基于梯度的HEVC自适应码率控制算法研究

Adaptive rate control algorithm based on gradient for HEVC

针对新一代视频编码标准HEVC中的码率控制问题,提出了一种基于梯度的自适应码率控制算法。算法的主要特点是自适应获取每个LCU的梯度来表示其复杂度,根据复杂度分配LCU层目标比特。同时,在分配帧层目标比特时利用缓冲区的状态信息,以使编码器输出的实际码率更符合给定的目标码率,并使缓冲区滞留的数据尽量少,即传输时延尽量小。实验结果表明,该算法与标准的HEVC码率控制提案K0103相比,缓冲区滞留数据量平均减少约39.31%,峰值信噪比平均提高约0.54dB,同时实际码率与目标码率之间的码率偏差平均降低约0.39%。

Due to the problems such as rate control of the high efficiency video coding standard, an adaptive rate control algorithm based on gradient is proposed. In the algorithm, each LCU ＇ s gradient is adaptively obtained to represen its complexity, and then target bits depending on the complexity of the LCU is allocated. At the same time, in order to make the actual bits of each frame as closely as possible to the target bits, the buffer status feedback is used to minimize the delayed buffer data . The experimental re- sults show that compared with the rate control algorithm in HEVC standard, the delayed buffer data is reduced about 39.31%, the peak signal - noise ratio （PSNR） is increased about 0.54 dB, and the bitrate error is reduced about 0.39% on average.