Few-step autoregressive video generators enable streaming generation, yet they run every token through the final denoising step, regardless of how much refinement it needs. We find this uniform computation is often unnecessary: many tokens already closely match their eventual full-step outputs in the initial steps, while others require refinement until the end. We introduce Speculative Forcing, a framework that treats intermediate clean estimates as drafts and predicts when individual tokens can be safely accepted early. Once accepted, a token is frozen as its final output and undergoes no further denoising, while its cached keys and values remain available as context for the remaining tokens. We explore two alternative verifier designs: a training-free one based on similarity to clean content and stability across steps, and a learned one that reads the frozen generator's intermediate features to estimate each token's remaining gap to its full-step output. Across short-video, long-video, and world generation, Speculative Forcing preserves the quality of full-step sampling while substantially reducing computation. On LongLive, it matches the four-step generator with ~1.7 denoising steps per token, running over 1.5x faster at 41.7 and 37.8 fps. On Lingbot-World 2.0, where camera motion continually changes the visible content, it maintains quality with ~2.5 denoising steps per token and runs 1.35x faster at 24.5 fps.
Figures & tables
Figure 1: Compared with full-step sampling (a), Speculative Forcing treats intermediate token estimates as drafts, accepts those that have converged, and refines only the rest (b), achieving comparable quality with fewer denoising steps and higher throughput (c).
Figure 2: Token-wise convergence during denoising. We visualize latent differences between each chunk’s k -step prediction and the baseline four-step output. (a) In video generation, background and object regions that remain similar to history tend to converge early, while other regions continue to change. (b) In world generation, previously observed regions often converge early, whereas newly revealed regions tend to require further denoising.
Figure 3: Speculative Forcing. Baseline runs every token through the full denoising schedule. Speculative Forcing instead treats each token’s intermediate clean estimate as a draft and asks a verifier to predict its remaining gap relk(i) to the full-step output. Tokens predicted to have converged are accepted and committed, after which they enter the next step only as keys and values, so the following denoising pass is computed for the rejected tokens alone.
Method
Mean Steps ↓
Through. (FPS)
Evaluation scores ↑
Total
Quality
Semantic
LongLive ( Yang et al., 2025a )
1-step
1.00
67.97
79.06
80.03
75.17
2-step
2.00
44.54
82.46
83.06
80.09
3-step
3.00
33.15
83.08
83.45
81.58
4-step
4.00
26.40
83.08
83.49
81.43
Table 1: Comparison on 5s videos with LongLive. Mean Steps is the measured average number of denoising passes per token. Standard VBench 16-dimension protocol, throughput on a single H100.
Method
Mean Steps ↓
Through. (FPS)
Drift ↓
Total Score ↑
Quality Score ↑
Semantic Score ↑
VBench-Long dimension scores ↑
Subject Consistency
Background Consistency
Motion Smoothness
Dynamic Degree
Aesthetic Quality
Imaging Quality
LongLive ( Yang et al., 2025a )
1-step
1.00
61.6
2.930
80.82
81.87
76.64
96.94
95.76
98.24
49.63
60.09
63.81
2-step
2.00
40.9
1.992
82.32
82.99
79.61
97.67
96.38
98.60
44.81
62.92
67.66
3-step
3.00
30.6
1.738
82.60
83.09
80.67
98.09
96.75
98.77
38.98
63.71
68.69
4-step
4.00
24.5
1.722
82.69
83.29
80.30
98.22
96.99
98.85
39.17
64.43
68.52
Table 2: Comparison on 30s long videos with LongLive. Evaluated on VBench-Long.
Method
Mean Steps ↓
Through. (FPS)
RPE
Drift ↓
Quality Score ↑
VBench dimension scores ↑
Trans ↓
Rot ↓
Subject Consistency
Background Consistency
Motion Smoothness
Dynamic Degree
Aesthetic Quality
Imaging Quality
Lingbot-World 2.0 ( Gao et al., 2026 )
1-step
1.00
46.9
0.552
0.360
5.579
77.19
81.31
87.23
96.98
96.50
58.38
66.63
2-step
2.00
30.7
0.345
0.255
3.999
81.68
87.71
90.28
97.10
98.50
65.98
70.65
3-step
3.00
22.8
0.329
0.251
3.361
82.38
88.42
90.67
97.13
99.00
67.14
71.61
4-step
4.00
18.1
0.328
0.253
3.094
82.62
88.50
90.83
97.23
99.00
67.18
72.24
Table 3: World-model comparison on dynamic videos. Results with the autoregressive Lingbot-World 2.0 ( Gao et al., 2026 ) , evaluated on VBench. RPE is the relative pose error of the camera trajectory. Quality Score aggregates the six dimensions reported here.
Figure 4: Qualitative comparisons on video generation and world modeling. Both our head and training-free verifiers preserve visual quality comparable to the four-step baseline without visibly increasing quality drift over the illustrated rollouts on our benchmark.
Figure 5: Qualitative ablations of verification and commitment granularity. Our learned verifier handles distortions that challenge training-free verification. Premature chunk-wise acceptance propagates errors to later chunks, while motion-based verification struggles to distinguish camera-induced changes from distortions.
Table 9
Appendix figures & tables6 assets
Supplementary material from the paper’s appendix.
Appendix
Verifier signal
ϵ=0.16
ϵ=0.24
ϵ=0.32
k=1
k=2
k=3
k=1
k=2
k=3
k=1
k=2
k=3
Learned verifier (head) design
On-policy training
0.932
0.909
0.905
0.935
0.889
0.902
0.941
0.871
0.887
Per-token MLP
0.936
0.910
0.913
0.940
0.894
0.911
0.946
0.876
0.888
Ours H
0.933
0.911
0.910
0.934
0.890
0.906
0.944
0.871
0.887
Latent-based verification signals
Appendix
Table A: Verification accuracy on LongLive. We report AUROC ↑ for identifying tokens requiring further refinement, defined by relk(i)>ϵ .
Method
Mean Steps ↓
Through. (FPS)
Drift ↓
Quality Score ↑
Imaging Quality ↑
On-policy training
2.57
24.5
2.940
82.67
72.40
Per-token MLP
2.52
24.8
2.899
82.67
72.48
w/o spatiotemporal smoothing
2.55
24.7
2.882
82.58
72.54
Ours H
2.55
24.5
2.839
82.65
72.65
Appendix
Table B: Verifier ablations on Lingbot-World 2.0. Learned verifier variants are calibrated to our operating point ( ϵ=0.24 ).
Method
Mean Steps
Through. (FPS)
Total
Quality
Subject Consist.
Backgr. Consist.
Temporal Flicker
Motion Smooth.
Dynamic Degree
Aesthetic Quality
Imaging Quality
1-step
1.00
67.97
79.06
80.03
90.43
93.51
99.20
98.24
45.00
61.06
63.97
2-step
2.00
44.54
82.46
83.06
95.88
95.84
99.35
98.59
46.67
65.05
67.65
3-step
3.00
33.15
83.08
83.45
96.91
96.75
99.40
98.76
41.11
66.55
68.39
4-step
4.00
26.40
83.08
83.49
97.13
96.98
99.38
98.84
37.78
67.21
68.82
Surprise Forcing ( Shi et al., 2026 )
3.59
27.38
83.11
83.53
97.13
96.99
99.39
98.83
38.33
67.23
68.80
Ours TF (matched to ε=0.24 )
1.97
39.77
83.16
83.55
96.97
96.51
99.43
98.76
41.67
66.64
68.83
Appendix
Table C: Quality evaluation on LongLive. Evaluated on VBench.
Method
Mean Steps
Through. (FPS)
Total
Semantic
Object Class
Multiple Objects
Human Action
Colour
Spatial Relation
Scene
Appear. Style
Temporal Style
Overall Consist.
1-step
1.00
67.97
79.06
75.17
90.27
64.57
94.80
91.03
68.39
46.45
21.11
23.28
26.62
2-step
2.00
44.54
82.46
80.09
95.52
79.88
97.20
90.92
77.32
55.77
20.62
24.06
26.92
3-step
3.00
33.15
83.08
81.58
96.80
87.20
96.60
91.25
78.87
58.75
20.58
24.20
26.78
4-step
4.00
26.40
83.08
81.43
96.27
87.26
96.20
90.78
78.21
59.65
20.55
24.21
26.65
Surprise Forcing ( Shi et al., 2026 )
3.59
27.38
83.11
81.42
96.28
87.18
96.20
90.87
78.22
59.52
20.55
24.21
26.66
Ours TF (matched to ε=0.24 )
1.97
39.77
83.16
81.62
96.49
86.23
97.40
91.04
79.47
59.46
20.47
24.23
26.72
Appendix
Table D: Semantic evaluation on LongLive. Evaluated on VBench.
Method
Mean Steps
Through. (FPS)
Drift
Total
Quality
Subject Consist.
Backgr. Consist.
Temporal Flicker
Motion Smooth.
Dynamic Degree
Aesthetic Quality
Imaging Quality
1-step
1.00
61.59
2.930
80.82
81.87
96.94
95.76
99.24
98.24
49.63
60.09
63.81
2-step
2.00
40.91
1.992
82.32
82.99
97.67
96.38
99.27
98.60
44.81
62.92
67.66
3-step
3.00
30.62
1.738
82.60
83.09
98.09
96.75
99.31
98.77
38.98
63.71
68.69
4-step
4.00
24.45
1.722
82.69
83.29
98.22
96.99
99.28
98.85
39.17
64.43
68.52
Surprise Forcing ( Shi et al., 2026 )
3.22
27.61
1.674
82.89
83.52
98.19
97.04
99.35
98.80
41.57
64.80
68.44
Ours TF
1.71
38.78
1.685
82.75
83.28
98.11
96.77
99.44
98.74
41.57
63.83
68.27
Appendix
Table E: Quality evaluation on LongLive. Evaluated on VBench-Long.
Method
Mean Steps
Through. (FPS)
Drift
Total
Semantic
Object Class
Multiple Objects
Human Action
Colour
Spatial Relation
Scene
Appear. Style
Temporal Style
Overall Consist.
1-step
1.00
61.59
2.930
80.82
76.64
90.99
71.92
95.67
92.21
67.74
49.88
21.08
23.39
26.40
2-step
2.00
40.91
1.992
82.32
79.61
93.58
81.67
98.00
91.87
75.71
52.77
20.74
23.92
26.65
3-step
3.00
30.62
1.738
82.60
80.67
92.24
86.96
97.33
91.28
78.54
56.14
20.60
24.11
26.61
4-step
4.00
24.45
1.722
82.69
80.30
92.47
84.48
95.67
89.56
79.43
57.83
20.58
24.09
26.43
Surprise Forcing ( Shi et al., 2026 )
3.22
27.61
1.674
82.89
80.39
92.85
84.55
96.33
89.99
79.43
56.77
20.58
24.14
26.58
Ours TF
1.71
38.78
1.685
82.75
80.65
92.75
84.93
97.33
90.09
79.74
57.76
20.55
23.91
26.63
Appendix
Table F: Semantic evaluation on LongLive. Evaluated on VBench-Long.