Spherical Distortion Temporal Propagation and Spatial Mapping Model for Efficient Panoramic Video Coding

IF 3.2 1区计算机科学 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEE Transactions on Broadcasting Pub Date : 2024-02-19 DOI:10.1109/TBC.2024.3358749

Xu Yang;Minfeng Huang;Hongwei Guo;Shengxi Li;Lei Luo;Ce Zhu

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引用次数: 0

Abstract

Panoramic video undergoes projection onto a two-dimensional plane for compression and subsequent back-projection onto a sphere for display. This process introduces inconsistency between compression distortion and perceived spherical distortion, which causes a serious loss in coding efficiency. Meanwhile, the existing independent rate-distortion optimization (RDO) model for spherical distortion solely accounts for the current coding frame and neglects its influence on subsequent frames, which leads to sub-optimal coding performance. To this end, we propose a spherical distortion temporal propagation and spatial mapping model for efficient panoramic video coding. First, a zero-delay spherical distortion backward propagation chain is established in the temporal domain, and distortion impact factors are computed. Then, an accurate spatial mapping relationship between spherical distortion and coding distortion is constructed, along with the calculation of spatial mapping weights. Finally, these components are integrated into spherical RDO. The experimental results demonstrated the effectiveness of the proposed algorithm. Compared to the versatile video coding test model (VTM-14.0) with a 360Lib extension under low-delay P frame and B frame configurations, the proposed algorithm achieves bitrate savings of 9.4% (up to 19.4%) and 8.5% (up to 19.0%) by using WSPSNR as the distortion evaluation index, respectively. Additionally, the coding time was reduced by 14.53% and 15.65%, respectively.

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用于高效全景视频编码的球形畸变时空传播和空间映射模型

全景视频先投影到二维平面上进行压缩，然后再反投影到球面上进行显示。这一过程会导致压缩失真与感知球面失真不一致，从而严重降低编码效率。同时，现有的球形失真独立速率-失真优化（RDO）模型只考虑当前编码帧，忽略了其对后续帧的影响，导致编码性能未达到最佳。为此，我们提出了一种球形失真时间传播和空间映射模型，用于高效的全景视频编码。首先，在时域建立零延迟球形失真后向传播链，并计算失真影响因子。然后，构建球形失真与编码失真之间的精确空间映射关系，并计算空间映射权重。最后，将这些组件集成到球形 RDO 中。实验结果证明了所提算法的有效性。在低延迟 P 帧和 B 帧配置下，与带有 360Lib 扩展的通用视频编码测试模型（VTM-14.0）相比，以 WSPSNR 作为失真评估指标，所提算法分别节省了 9.4% （最高 19.4%）和 8.5%（最高 19.0%）的比特率。此外，编码时间也分别缩短了 14.53% 和 15.65%。

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来源期刊

IEEE Transactions on Broadcasting 工程技术-电信学

CiteScore

9.40

自引率

31.10%

发文量

审稿时长

6-12 weeks

期刊介绍： The Society’s Field of Interest is “Devices, equipment, techniques and systems related to broadcast technology, including the production, distribution, transmission, and propagation aspects.” In addition to this formal FOI statement, which is used to provide guidance to the Publications Committee in the selection of content, the AdCom has further resolved that “broadcast systems includes all aspects of transmission, propagation, and reception.”