When Distillation Breaks Motion Control: Restoring Generative Trajectories for Fast Video Generators

1Zhejiang University of Technology, 2UNSW Sydney, 3University of Auckland, 4Zhejiang University
*Indicates Equal Contribution. Indicates Corresponding Author.
Accepted to the European Conference on Computer Vision (ECCV), 2026

Reference Video (Zoom In)

"Railway for train."

Reference Video (Zoom Out)

"Man stands in his garden."

Reference Video (Orbit Shot)

"A island, on the ocean, sunny day."

Reference Video

"Explorer, walks on the desert."

Reference Video

"Leopard, slowly raises its head."

Reference Video

"A car is driving in a forest."

MotionEcho efficiency comparison

Abstract

Training-free motion customization imposes motion patterns from reference videos onto video generators through test-time computation. Most existing methods target full diffusion models, requiring many denoising steps and high computational cost. With the rise of efficient distilled models, a natural question arises: can test-time motion customization be applied directly to distilled generators with their accelerated sampling and efficiency gains? However, our analysis reveals that existing training-free techniques fail on distilled models. Distillation fundamentally alters the denoising dynamics that prior test-time guidance relies on, and the large denoising steps of distilled generators discard the dense intermediate states that score guidance requires, rendering existing motion control strategies incompatible with fast generation. To address this limitation, we propose MotionEcho, a novel training-free test-time distillation framework that enables motion customization for distilled video generators. The key idea is to correct the student model's sampling trajectory with restricted usage of a high-quality diffusion teacher at inference time. Teacher supervises the student's denoising by re-noising the student's endpoint onto its dense trajectory to form a motion-aligned clean endpoint, then interpolating it with the student's, while an adaptive scheduling mechanism determines when and how much teacher guidance is needed. As a result, MotionEcho restores generative trajectories for distilled video generators via lightweight, adaptive test-time teacher guidance, enabling accurate motion control without compromising generation efficiency. Extensive experiments on multiple distilled video generation models demonstrate that our method significantly improves motion fidelity and visual quality while retaining the efficiency advantages of distilled generation.

Motion customization comparison on fast distilled video models
Visual comparison of motion customization on fast distilled video models. Directly applying existing training-free methods to distilled models leads to severe degradation: object motion may not follow the reference and dynamic camera motion can corrupt both structure and background. MotionEcho transfers the reference motion while maintaining visual quality and text alignment under highly accelerated few-step inference.

Method Overview

Given a reference video, MotionEcho extracts motion priors to initialize the student model with a motion-preserving noisy latent. During inference, the teacher and student models perform motion customization using motion loss gradients, while the distilled student remains the efficient primary backbone. Teacher guidance is applied through prediction interpolation at sub-interval endpoints to correct the student's sampling trajectory. To preserve efficiency, an adaptive acceleration strategy selectively triggers teacher guidance and truncates teacher denoising iterations, allowing the student to generate the final video in a few steps with high motion fidelity.

Pipeline of MotionEcho

Qualitative Evaluation

The examples below compare motion customization on fast distilled video generators. Each group shows a reference video, the result produced by MotionEcho, and the result obtained by directly applying a training-free motion guidance baseline to the distilled student model. Across object motion, camera motion, and hybrid motion, direct guidance on the distilled trajectory often produces motion drift, temporal artifacts, or structural degradation. MotionEcho restores the student's sampling trajectory with selective teacher guidance, enabling the generated video to follow the reference motion while preserving visual quality and fast few-step inference.

Legend: green prompts denote MotionEcho; blue prompts denote the direct training-free guidance baseline on the distilled model.

Reference Video (Orbit Shot)

"A island, on the ocean, sunny day."

"A island, on the ocean, sunny day."

Reference Video

"A fox sitting in a snowy mountain."

"A fox sitting in a snowy mountain."

Reference Video (Pan Left)

"desert is captured with a pan left camera."

"desert is captured with a pan left camera."

Reference Video

"Monkeys play with coconuts."

"Monkeys play with coconuts."

Reference Video (Tilt Up)

"snowy filed is captured with a tilt up camera."

"snowy filed is captured with a tilt up camera."

Reference Video

"Snowflakes falling in the wind."

"Snowflakes falling in the wind."

Quantitative Evaluation

We evaluate MotionEcho on distilled UNet- and DiT-based video generators using text alignment, temporal consistency, motion fidelity, FID, and inference time. The results show that teacher-guided trajectory correction improves motion fidelity and visual quality while keeping the speed advantage of distilled generation. On TurboV2, MotionEcho remains effective from 16 steps down to 4 steps; on Video-Blade with Wan2.1 teacher guidance, it consistently improves motion preservation over training-free baselines while reducing inference cost. The user study below summarizes human preferences over text alignment, temporal consistency, motion fidelity, and appearance appeal.

Quantitative comparison of VideoCrafter2-based methods on TurboBench
Quantitative comparison of Wan2.1-1.3B-based methods on DavisBench
Ablation study of the key components in MotionEcho
Human evaluation results
User study results.

MotionEcho for TurboV2 16 steps, 8 steps, 4 steps


MotionEcho for AD-L 8 steps, 4 steps


MotionEcho on DiT-based Video Generators


BibTeX

        @inproceedings{rong2026when,
            title={When Distillation Breaks Motion Control: Restoring Generative Trajectories for Fast Video Generators},
            author={Rong, Jintao and Xie, Xin and Yu, Xinyi and Ou, Linlin and Zhang, Xinyu and Shen, Chunhua and Gong, Dong},
            booktitle={European Conference on Computer Vision},
            year={2026},
            url={https://euminds.github.io/motionecho/}
          }