Fast Intra Coding of High Dynamic Range Videos in SHVC
Fast Intra Coding of High Dynamic Range Videos in SHVC
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SHVC 中高动态范围视频的快速帧内编码
DOI：
10.1109/lsp.2018.2867895
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发表时间：
2018-11-01
影响因子：
3.9
通讯作者：
An, Ping
中科院分区：
文献类型：
--
作者：
Fu, Guoliang;Shen, Liquan;An, Ping
与传统的标准动态范围（SDR）内容相比，高动态范围（HDR）内容通过提供高得多的亮度范围来为观看者提供更身临其境的体验。目前大多数消费者设备都无法承受这种新兴技术，内容提供商决定为同一视频创建HDR版本和SDR版本。在这封信中，可缩放高效视频编码（HEVC）HEVC的可缩放扩展（SHVC）用作编码框架，其中基础层（BL）是8-B SDR版本，并且增强层（EL）是12-B HDR版本。近年来，针对SDR视频提出了许多快速编码算法，并且迫切需要针对EL HDR视频的快速编码算法。结合BL SDR视频的编码信息，本文提出了一种降低EL HDR视频帧内编码复杂度的快速算法。首先，HDR版本中的相邻编码树单元（CTU）和SDR版本中的共位CTU的深度信息用于早期编码单元（CU）深度确定。此外，四个分类器被训练来预测CTU深度范围。针对具有高平均亮度的帧中的CTU训练两个分类器，并且针对具有低平均亮度的帧中的CTU使用另外两个分类器。实验结果表明，该算法实现了平均43%的编码时间节省，与原始SHVC测试模型相比，Bjøntegaard增量比特率（BDBR）仅增加了0.54%。
Compared with the conventional standard dynamic range (SDR) content, high dynamic range (HDR) content supplies viewers with more immersive experience by offering a much higher range of luminance. Most of current consumer devices cannot afford to this emerging technology, and content providers decide to create both an HDR version and an SDR version of the same video. In this letter, scalable high efficiency video coding (HEVC) scalable extension of HEVC (SHVC) serves as the coding framework where the base layer (BL) is an 8-b SDR version and the enhancement layer (EL) is a 12-b HDR version. Recently, many fast coding algorithms for SDR videos are proposed, and there is an urgent demand for fast coding algorithms for EL HDR videos. With the coding information of the BL SDR videos, this letter proposes a fast algorithm to reduce the complexity of intra coding for EL HDR videos. First, depth information of neighboring coding tree units (CTUs) in the HDR version and the colocated CTU in the SDR version is used for early coding unit (CU) depth determination. Moreover, four classifiers are trained to predict the CTU depth range. Two classifiers are trained for CTUs in frames with a high average luma, and another two classifiers are used for CTUs in frames with a low average luma. Experimental results show that the proposed algorithm achieves 43% encoding time saving on average, with only a 0.54% Bjøntegaard delta bit rate (BDBR) increase compared to the original SHVC test model.