关键词: 高性能视频编码, 帧内预测, 四叉树结构, 平滑区域检测, 快速算法

Abstract:

Based on the quadtree structure of the HEVC coding unit, a fast intra coding algorithm that skips splitting subblock is proposed according to the result of the smooth region detection to reduce the intra coding complexity. First, the relationship between the image smoothness and coding unit's size has been analyzed by counting statistically the distribution of corresponding final coding units' sizes selected under different quantization parameters for different video contents. Second, whether the current coding unit belongs to the smooth region is detected according to the coding information on the current coding unit, which can help determine how to adaptively skip the coding process of the coding unit sizes not suitable for the texture features. Experimental results on the latest HM4.0 show that, on average, compared with the default fast approach set in the HEVC reference software, the proposed algorithm reduces the computational complexity by 24.8％ and 18.6％ for Low Complexity (Loco) and High Efficiency (HE) test sets, respectively, while incurring only 0.44％ and 0.12％ increment on the total bit rate, at the same peak signal to noise ratio (PSNR), which is of great practical value.

Key words: HEVC, intra prediction, quadtree structure, smooth region detection, fast algorithm