Despite progress in speech-to-video synthesis, existing methods often struggle to capture cross-individual dependencies and provide fine-grained control over reactive behaviors in dyadic settings. To address these challenges, we propose InterDyad, a framework that enables naturalistic interactive dynamics synthesis via querying structural motion guidance. Specifically, we first design an Interactivity Injector that achieves video reenactment based on identity-agnostic motion priors extracted from reference videos. Building upon this, we introduce a MetaQuery-based modality alignment mechanism to bridge the gap between conversational audio and these motion priors. By leveraging a Multimodal Large Language Model (MLLM), our framework is able to distill linguistic intent from audio to dictate the precise timing and appropriateness of reactions. To further improve lip-sync quality under extreme head poses, we propose Role-aware Dyadic Gaussian Guidance (RoDG) for enhanced lip-synchronization and spatial consistency. Finally, we introduce a dedicated evaluation suite with novelly designed metrics to quantify dyadic interaction. Comprehensive experiments demonstrate that InterDyad significantly outperforms state-of-the-art methods in producing natural and contextually grounded two-person interactions. Please refer to our project page for demo videos: https://interdyad.github.io/.
Figures & tables
Figure 2: Overview of our InterDyad framework. Top : The overall architecture is constructed by sequentially stacking Transformer blocks and trained via denoising to synthesize dyadic conversational videos with synchronized audio-visual human dynamics and coherent inter-subject interactions. Bottom : We illustrate the interactivity injection mechanism, which leverages switchable multimodal inputs to enable rich and controllable synthesis of interactive motion patterns.
Figure 2
Method
Visual & Identity
Synchronization
Interactivity (Ours)
FID ↓
FVD ↓
ID-Cons ↑
Sync-C ↑
Sync-D ↓
DI-Sync ↑
DI-Sali ↑
MultiTalk [ 24 ]
49.6047
477.6189
0.5275
3.2253
5.8941
0.2333
0.8889
InfiniteTalk [ 52 ]
46.3762
440.6732
0.6418
3.0446
5.5412
0.2371
0.8560
LongCat-VA [ 39 ]
45.4698
548.8332
0.6059
3.1985
5.7200
0.2417
1.1145
Ours
38.3260
415.5064
0.6310
3.3067
4.1786
0.2747
1.2349
Table 1: Quantitative comparison on our curated dyadic conversational dataset. LongCat-VA denotes LongCat-Video-Avatar. “ ↑ ” indicates higher is better, and “ ↓ ” indicates lower is better. Best results are bolded , and the second best are underlined .
Figure 5: Qualitative comparison with existing baselines. The figure illustrates the generated inter-subject dynamics from different methods, where the numbers in red dots indicate three different timestep. Accumulated motion heatmaps are provided in the bottom row to visualize reaction intensity.
Configuration
Interactivity (Ours)
DI-Sync ↑
DI-Sali ↑
w/o Interactivity Injection
0.2041
0.7500
w/o MLLM Modality Alignment
0.2220
0.7800
Ours
0.2747
1.2349
Table 2: Ablation study on the core architectural designs. Best results are bolded .
Figure 6: Effect of RoDG on large-angle profile views. Compared to the baseline without RoDG, our full method ensures robust and accurate lip reconstruction for the active speaker under severe perspective shifts.
Symbol
Description
Value/Standard
τs
Minimum threshold for camera stability
3.66
τv
Maximum threshold for camera motion/flow
6.0
Cˉ
Mean clarity score of a video sequence
-
τc
Minimum threshold for visual clarity
0.95
Rbody
Frame ratio requirement for dual body detection
80%
Rface
Frame ratio requirement for dual face detection
30%
Table 3: Summary of Notations and Thresholds for Dataset Curation.
Figure 7: Qualitative results of our method on the single-person dataset. Each row represents a distinct conversation case, while columns show selected frames at different time steps to illustrate temporal progression. Our model consistently generates high-fidelity facial details and natural head motions that are precisely synchronized with the input audio across various subjects and expressive states.
Method
Visual & Identity
Synchronization
FID ↓
FVD ↓
ID-Cons ↑
Sync-C ↑
Sync-D ↓
MultiTalk [ 24 ]
34.3847
345.4332
0.6811
8.5122
2.1538
InfiniteTalk [ 52 ]
33.1035
329.2524
0.8260
8.5060
1.7574
LongCat-VA [ 39 ]
49.1042
491.3213
0.7332
7.7535
1.5684
Wan-S2V [ 11 ]
57.8167
585.7959
0.7093
7.3267
6.0978
Ours
33.0428
340.4103
0.7916
8.5386
1.4962
Table 4: Quantitative comparison on our single-person dataset. LongCat-VA denotes LongCat-Video-Avatar. “ ↑ ” indicates higher is better, and “ ↓ ” indicates lower is better. Best results are bolded , and the second best are underlined .
Dyadic conversational motion generation is essential for realistic interactive digital humans. Existing approaches typically model conversational behaviors within unified dyadic generators. However, such holistic formulations tend to couple self-speech-driven motion with partner-responsive social feedback, leaving the interaction-specific component implicit and underutilizing the speech-motion correspondence already learned by pretrained monologic motion models. We propose Learn2Chat, a unified framework that models dyadic motion as interaction modulation over pretrained monologic motion priors. This design separates intrinsic speech-driven motion from social interaction effects and enables more structured interaction modeling. Specifically, we introduce a Monologic-Anchored Motion Factorization scheme that leverages the semantic motion manifold learned from monologic data to disentangle audio-driven motion dynamics from interaction-induced modulation, yielding clean interaction representations from dyadic sequences. On top of this representation space, a Cross-Attentive Interaction Latent Prediction module maps paired speech signals to interaction latents through cross-branch attention and interaction alignment. During inference, the predicted interaction latents modulate canonical monologic motion to generate coherent and synchronized dyadic behaviors in a data-efficient manner. Extensive experiments on the DualTalk benchmark demonstrate that Learn2Chat achieves state-of-the-art performance across both quantitative metrics and perceptual evaluations. Moreover, the framework is model-agnostic and seamlessly integrates with diverse pretrained monologic motion backbones, highlighting the effectiveness of prior reuse and interaction adaptation for scalable conversational motion generation. More visual results are available on the project page.
Zikai Huang, Siyue Chen, Xuemiao Xu +4
School of Computer Science and Engineering, South China University of Technology, Guangdong, China · School of Design, South China University of Technology, Guangdong, China · Guangdong Engineering Center for Large Model and GenAI Technology +2
Large-scale dyadic interactive audio-visual dialogue (DIAD) datasets provide fundamental data resources for developing humanoid interactive virtual agents and digital humans. However, collecting such data is time-consuming, expensive, and ethically sensitive. To address this, we propose CHAT, a new dyadic interactive audio-visual dialogue generation (DIADG) framework that generates diverse, paired, and mutually responsive speech-face dialogue clips from a single textual prompt. CHAT unifies large language models and talking face models with interactive audio and facial behaviour refinement modules, enabling the generation of aligned dyadic dialogue clips with diverse contents and facial identities. Experiments show that CHAT outperforms existing related methods designed for similar tasks under both objective and subjective evaluations. Moreover, our synthesised CHAT-AVD-50k dataset serves as effective pre-training data for downstream interactive head generation, consistently improving PerFRDiff and ReactDiff on REACT 2024. CHAT offers a scalable alternative to the costly and ethically sensitive collection of real dyadic interaction data.
Junhao Song, Lluis Guasch, Xilin He +8
Department of Computing, Imperial College London, UK · Department of Earth Science & Engineering, Imperial College London, UK · Mohamed bin Zayed University of Artificial Intelligence, UAE +8
Co-speech gesture generation in dyadic conversations for creating immersive virtual avatars remains highly challenging. Existing models often struggle to balance kinematic stability with rhythmic responsiveness and suffer from semantic entanglement, leading to either generic mean-pose regression or unnatural micro-jitters. To address these challenges, we propose SynerGest, a high-fidelity dyadic gesture generation framework grounded in Contrastive Flow Matching (CFM). Specifically, our CFM objective explicitly penalizes mismatched semantic pairs during training, discouraging spatial shortcuts and over-smoothed predictions while improving conditional semantic alignment. Furthermore, to overcome architectural bottlenecks, we introduce the Impulse-Trend Synergistic Attention (ITSA) module. Grounded in the key insight of decoupling "what moves" from "when it moves," ITSA models sharp, speech-driven rhythmic impulses separately from continuous kinematic trends, supporting precise audio-motion synchronization and global structural stability. Extensive qualitative and quantitative evaluations on two public datasets demonstrate that SynerGest achieves state-of-the-art performance, delivering contextually responsive and kinematically fluid dyadic interactions.
Chengxiang Guo, Jian Wang, Lanmiao Liu +3
Faculty of Information Engineering and Automation Kunming University of Science and Technology Kunming, China · Yunnan Key Laboratory of Artificial Intelligence · Utrecht University Utrecht, Netherlands +2