We present TADP, a temporally adaptive differential privacy (DP) framework for inference-time privacy-preserving video generation under fixed-length clip-replacement adjacency. TADP uses a dual-branch design to extract identity and expression representations, clips and privatizes both branches with temporally adaptive Gaussian mechanisms whose noise scales depend only on preceding privatized releases within the same clip and are bounded below by history-uniform calibrated minima, and accounts for their joint release via adaptive Rényi Differential Privacy (RDP) composition. The clip-level RDP guarantee is converted to (ε,δ)-differential privacy, while soft quantization and subsequent temporal processing are applied only after privatization as DP post-processing. Experiments on facial expression datasets show reduced identity leakage under evaluated attacks, usable perceptual quality and temporal stability, and high facial expression recognition utility relative to the evaluated privacy-preserving baselines. TADP formally satisfies clip-level DP and empirically provides a favorable privacy--utility trade-off under the evaluated threat models and datasets.
Figures & tables
Figure 1: TADP jointly privatizes identity and expression representations over a fixed-length clip, providing a clip-level (ε,δ) -DP guarantee. All subsequent temporal modeling and decoding operate only on privatized representations.
Figure 2: Overview of the TADP framework. The pipeline contains three stages: Feature Extraction, Privacy Preservation, and Post-processing. A video is divided into fixed-length clips, and every frame is processed by an Identity Encoder and an FE Encoder to obtain identity and facial-expression (FE) representations, which are stacked into clip-level features. In Privacy Preservation, each branch is clipped and privatized by temporally adaptive Gaussian noise, and the identity and FE RDP losses are composed to obtain the reported clip-level RDP guarantee. In Post-processing, the privatized identity and FE representations are mapped by Soft Quantization with the ID Codebook and FE Codebook into soft-quantized codebook representation, followed by Fusion, Intra-clip temporal modeling, Inter-clip memory, Frame to clip aggregation, Clip to video assembly, and a Decoder that produces PP Clips and the final PP Video. All post-privatization operations use only privatized representations and public metadata, incurring no additional privacy loss.
Dataset
Parameter
Identity branch
Expression branch
Shared/clip-level
CREMA-D
Clipping percentile
95th
95th
–
Clipping norm
Cid=0.539
Cexpr=0.844
–
Calibration clipping rate
ridcal=0.05
rexprcal=0.05
–
Test clipping rate
ridtest=0.0659
rexprtest=0.1617
–
Sensitivity bound
2Cid=1.078
2Cexpr=1.688
–
Target-loss allocation
ρid=0.4
ρexpr=0.6
ρid+ρexpr=1
Table 1: Complete dataset- and branch-specific privacy-accounting configuration.
Dataset
Length statistic
K
α⋆
εvideo
CREMA-D
Minimum
1
8
3.981
Near mean (mean =4.37 )
4
4
8.510
Maximum
10
3
14.517
RAVDESS
Minimum
4
4
6.524
Near mean (mean =5.19 )
5
4
7.196
Maximum
7
4
8.539
Table 2: Dataset source-video clip-count statistics and conservative privacy guarantees obtained by composing non-overlapping 16-frame clip releases. “Near mean” is the integer clip count nearest to the dataset mean.
Method
Full-video R3D FER Acc. ↑
Full-video TimeSformer FER Acc. ↑
Full-video VideoMAE V2 FER Acc. ↑
Frame-level PLR ↓
16-frame cPLR ↓
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
FER-only
87.043
88.675
92.683
93.032
90.860
91.944
N/A
N/A
N/A
N/A
SPAct [ 9 ]
70.963
72.548
73.576
74.815
73.978
74.722
32.573
35.921
40.322
41.111
Controlled [ 44 ]
77.955
79.551
80.153
80.958
81.021
81.944
2.088
4.983
2.220
5.833
Swapping [ 46 ]
65.194
65.918
68.985
69.112
70.054
71.111
4.023
4.856
4.194
5.556
MinusFace [ 28 ]
76.562
78.618
82.586
82.956
83.871
83.611
6.569
8.874
6.935
9.166
Table 3: Full-video FER under K -specific composed budgets, frame-level PLR, and 16-frame cPLR (%); see Sec. 4.1.3 .
Dataset
Method
FWE ↓
FVD ↓
tLPIPS ↓
T-ID ↑
CREMA-D
SPAct [ 9 ]
0.1023
309.5686
0.0974
0.1032
Controlled [ 44 ]
0.1285
485.5864
0.1459
0.0481
Swapping [ 46 ]
0.0345
295.5713
0.0348
0.7691
MinusFace [ 28 ]
0.0586
395.5390
0.1586
0.0287
K.P. [ 45 ]
0.0923
408.3363
0.1028
0.1785
Pi-Net [ 7 ]
0.0358
292.4851
0.0557
0.7802
Table 4: Temporal consistency on CREMA-D and RAVDESS.
Figure 3: Video temporal consistency visualization. The 64 generated frames are arranged in temporal order from left to right and top to bottom, showing that the privacy-preserved video maintains smooth frame-to-frame appearance and expression dynamics.
Method
CREMA-D
RAVDESS
SSIM ↓
PSNR ↓
PLR ↓
cPLR ↓
SSIM ↓
PSNR ↓
PLR ↓
cPLR ↓
U-Net
SPAct [ 9 ]
0.5358
23.1459
42.890%
54.913%
0.5421
23.0751
43.861%
56.497%
Controlled [ 44 ]
0.4283
11.8560
5.847%
10.573%
0.4641
11.9177
6.600%
11.556%
Swapping [ 46 ]
0.5012
17.9647
38.950%
42.321%
0.5186
18.0398
39.315%
44.789%
MinusFace [ 28 ]
0.4591
13.5457
97.395%
98.667%
0.4461
13.5287
97.477%
98.991%
K.P. [ 45 ]
0.3959
11.8308
6.103%
9.425%
0.4512
10.314
6.813%
10.543%
Table 5: After U-Net and RVRT recovery attacks, evaluating on four metrics.
Method
Probe
CREMA-D
RAVDESS
TAR@FAR= 10−2↓
TAR@FAR= 10−3↓
EER ↑
DIR@FAR= 10−2↓
DIR@FAR= 10−3↓
TAR@FAR= 10−2↓
TAR@FAR= 10−3↓
EER ↑
DIR@FAR= 10−2↓
DIR@FAR= 10−3↓
Original
Direct
94.263
88.136
3.950
90.359±1.105
82.490±1.542
96.058
91.227
2.836
93.512±0.913
87.126±1.362
SPAct
Direct
38.670
22.448
28.743
31.592±2.431
16.884±1.920
41.869
25.797
26.540
34.644±3.153
19.725±2.539
Recovered
52.720
34.981
22.114
45.231±2.701
28.164±2.277
57.430
39.607
19.875
49.336±3.017
32.516±2.740
Controlled
Direct
6.405
2.127
42.810
4.953±0.830
1.573±0.418
8.213
2.877
40.622
6.549±1.193
2.094±0.650
Recovered
12.871
5.310
37.615
10.628±1.373
3.913±0.704
15.113
6.425
35.217
12.716±1.644
4.819±0.983
Table 6: Open-set identity verification and identification under anonymization-aware attackers. For each anonymization method, the identity attacker is separately adapted using only privacy-preserved outputs from the development actors. All evaluation actors are unseen during attacker adaptation. “Direct” denotes privacy-preserved probes, and “Recovered” denotes probes reconstructed by the method-specific RVRT attacker. Lower TAR and DIR and higher EER indicate stronger identity privacy.
Dataset
FID
MMD
O vs P
O vs R
P vs R
O vs P
O vs R
P vs R
U-Net
CREMA-D
130.5908
144.9318
72.0473
0.0308
0.0374
0.0014
RAVDESS
412.3707
436.4749
356.8630
0.0331
0.0427
0.0057
RVRT
CREMA-D
133.6474
164.9867
81.7367
0.0325
0.0395
0.0021
RAVDESS
454.1176
439.0419
350.8485
0.0510
0.0428
0.0052
Table 7: Comparison of identity feature distributions among original data (O), privacy-preserved data (P) and recovery-attacked data (R) under U-Net and RVRT.
Figure 4: t-SNE visualization of identity features on CREMA-D (left) and RAVDESS (right). Blue, orange, and green points denote original, privacy-preserved, and recovery-attacked identity features (U-Net), respectively.
Figure 5: t-SNE visualization of identity features on CREMA-D (left) and RAVDESS (right). Blue, orange, and green points denote original, privacy-preserved, and recovery-attacked identity features (RVRT), respectively.
Stage
Evaluated representation
Evaluator
CREMA-D (%)
RAVDESS (%)
Random chance
–
–
16.67
12.50
Pre-privatization
Clipped expression feature zˉexpr
Linear probe
62.03±0.15%
68.05±0.45%
DP release
Privatized expression feature z~expr
Linear probe
20.04±0.11%
19.54±0.34%
Post-processing
Soft-quantized expression feature zqexpr
Linear probe
58.80±0.06%
64.17±0.68%
Post-processing
Temporally modeled feature hˉ
Linear probe
61.52±0.09%
67.04±0.57%
Released video
Generated video X^
R3D
83.871
82.278
Table 8: Stage-wise expression information. TADP is frozen and FER is evaluated using temporal mean pooling followed by one linear layer. The released videos are evaluated using R3D, TimeSformer and VideoMAE V2 trained on the corresponding anonymized training videos. Results are mean ± std over three seeds 42, 43, and 44. The video-level R3D, TimeSformer and VideoMAE V2 entries are single-run results reproduced from the primary evaluation and are shown only as downstream-utility references; they are not directly comparable to the latent-probe accuracies. The pre-privatization representation is included as a non-private latent reference and is never released.
Dataset
Intervention
R3D FER ↑
TimeSformer FER ↑
VideoMAE V2 FER ↑
PLR ↓
cPLR ↓
CREMA-D
Full TADP
83.871
87.634
88.011
1.237
1.452
Expression branch shuffled
31.223
34.742
35.486
1.181
1.405
Identity branch shuffled
80.620
84.945
85.328
1.051
1.219
Both branches shuffled
18.407
19.118
18.831
0.989
1.104
Expression branch set to zero
25.713
28.986
29.652
1.298
1.423
Noise-only input
17.220
17.876
17.556
1.089
1.085
Table 9: Inference-time input-intervention analysis. All interventions are applied to the same trained TADP model. Shuffling is performed across clips, preserving the approximate marginal distribution of each representation while breaking its correspondence with the submitted clip.
Dataset
R3D FER
TimeSformer FER
VideoMAE V2 FER
Prediction agreement
CREMA-D
83.76±0.31
87.51±0.28
87.92±0.24
94.13±0.97
RAVDESS
82.15±0.44
88.94±0.36
88.62±0.31
92.67±0.86
Table 10: Utility stability over independent Gaussian releases of the same test clips. FER is measured after regenerating the complete test set for each release seed.
Dataset
Branch
Mechanism
smin
Observed Min
Observed Mean
Std
Observed Max
CREMA-D
ID
A6 static
8.921
8.921
8.921
0
8.921
CREMA-D
ID
TADP adaptive
8.921
8.921
9.275
0.1623
14.348
CREMA-D
Expression
A6 static
11.406
11.406
11.406
0
11.406
CREMA-D
Expression
TADP adaptive
11.406
11.406
11.891
0.1939
13.024
RAVDESS
ID
A6 static
17.088
17.088
17.088
0
17.088
RAVDESS
ID
TADP adaptive
17.088
17.088
17.667
0.2450
25.107
Table 11: Realized adaptive-scale statistics over all non-padded frames in the actor-disjoint test sets.
Dataset
Branch
Clipped-feature norm
Perturbation norm
Noise/signal ratio
∥zˉib∥2
∥sb,iξb,i∥2
∥zˉib∥2∥sb,iξb,i∥2
CREMA-D
ID
0.269±0.093
296.7±8.4
1166.6[669.9,2031.4]
CREMA-D
Expression
0.422±0.039
380.4±10.5
904.9[772.4,1060.2]
RAVDESS
ID
0.341±0.104
565.2±14.8
1732.3[1058.6,2834.5]
RAVDESS
Expression
0.460±0.052
500.1±13.3
1093.7[904.1,1323.2]
Table 12: Clipped-feature and Gaussian-perturbation magnitudes over all non-padded frames in the actor-disjoint test sets. Both quantities are measured before the fixed global rescaling, and their noise-to-signal ratio is invariant to this rescaling. We report mean ± standard deviation for the norms and median with 5th-95th percentiles for the per-frame ratio.
Dataset
Branch
Codebook norm
Assignment entropy
Max probability
Cross-draw agreement
CREMA-D
ID
0.98±0.07
1.84±0.31
0.43±0.09
0.06
CREMA-D
Expression
1.04±0.09
2.11±0.28
0.37±0.08
0.09
RAVDESS
ID
1.01±0.08
1.76±0.34
0.46±0.10
0.05
RAVDESS
Expression
1.06±0.10
2.04±0.30
0.39±0.08
0.08
Table 13: Soft-quantization diagnostics over non-padded test frames. Assignment entropy is computed using natural logarithms; with 1,000 codebook entries, uniform assignment has entropy log(1000)=6.91 . Cross-draw agreement is the proportion of independent releases selecting the same top-1 codebook entry for the same frame.
Input / setting
WAR ↑
UAR ↑
Expression clipping rate ↓
tLPIPS ↓
Original DFEW videos
55.708
45.115
–
–
TADP reconstruction without DP perturbation
34.822
27.644
48.735
0.156
TADP with clip-level DP
20.912
16.839
48.761
0.211
Table 14: Cross-domain stress test on the in-the-wild DFEW dataset. Original-video performance provides a task-specific reference, while reconstruction without DP perturbation separates reconstruction and domain-shift errors from the additional degradation caused by privatization.
Variant
DP?
ρid,ρexpr
R3D: FER Acc. (%) ↑
TimeSformer: FER Acc. (%) ↑
VideoMAE V2: FER Acc. (%) ↑
PLR (%) ↓
cPLR (%) ↓
FWE ↓
FVD ↓
tLPIPS ↓
T-ID ↑
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
A1
No
–
84.221
83.181
88.436
89.686
89.652
90.273
3.387
5.556
3.899
6.592
0.0245
0.0211
290.3011
251.5844
0.0138
0.0258
0.7803
0.7923
A2
Yes
0.5, 0.5
53.954
42.591
52.582
52.513
54.637
58.397
2.043
4.444
2.933
5.231
0.1056
0.0987
302.1953
275.1840
0.0992
0.1304
0.5309
0.5812
A3
Yes
same as full
24.839
25.000
27.956
26.944
26.370
26.113
1.505
4.166
2.018
4.658
0.6743
0.7941
702.5868
689.4917
0.8702
0.8910
0.0859
0.0764
A4
Yes
same as full
62.957
65.833
62.903
64.722
67.370
68.104
1.290
4.722
2.548
4.801
0.0485
0.0397
327.0942
309.8031
0.0853
0.0944
0.5428
0.6041
A5
Yes
same as full
73.226
72.778
80.108
79.722
82.138
81.643
1.559
5.000
2.354
4.737
0.0281
0.0285
287.2386
261.5593
0.0258
0.0312
0.7903
0.7544
Table 15: Ablation study results for the dual-branch mechanism.
T
(R3D) FER Acc. ↑
PLR ↓
Time ↓
Memory ↓
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
CREMA-D
RAVDESS
8
84.301%
83.056%
1.290%
4.722%
21’32
4’57
58GB
62GB
16
83.871%
82.278%
1.237%
3.889%
21’45
4’59
66GB
73GB
32
53.011%
55.278%
1.129%
4.167%
22’14
5’08
78GB
85GB
Table 16: Ablation of the clip length at the same final clip-level privacy budget. Runtime and memory are measured on a single NVIDIA H100 GPU with a batch size of 2 on the test datasets.
Target ε
Achieved ε
ρid,ρexpr
sid,min,sexpr,min
FER Acc. ↑
PLR ↓
cPLR ↓
FWE ↓
FVD ↓
tLPIPS ↓
T-ID ↑
1
0.994
0.1, 0.9
69.124, 36.080
22.634%
1.129%
1.453%
0.2491
467.8613
0.6089
0.2548
2
1.985
0.2, 0.8
24.716, 19.351
25.161%
1.183%
1.937%
0.1986
368.6407
0.1201
0.4164
4
3.981
0.4, 0.6
8.921, 11.406
83.871%
1.237%
1.452%
0.0214
284.8561
0.0317
0.7937
8
7.954
0.5, 0.5
4.251, 6.656
53.954%
2.043%
2.025%
0.1056
302.1953
0.0992
0.5309
Table 17: Privacy–utility trade-off under jointly accounted dual-branch clip-level privacy budgets on CREMA-D.
Target ε
Achieved ε
ρid,ρexpr
sid,min,sexpr,min
FER Acc. ↑
PLR ↓
cPLR ↓
FWE ↓
FVD ↓
tLPIPS ↓
T-ID ↑
1
0.991
0.1, 0.9
87.160, 39.466
25.556%
4.167%
4.491%
0.6104
385.6503
0.8045
0.2108
2
1.983
0.3, 0.7
25.406, 22.593
28.333%
4.444%
4.821%
0.0511
329.0132
0.1458
0.5311
3
2.988
0.3, 0.7
17.088, 15.197
82.278%
3.889%
4.444%
0.0203
249.5107
0.0414
0.8032
8
7.962
0.5, 0.5
5.342, 7.256
43.889%
5.000%
6.333%
0.0704
333.6845
0.0961
0.6853
Table 18: Privacy–utility trade-off under jointly accounted dual-branch clip-level privacy budgets on RAVDESS.
Facial expression recognition relies on facial data that inherently expose identity and thus raise significant privacy concerns. Current privacy-preserving methods typically fail in realistic open-set video settings where identities are unknown, and identity labels are unavailable. We propose a two-stage framework for video-based privacy-preserving FER in challenging open-set settings that requires no identity labels at any stage. To decouple privacy and utility, we first train an identity-suppression network using intra- and inter-video knowledge priors derived from real-world videos without identity labels. This network anonymizes identity while preserving expressive cues. A subsequent denoising module restores expression-related information and helps recover FER performance. Furthermore, we introduce a falsification-based validation method that uses recognition priors to rigorously evaluate privacy robustness without requiring annotated identity labels. Experiments on three video datasets demonstrate that our method effectively protects privacy while maintaining FER accuracy comparable to identity-supervised baselines.
Feng Xu, Xun Li, Lars Petersson +3
School of CSE, UNSW Sydney, Australia · CSIRO’s Data61, Australia
Recent diffusion-based video generation models have enabled high-quality personalized video customization through both tuning-based pipelines, which fine-tune a video diffusion model, and reference-based pipelines such as image-to-video generation. However, these capabilities raise serious concerns about personal privacy, identity ownership and intellectual property protection. Existing anti-customization works focus on protecting images, while protection for videos against both reference- and tuning-based customization remains largely underexplored. Protecting videos in this setting raises three challenges: (i) Image-level perturbations, optimized frame by frame, cannot survive temporal compression by 3D video VAE. (ii) A video-level perturbation optimized on a single video is vulnerable to temporal editing and fails to protect unseen videos. (iii) Temporally inconsistent perturbations are not robust to temporal attacks. To address these challenges, we propose Temporally Consistent Universal Adversarial Perturbations (TC-UAP), the first protection method against both reference- and tuning-based video customization. TC-UAP optimizes an identity-level multi-frame UAP over sliding windows from multiple videos, accounting for local temporal dependencies induced by temporal compression in video VAE and enabling a single perturbation to protect unseen videos of varying lengths. Moreover, we introduce intrinsic temporal modeling and an extrinsic surrogate temporal-attack loss, which make the perturbation temporally consistent and robust to unseen temporal attacks. Empirically, quantitative and qualitative results show that TC-UAP achieves the strongest identity protection compared with existing methods under both reference- and tuning-based video customization, and remains robust under multiple unseen temporal attacks.
Yuxin Huang, Ziming Hong, Mingming Gong +3
1Sydney AI Centre, The University of Sydney · University of Melbourne · 5Mohamed bin Zayed University of Artificial Intelligence +2
Test-time adaptation (TTA) can reduce error on new and different data by updating the model on these inputs during inference. However, these updates raise the issue of privacy w.r.t. the testing data, because the model parameters now depend on all past inputs. To control this privacy risk, we cast multiple popular TTA methods (Tent, EATA, SAR, DeYO, and COME) into differential privacy (DP) forms that apply per-sample gradient clipping and Gaussian noise for all updates. On ImageNet-C, our DP-TTA methods provide adequate privacy at small cost to accuracy, and in the low-privacy regime the clipping mechanism of DP can even improve the accuracy and stability of adaptation in the continual setting. These improvements to privacy and accuracy come at only modest computational overhead. These first results on private TTA raise awareness of the issue, inform the development of more private test-time updates, and identify per-sample clipping as an effective technique for improving the accuracy and stability of adaptation.