Organizations: School of Artificial Intelligence, Beijing Normal University, Beijing, China · Institute of Artificial Intelligence and Future Networks, Beijing Normal University, Zhuhai, China · Shenzhen University of Advanced Technology, Shenzhen, China
Autoregressive (AR) video diffusion models enable long-form video generation but remain expensive due to repeated multi-step denoising. Existing training-free acceleration methods rely on binary cache-or-recompute decisions, overlooking intermediate cases where direct reuse is too coarse yet full recomputation is unnecessary. Moreover, asynchronous AR schedules assign different noise levels to co-generated frames, yet existing methods process the entire valid interval uniformly. To address these AR-specific inefficiencies, we present SCOPE, a training-free framework for efficient AR video diffusion. SCOPE introduces a tri-modal scheduler over cache, predict, and recompute, where prediction via noise-level Taylor extrapolation fills the gap between reuse and recomputation with explicit stability controls backed by error propagation analysis. It further introduces selective computation that restricts execution to the active frame interval. On MAGI-1 and SkyReels-V2, SCOPE achieves up to 4.73x speedup while maintaining quality comparable to the original output, outperforming all training-free baselines.
Figures & tables
Figure 1. SCOPE achieves large speedup while preserving near-original quality on both MAGI-1 and SkyReels-V2. A teaser figure showing SCOPE's speedup over the original pipeline on MAGI-1 and SkyReels-V2.
Figure 2. At Frame 13 over steps 54–59: (a) Taylor prediction tracks the ground-truth feature more closely than reuse-only; (b) Taylor prediction also yields lower feature error. Two plots for SkyReels-V2 540P generation. The curves denote cross-prompt means and the shaded bands denote cross-prompt standard deviations. The left plot compares the feature value norm of the ground-truth feature, a reuse-only approximation, and Taylor prediction at Frame 13 over denoising steps 54 to 59, with Taylor prediction staying closer to the ground truth. The right plot compares mean absolute feature errors for reuse-only and Taylor prediction, showing lower error for Taylor prediction.
Figure 3. Conceptual step-matrix view of asynchronous autoregressive denoising. At each iteration, only part of the valid frame interval is active; dark cells mark frames whose scheduling state is still advancing. An illustration of an asynchronous autoregressive denoising schedule, highlighting the active frame interval used by selective computation.
Figure 4. Overview of SCOPE for accelerating autoregressive video diffusion by reducing redundant computation in both the spatial and temporal dimensions through selective computation and predictive extrapolation. A framework figure for SCOPE. The left part shows autoregressive video generation across multiple chunks with denoising inside each chunk. The middle top shows a frame-by-step denoising matrix where different frames are at different stages. The middle bottom shows selective computation over the active frame interval. The right part shows predictive extrapolation along the temporal denoising trajectory using cached history.
Model
Method
Efficiency
Visual Quality
Time (s) ↓
Speedup ↑
FLOPs (P) ↓
Speedup ↑
VBench ↑
LPIPS ↓
SSIM ↑
PSNR ↑
SkyReels-V2 DF-1.3B
Original
1452.41
1.00 ×
245.01
1.00 ×
81.51%
0.0000
1.0000
∞
Δ -DiT
1223.01
1.19 ×
201.60
1.22 ×
74.57%
0.6052
0.5228
14.25
TeaCache-slow
697.60
2.08 ×
109.44
2.24 ×
79.83%
0.4436
0.5986
15.60
TeaCache-fast
559.76
2.59 ×
84.68
2.89 ×
77.49%
0.4786
0.5595
15.59
TaylorSeer-slow
941.41
1.54 ×
130.76
1.87 ×
75.54%
0.6838
0.4516
10.32
Table 1. Main comparison on SkyReels-V2 DF-1.3B and MAGI-1 4.5B-distill, with all results measured on a single NVIDIA A800 80GB GPU. LPIPS, SSIM, and PSNR are computed against the Original output as reference. Best and second-best accelerated results are shown in bold and underlined, respectively. Original is excluded from ranking.
Figure 5. Qualitative comparison of all methods on representative prompts from the two models. The left two groups show results on SkyReels-V2, while the right group shows results on MAGI-1. Each method row is annotated with its end-to-end speedup on SkyReels-V2 and MAGI-1, respectively. Compared with other accelerated baselines, SCOPE preserves object structure and visual fidelity more consistently while maintaining the strongest overall acceleration-quality tradeoff. Representative qualitative comparison across all methods on the two target models, with each row annotated by its speedup on SkyReels-V2 and MAGI-1.
Figure 6. Tri-modal decision timeline comparison between SkyReels-V2 (top) and MAGI-1 (bottom). Each row shows the Cache , Predict , and Recompute decisions across denoising iterations. Decision timeline visualization showing cache, predict, and recompute mode distributions across denoising iterations for both MAGI-1 and SkyReels-V2.
Config (τc,τp)
Efficiency
Quality
Time (s) ↓
Speedup ↑
LPIPS ↓
SSIM ↑
PSNR ↑
SkyReels-V2
(0.12,0.30)
353.11
4.11 ×
0.1723
0.7581
23.17
(0.15,0.36)
326.21
4.45 ×
0.1798
0.7460
22.74
(0.18,0.42)
307.34
4.73 ×
0.1900
0.7309
21.96
(0.21,0.48)
281.56
5.16 ×
0.2152
0.7018
20.69
Table 2. Sensitivity analysis across threshold settings on both models. Each configuration is denoted as (τc,τp) where τc is the cache threshold and τp is the prediction threshold.
Figure 7. Bounded skip-length sensitivity analysis visualized across runtime and quality metrics for SkyReels-V2 and MAGI-1. A single-column 2 by 2 figure for the bounded skip-length sensitivity analysis. The top-left panel shows Time, the top-right panel shows 1-LPIPS, the bottom-left panel shows SSIM, and the bottom-right panel shows PSNR for SkyReels-V2 and MAGI-1.
Figure 8. Denoising time of Original versus SCOPE at varying video lengths. Left: SkyReels-V2 DF-1.3B (97–737 frames). Right: MAGI-1 4.5B-distill (120–480 frames). Annotations indicate the speedup at each frame count. Two side-by-side bar charts comparing denoising time of Original and SCOPE across different frame counts, with speedup annotations above each pair.
Figure 9. Peak GPU memory comparison under short and long video generation. Left: SkyReels-V2 at 257 and 480 frames. Right: MAGI-1 at 240 and 480 frames. A single-column memory comparison figure with two panels. The left panel shows short-video and long-video peak GPU memory for six methods on SkyReels-V2 at 257 and 480 frames, and the right panel shows the same comparison on MAGI-1 at 240 and 480 frames.
Figure 12
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Method
Model
Key Parameter
Value
Δ -DiT
MAGI-1
cache_interval
8
SkyReels-V2
cache_interval
3
TeaCache-slow
MAGI-1
rel_l1_thresh
0.008
SkyReels-V2
teacache_thresh
0.10
TeaCache-fast
MAGI-1
rel_l1_thresh
0.015
SkyReels-V2
teacache_thresh
0.15
Appendix
Table 3. Baseline configurations on both target models.
Config
Efficiency
Quality
Time (s) ↓
Speedup ↑
LPIPS ↓
SSIM ↑
PSNR ↑
No selective
390.12
3.72 ×
0.1685
0.8053
24.42
M 0.55 / L 0.35
343.27
4.23 ×
0.2198
0.6878
21.42
M 1.00 / L 0.75
318.48
4.56 ×
0.1901
0.7302
22.03
M 1.00 / L 1.00
307.34
4.73 ×
0.1900
0.7309
21.96
Appendix
Table 4. Stage-ratio study for selective computation on SkyReels-V2.
Predictor
Efficiency
Quality
Time (s) ↓
Speedup ↑
LPIPS ↓
SSIM ↑
PSNR ↑
SkyReels-V2
auto
329.67
4.41 ×
0.1900
0.7313
21.97
momentum
306.70
4.74 ×
0.1898
0.7317
21.98
taylor1
306.41
4.74 ×
0.1902
0.7308
21.97
taylor2
307.34
4.73 ×
0.1900
0.7309
21.96
Appendix
Table 5. Predictor comparison across both target models.
Max Skip
Efficiency
Quality
Time (s) ↓
Speedup ↑
LPIPS ↓
SSIM ↑
PSNR ↑
SkyReels-V2
3
473.34
3.07 ×
0.1724
0.7586
23.14
4
377.42
3.85 ×
0.1803
0.7438
22.48
5
307.34
4.73 ×
0.1900
0.7309
21.96
6
268.76
5.40 ×
0.2087
0.7124
21.08
Appendix
Table 6. Effect of max_skip_steps on runtime and quality for SCOPE.
Figure 13. Visual comparison on Infinity under the quality-first setting. Zoom in for best viewing. Single-column qualitative comparison on Infinity between the Original baseline and SCOPE.
Method
Time ↓
Speedup ↑
CLIPScore ↑
ImageReward ↑
Original
3.2511
1.00 ×
0.3204
1.4110
SCOPE
2.0791
1.56 ×
0.3202
1.3133
Appendix
Table 7. Autoregressive image generation acceleration on Infinity with synchronized timing. Time is reported in seconds per image.
Figure 14. More Visual Comparisons on SkyReels-V2. Zoom in for best viewing. Additional qualitative comparison on SkyReels-V2 across all methods.
Figure 15. More Visual Comparisons on MAGI-1. Zoom in for best viewing. Additional qualitative comparison on MAGI-1 across all methods.
School of Computer Science and Technology, Hainan University · MAC Lab, Department of Artificial Intelligence, School of Informatics, Xiamen University · Zhejiang Normal University, Jinhua, China