APSIPA Transactions on Signal and Information Processing > Vol 14 > Issue 2

Enhanced MPEG G-PCC: Addressing Challenges in the OBUF Entropy Coding Framework

Xiao Huo, Xidian University, China, xhuo@stu.xidian.edu.cn , Shidi Hao, Northwestern Polytechnical University, China, Wei Zhang, Xidian University, China, Fuzheng Yang, Xidian University, China
 
Suggested Citation
Xiao Huo, Shidi Hao, Wei Zhang and Fuzheng Yang (2025), "Enhanced MPEG G-PCC: Addressing Challenges in the OBUF Entropy Coding Framework", APSIPA Transactions on Signal and Information Processing: Vol. 14: No. 2, e102. http://dx.doi.org/10.1561/116.20240054

Publication Date: 23 Apr 2025
© 2025 X. Huo, S. Hai, W. Zhang and F. Yang
 
Subjects
Coding theory and practice,  Data compression,  Rate-distortion theory
 
Keywords
point cloud compressioncontext modelinter-frame coding
 

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In this article:
Introduction 
OBUF in G-PCC 
Proposed Method 
Experimental Results 
Conclusions 
References 

Abstract

The Moving Picture Experts Group (MPEG) has published the geometry-based point cloud compression (G-PCC) standard. It converts the compression of irregular point coordinates to the coding of structured binary octree node occupancy, where the Context-based Adaptive Binary Arithmetic Coding (CABAC) can be applied. The context model, constructed by intra and inter-octree layer information, drives the probability update of the arithmetic coder with a so-called Optimal Binarization with Update On-the-Fly (OBUF) scheme. The original OBUF design, while effective, lacks a probability range limitation for each binary coder, leading to issues in probability estimation accuracy and convergence speed. Moreover, when coding dynamic point clouds, the inter-frame information is not efficiently considered in OBUF, leading to excessive memory consumption for storing and tracking context states. To address these challenges, we propose an initialization strategy for both fine-grained context states (Fine-CtxS) and coarse-grained context states (Coarse-CtxS) in OBUF, alongside an adaptive probability bound determination method for each Coarse-CtxS to confine probability estimation. Furthermore, the paper delves into improvements for inter-frame geometry coding, including the construction of Fine-CtxS, and reducing memory consumption of Fine-CtxS in OBUF. The proposed methods have been adopted in recent G-PCC Edition 2 standardization activities, demonstrating enhanced performance.

DOI:10.1561/116.20240054

Companion

APSIPA Transactions on Signal and Information Processing Special Issue - Three-dimensional Point Cloud Data Modeling, Processing, and Analysis
See the other articles that are part of this special issue.