摘要：

在自适应码率视频直播过程中,传统码率控制方法不能有效控制切片码率,导致客户端播放器自适应判断失准,出现卡顿。为此,提出一种切片层级的码率控制算法。在切片内部使用基于帧类型的码率分配策略,提出关键P帧的概念,通过调整关键P帧的分布来优化不同视频内容下的码率分配。建立基于SATD和量化系数的线性预测模型,利用模型迭代调整每行的量化系数,进而控制整帧的编码大小。实验结果表明,该算法可以准确控制切片码率,保证视频质量。

关键词: 视频直播, 自适应码率, 视频编码, 码率控制, 量化参数

Abstract:

As traditional rate control methods cannot effectively control the segment size in adaptive bit-rate live streaming,the bitrate adaption of video player is affected by the fluctuation of segment size,and then makes inaccurate decisions,resulting in the delay on the client side.To solve this problem,a segment level rate control algorithm is proposed.Bit allocation strategy based on frame type is used inside each segment.The concept of key P-frame is proposed and the distribution of key P-frame is adjusted to optimize the allocation under different video contents.At the same time,a linear prediction model based on SATD and Quantization Parameter(QP) is built,and the QP of each row is adjusted iteratively to control the coding size of the whole frame.Experimental results show that the proposed algorithm can control the bit-rate of segment precisely and ensure the video quality.

Key words: live streaming, adaptive bit-rate, video coding, bit-rate control, Quantization Parameter(QP)

中图分类号: 

• TN919.8