纹理-深度图共同优化的3D-HEVC帧内快速算法
A Fast Algorithm for Texture-Depth Co-optimization in 3D-HEVC Intra Prediction
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摘要: 随着立体及3D视频需求的日益增多,针对3D视频编码方法的研究受到越来越多的关注。3D-HEVC编码标准对采用纹理和深度图格式融合的3D视频进行编码,由于加入了深度图编码,因此新增了深度图编码模式、组件间预测和分段直流编码等技术,使其编码复杂度急剧升高。为了减少3D-HEVC的编码时间,本文提出了针对纹理图和深度图的编码单元(Coding Unit, CU)尺寸提前决策快速算法。利用梯度矩阵和作为当前CU和子CU复杂度的判断依据,将CU分为三类:不划分CU(Non-Split Coding Unit, NSCU)、直接划分CU(Split Coding Unit, SCU)以及普通CU。对NSCU,跳过小尺寸的帧内预测过程;对SCU,直接跳过当前CU的帧内预测过程;对普通CU,执行原平台操作。实验结果表明,与原始平台相比,本文算法在合成视点质量基本不变的情况下,平均减少40.92%的编码时间;与最新的联合纹理-深度图优化的3D-HEVC快速算法相比,可以在质量相当的情况下减少更多的编码时间。Abstract: With the increasing demand for stereo and 3D video, the research on 3D video coding has attracted more and more attentions. 3D-HEVC standard is for 3D video coding with texture and depth map format. Due to the addition of depth map coding techniques, the coding complexity increases dramatically. Therefore, a fast intra coding algorithm for both texture and depth maps in 3D-HEVC was proposed. First, CU was divided into three categories: Non-split Coding Unit (NSCU), Split Coding Unit (SCU), and ordinary CU, by using the Sum of gradient matrix (SGM) as the complexity judgment basis of current CU and Sub-CU. For NSCU, the small size of the intra-frame prediction process was skipped; for SCU, the intra-frame prediction process of the current CU was skipped directly; and for ordinary CU, the original platform operation was performed. Experimental results show that compared with the original platform, the proposed algorithm reduces the coding time by 40.92% on average when the quality of synthetic viewpoints is basically unchanged. Compared with the state-of-the-art texture-depth co-optimization fast algorithms for 3D-HEVC, the outperformance of time saving is achieved with relatively equivalent quality.