PACE: Post-Causal Entropy Modeling for Learned LiDAR Point Cloud Compression

Jiahao Zhu; Kang You; Dandan Ding; Zhan Ma

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arXiv · 2605.01320

PACE: Post-Causal Entropy Modeling for Learned LiDAR Point Cloud Compression

Jiahao Zhu·Kang You·Dandan Ding·Zhan Ma

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Abstract

LiDAR point cloud compression is vital for autonomous systems to handle massive data from high-resolution sensors. While learned entropy modeling built upon octree structures yields high compression gains, it faces two critical bottlenecks: 1) prohibitive latency, particularly during decoding, caused by causal, multi-stage context modeling; and 2) a rigid performance-latency trade-off, preventing a single model from adapting to varying constraints. These limitations stem from the tight coupling between the context aggregation backbone and probability prediction. To address this, we propose PACE, a new framework that reformulates ancestral context aggregation as a non-causal backbone and confines causality to a lightweight, stage-scalable predictor, eliminating repetitive backbone executions and reducing computational overhead. The predictor supports an arbitrary number of prediction stages, enabling seamless adaptation across diverse performance-latency trade-offs without reloading parameters. Experiments demonstrate that PACE sets a new state-of-the-art in compression efficiency, achieving notable BD-BR savings and reducing decoding latency by over 90\% in autoregressive mode, making it attractive for practical applications.

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Jiahao Zhu, Kang You, Dandan Ding, Zhan Ma. 2026-05-02. PACE: Post-Causal Entropy Modeling for Learned LiDAR Point Cloud Compression. https://arxiv.org/abs/2605.01320

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