AV-NeRF: Learning Neural Fields for Real-World Audio-Visual Scene Synthesis
Susan LiangChao HuangYapeng TianAnurag KumarChenliang Xu
Presents a multimodal Neural Radiance Field framework that synthesizes synchronized novel-view video frames and binaural spatial audio along arbitrary camera trajectories by integrating sound propagation physics and 3D visual geometry.
Immersive virtual experiences in augmented and virtual reality require synchronized, realistic visuals and spatial audio. While recent advancements in neural radiance fields allow machines to render realistic visual viewpoints from novel positions, existing systems struggle to generate corresponding spatial sound in real-world settings. Previous acoustic synthesis approaches relied on synthetic impulse responses, discrete positions, or ground-truth imagery, limiting their ability to produce continuous, realistic audio-visual environments along arbitrary paths.
The article demonstrates AV-NeRF, a neural field framework designed to synthesize both video frames and matching binaural audio along arbitrary, novel camera trajectories in real-world environments. The system evaluates whether neural representations can integrate spatial acoustics with visual cues to generate consistent, multi-view audio-visual scenes directly from raw recordings.
The approach integrates visual scene rendering with an acoustic generation branch informed by environmental physics. The framework uses a visual neural field to capture 3D geometry and surface appearance, passing rendered depth and color features through an audio-visual mapping module to inform acoustic predictions. A specialized coordinate transformation calculates the listener's head orientation relative to the sound source rather than using absolute coordinates. To train and evaluate the framework, the authors assembled a real-world dataset comprising 3.8 hours of synchronized video and binaural audio recorded across indoor and outdoor environments, supplemented by experiments on a synthetic acoustic benchmark.
Evaluation shows that the proposed approach consistently outperforms existing methods across diverse environments. On the real-world dataset, the system achieved a 34% to 39% relative improvement in time-frequency magnitude accuracy and an 8% to 11.6% improvement in time-domain envelope accuracy compared to prior neural acoustic representations. Ablation experiments confirmed that both the audio-visual feature mapping and relative direction encoding were essential to performance, with their removal significantly degrading generation quality. On the synthetic benchmark, the framework delivered a 21% improvement in reverberation decay estimation over previous state-of-the-art baselines. Additional testing showed that the model successfully extended to complex environments with multiple sound sources.
These findings demonstrate that machines can generate coherent, high-fidelity multimodal environments directly from standard recordings without requiring expensive, specialized acoustic simulation pipelines. This capability lowers the cost and complexity of developing immersive simulations, digital twins, and virtual reality content. However, the system requires careful data capture, as performance degrades in environments with heavy ambient background noise or visually uniform surfaces that lack clear geometric features. Additionally, the framework does not explicitly model complex reverberation effects, and models must be trained separately for each individual scene.
Decision-makers investing in multimodal media pipelines should consider adopting neural field frameworks that jointly model visual geometry and spatial acoustics. Before deploying these models commercially, engineering teams should conduct pilot implementations to develop noise-filtering pipelines and test cross-scene generalization to avoid retraining from scratch for every new space. Future development must also establish ethical guidelines and watermarking protocols to mitigate the risk of creating deceptive synthetic media.
- Paper: NeRF: Representing Scenes as Neural Radiance Fields for View Synthesis, Ben Mildenhall et al. (2020). This foundational paper introduces Neural Radiance Fields (NeRF) for novel view synthesis, providing the underlying visual representation and volumetric rendering principles that AV-NeRF integrates with acoustic propagation.
- Paper: NeRF in the Wild: Neural Radiance Fields for Unconstrained Photo Collections, Ricardo Martin-Brualla et al. (2021). This work establishes techniques for adapting neural radiance fields to complex real-world captures, directly informing how real-world video datasets are synthesized in multimodal settings.
- Paper: A Closer Look at Weakly-Supervised Audio-Visual Source Localization, Shentong Mo et al. (2022). This paper investigates weakly-supervised visual sound source localization, establishing essential concepts for grounding acoustic signals to visual coordinates in unconstrained scenes.
- Paper: Seeing and Hearing: Open-domain Visual-Audio Generation with Diffusion Latent Aligners, Yazhou Xing et al. (2024). This work extends multimodal audio-visual generation into open-domain diffusion models, building upon joint audiovisual synthesis paradigms to handle broader, unconstrained scene creation.
- Paper: Conditional Generation of Audio from Video via Foley Analogies, Yuexi Du et al. (2023). This paper explores conditional video-to-audio synthesis using Foley analogies, presenting a complementary generative framework for matching acoustic textures to visual materials.
- Paper: Egocentric Audio-Visual Object Localization, Chao Huang et al. (2023). This study applies spatial audio-visual modeling to egocentric perspectives with camera motion, extending coordinate alignment principles to wearable dynamic scenarios.
