AST-ToMe: adaptive step-aware thresholding for efficient temporal-spatial feature reuse in diffusion models

Abstract

The exceptional generative capabilities of modern diffusion models are fundamentally bottlenecked by the quadratic computational complexity of their attention mechanisms. While recent feature caching strategies attempt to accelerate inference by skipping layers at static intervals, they fail to account for the non-linear evolution of latent features, inevitably causing severe structural distortions and temporal flickering. To address this, we propose AST-ToMe (Adaptive Step-Aware Thresholding), a novel dynamic gating mechanism that utilizes a runtime L2 norm feature drift metric to adaptively determine whether to compute or reuse attention states. Furthermore, we extend AST-ToMe to video stream generation through a cross-frame state inheritance design. Experimental results demonstrate that for single-image synthesis, AST-ToMe achieves a 15.3% reduction in inference latency with near-lossless perceptual quality (LPIPS: 0.0023). In continuous video generation, our method not only accelerates inference but also serves as a robust temporal anchor. By effectively suppressing random stochastic variations, AST-ToMe successfully reduces Temporal Jitter from 0.2059 to 0.1865, paving a highly efficient path for stable, flicker-free video generation.