结合时空梯度感知特征的HEVC-SCC码率控制算法

Rate Control Algorithm for HEVC-SCC with Perceptual Features of Spatial and Temporal Gradient

针对屏幕内容视频具有大量文字、图形区域以及锐利边缘的特点,本文在HEVC-SCC编码标准上提出一种结合时空梯度感知特征的HEVC-SCC码率控制算法。考虑把有效的码率用在对于人眼视觉系统更加敏感的特性上,本算法主要从空域和时域两方面进行屏幕内容视频感知特性的提取。在空域方面,采用差分算子提取梯度幅值信息,得到空域特征的描述子;在时域方面,采用可以较好描述屏幕内容视频感知特征的梯度相似性度量信息,结合相邻帧间的相关性,得到时域特征的描述子。将时空梯度感知特性进行融合,用以控制屏幕内容视频编码的码率。实验结果表明,在随机接入模式下,本算法和原始HEVC-SCC算法相比,在略微降低误码率、节省码率开销的同时提高了视频的感知质量。

Based on the large number of texts,graphics areas and sharp edges characteristics in screen content video,a rate control algorithm for HEVC-SCC with perceptual features of spatial and temporal gradient is proposed in this paper.Considering that effective bitrates should be used to the features that are more sensitive for human visual system,the perceptual features are extracted from spatial and temporal domains.In spatial domain,a difference operator is used to extract the gradient magnitude information and obtain the descriptor of spatial features.In temporal domain,gradient similarity measure information is used,which can better describe the perceptual features of screen content video.Combining the correlation between adjacent frames,the descriptor of time domain features is obtained.The fusion of these features is used to guide the rate control of HEVC-SCC.Experimental results show that,in random access mode,compared with the original HEVC-SCC,the perceptual qualities of videos are improved with the reduction of bitrate error.