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LoSA: Near-Lossless Sparse Attention for Training-Free Video Diffusion Acceleration

ai-technology · 2026-08-13

A new method called LoSA, or Near-Lossless Sparse Attention, has been developed to improve how video diffusion transformers work, and it doesn't require any retraining. This technique tackles the issue of high costs associated with self-attention in lengthy 3D token sequences, which can become more problematic with higher resolutions and longer durations. Unlike existing sparse attention methods that focus on extreme sparsity, LoSA keeps a threshold of 99% of the attention mass, ensuring nearly perfect fidelity. It’s based on two main ideas: around 40% of block interactions can be cut without losing attention mass, and the high-mass support remains stable during denoising. You can check out the research on arXiv with ID 2608.12032.

Key facts

  • LoSA is a training-free sparse-attention method for video diffusion transformers.
  • It fixes a retained-mass threshold of 99% instead of a sparsity ratio.
  • About 40% of block interactions can be removed while retaining 99% of attention mass.
  • The high-mass support remains stable across denoising steps.
  • LoSA measures exact block attention masses at one early dense step.
  • The method targets the quadratic cost of self-attention over long 3D token sequences.
  • The paper is available on arXiv with ID 2608.12032.
  • The announcement type is cross.

Entities

Institutions

  • arXiv

Sources