PianoFlow: Music-Aware Streaming Piano Motion Generation with Bimanual Coordination
Organizations: Zhejiang University Hangzhou, Zhejiang, China · Renmin University of China Beijing, China · Beijing Forestry University Beijing, China · Chengdu Minto Tech Chengdu, Sichuan, China
Abstract
Audio-driven bimanual piano motion generation requires precise modeling of complex musical structures and dynamic cross-hand coordination. However, existing methods often rely on acoustic-only representations lacking symbolic priors, employ inflexible interaction mechanisms, and are limited to computationally expensive short-sequence generation. To address these limitations, we propose PianoFlow, a flow-matching framework for precise and coordinated bimanual piano motion synthesis. Our approach strategically leverages MIDI as a privileged modality during training, distilling these structured musical priors to achieve deep semantic understanding while maintaining audio-only inference. Furthermore, we introduce an asymmetric role-gated interaction module to explicitly capture dynamic cross-hand coordination through role-aware attention and temporal gating. To enable real-time streaming generation for arbitrarily long sequences, we design an autoregressive flow continuation scheme that ensures seamless cross-chunk temporal coherence. Extensive experiments on the PianoMotion10M dataset demonstrate that PianoFlow achieves superior quantitative and qualitative performance, while accelerating inference by over 9\times compared to previous methods.
Figures & tables
| Method | Venue | Left Hand | Right Hand | FID | RTF | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| FGD | WGD | PD | Smooth | FGD | WGD | PD | Smooth | ||||
| EmoTalk ( Peng et al., 2023 ) | ICCV 2023 | 0.445 | 0.232 | 0.044 | 0.353 | 0.360 | 0.259 | 0.033 | 0.313 | 4.645 | - |
| LivelySpeaker ( Zhi et al., 2023 ) | ICCV 2023 | 0.538 | 0.220 | 0.038 | 0.406 | 0.535 | 0.249 | 0.030 | 0.334 | 4.157 | - |
| PianoMotion ( Gan et al., 2024 ) | ICLR 2025 | 0.372 | 0.217 | 0.037 | 0.248 | 0.351 | 0.244 | 0.030 | 0.205 | 3.281 | 1.746 |
| S2C ( Liu et al., 2025c ) | MM 2025 | 0.309 | 0.215 | 0.035 | 0.229 | 0.293 | 0.242 | 0.028 | 0.198 | 3.012 | 5.723 |
| PianoFlow (Ours) | - | 0.266 | 0.210 | 0.029 | 0.200 | 0.263 | 0.238 | 0.027 | 0.184 | 2.674 | 0.186 |
| Method | Left Hand | Right Hand | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FGD | WGD | PD | Smooth | FDE | FGD | WGD | PD | Smooth | FDE | |
| PianoMotion ( Gan et al., 2024 ) + SWF | 0.432 | 0.220 | 0.045 | 0.253 | 0.334 | 0.424 | 0.250 | 0.037 | 0.208 | 0.269 |
| S2C ( Liu et al., 2025c ) + SWF | 0.443 | 0.223 | 0.041 | 0.251 | 0.350 | 0.397 | 0.252 | 0.035 | 0.206 | 0.320 |
| PianoFlow + SWF | 0.317 | 0.223 | 0.040 | 0.236 | 0.324 | 0.296 | 0.251 | 0.032 | 0.203 | 0.272 |
| PianoFlow + AFC | 0.309 | 0.222 | 0.040 | 0.232 | 0.312 | 0.290 | 0.249 | 0.032 | 0.199 | 0.255 |
| Method | Left Hand | Right Hand | FID | ||||||
|---|---|---|---|---|---|---|---|---|---|
| FGD | WGD | PD | Smooth | FGD | WGD | PD | Smooth | ||
| PianoFlow | 0.266 | 0.210 | 0.029 | 0.200 | 0.263 | 0.238 | 0.027 | 0.184 | 2.674 |
| w/ Hubert | 0.293 | 0.214 | 0.032 | 0.251 | 0.286 | 0.240 | 0.029 | 0.196 | 2.868 |
| w/o MIDI | 0.277 | 0.211 | 0.030 | 0.203 | 0.281 | 0.241 | 0.028 | 0.194 | 2.733 |
| w/o Decoupling | 0.283 | 0.211 | 0.038 | 0.221 | 0.293 | 0.241 | 0.035 | 0.198 | 2.877 |
| w/o Stage1 | 0.285 | 0.216 | 0.095 | 0.243 | 0.275 | 0.244 | 0.085 | 0.217 | 2.841 |
Human Motion Generation
Human motion generation creates articulated movement from language, audio, video, spatial constraints, or interaction goals.
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