比特分配；最后在编码过程中选择合适的量化参数。实验结果表明：与参考算法比较，该算法能大大降低计算复杂度，同时保持良好的码率控制性能，对含有场景突变的视频改进效果尤为明显。

英文摘要：

In view of HEVC video coding frame-layer bits allocation and parameters of rate-distortion model adaptively updated, an improved rate control algorithm is proposed. It adaptively updates rate-distortion model parameters by Newton method. In the meanwhile,it adopts a frame-layer complexity metric method and takes full advantage of image content features to adjust frame-lay- er bits allocation. Finally, the appropriate quantization parameter is selected during the encoding process. The results show that： compared with the reference algorithm, the proposed algorithm greatly reduces the computational complexity and achieves a good rate control performance, particularly for video sequences containing scene changes.