Guidance Is a Field, Not a Scalar: Interval-Integrated Classifier-Free Guidance for One-Step Video Generation
Organizations: Peking University
Abstract
One-step generators built on MeanFlow synthesize a video in a single function evaluation, yet inherit a rigid treatment of classifier-free guidance (CFG): the guidance scale is frozen during training or, at best, exposed as a single scalar. This conflicts with mounting evidence that the optimal guidance is not a constant but a field that varies with the noise level, with spatial content, and, for video, with frame position. Every existing remedy presupposes a multi-step sampler along which guidance can be re-scheduled--an assumption one-step models violate by construction. We resolve this tension through a single observation: because the MeanFlow target is an integral over a noise interval, an arbitrary guidance field can be absorbed into the target itself and compiled into one evaluation. We formalize this as the interval-integrated CFG identity, prove that the compiled guidance carries no schedule-discretization error and can thus match or exceed any finite multi-step sampler, and instantiate it as AGAVE, which equips the average-velocity field with a learnable temporal schedule, a free motion-saliency spatial modulation, and a frame-position asymmetry. Adding fewer than ten scalars at zero inference cost, AGAVE surpasses all one-step baselines on VBench, UCF-101 and MSR-VTT while matching multi-step guided sampling. Project repository: https://github.com/YMlinfeng/AGAVE.
Figures & tables
| Method | NFE | Total | Quality | Semantic | Subj. Cons. | Bg. Cons. | Motion Smooth. | Dynamic Degree | Aesth. Qual. |
| 14B backbone | |||||||||
| Wan2.1 teacher [ 40 ] | 50 | 84.0 | 84.9 | 80.4 | 95.0 | 96.3 | 98.2 | 54.0 | 63.0 |
| rCM [ 49 ] | 4 | 85.0 | 85.6 | 80.9 | 95.3 | 96.5 | 98.4 | 53.5 | 62.9 |
| rCM [ 49 ] | 1 | 83.0 | 84.0 | 78.2 | 94.1 | 96.7 | 97.6 | 47.5 | 60.2 |
| MeanFlow CFG [ 8 ] | 1 | 83.3 | 84.2 | 78.7 | 94.3 | 95.9 | 97.7 | 49.0 | 60.8 |
| CFG-Zero ⋆ (1-step) [ 6 ] | 1 | 83.6 | 84.4 | 79.0 | 94.6 | 96.0 | 97.9 | 50.3 | 61.3 |
| Method | NFE | UCF FVD | MSR-VTT FVD | CLIP -T | Par. Lat. |
| Wan2.1 teacher | 50 | 380 | 268 | 0.305 | 50 |
| rCM (4-step) | 4 | 372 | 262 | 0.307 | 4 |
| rCM (1-step) | 1 | 495 | 348 | 0.290 | 1 |
| iMF | 1 | 441 | 318 | 0.298 | 1 |
| AGAVE | 1 | 372 | 261 | 0.309 | 1 |
| Guidance | NFE | VBench | UCF FVD | Over- sat. |
| CFG (fixed) [ 10 ] | 50 | 84.0 | 380 | 0.21 |
| APG [ 33 ] | 50 | 84.1 | 377 | 0.14 |
| -CFG [ 22 ] | 50 | 84.2 | 375 | 0.15 |
| CFG-Zero ⋆ [ 6 ] | 50 | 84.3 | 372 | 0.13 |
| AGAVE | 1 | 85.2 | 372 | 0.10 |
| Configuration | VBench | UCF FVD | CLIP-T |
| constant (= iMF) | 83.0 | 464 | 0.298 |
| + step gate (CFG-Zero ⋆ ) | 84.2 | 428 | 0.300 |
| + linear ramp | 84.2 | 419 | 0.301 |
| + Beta (fixed) | 84.7 | 414 | 0.301 |
| + Beta (learned) = I 2 - CFG | 84.9 | 391 | 0.305 |
| + motion-saliency | 85.1 | 380 | 0.307 |