Authors: Saijun Wang, Guanfeng Tang, Hongbo Zhao, Zhicheng Lei, Yutong Zhang, Wei Ye, Rui Fan
Organizations: College of Electronic and Information Engineering, Tongji University, Shanghai 201804, China · College of Electronic and Information Engineering, Shanghai Institute of Intelligent Science and Technology, State Key Laboratory of Autonomous Intelligent Unmanned Systems, Tongji University, Shanghai 201804, China
Audio-visual segmentation (AVS) aims to segment sounding objects at the pixel level by integrating auditory and visual cues. However, existing methods are predominantly developed under the monaural setting and primarily rely on cross-modal semantic correspondence, which limits their ability to distinguish visually similar instances of the same semantic class. In contrast, humans naturally exploit binaural hearing, where interaural differences and direction-dependent acoustic filtering introduced by the head and pinnae provide physically grounded spatial cues for accurate sound source localization. Motivated by this observation, we introduce binaural audio-visual instance segmentation (BiAVIS), a new task that leverages synchronized binaural audio and video frames to segment sounding instances. To advance research on this task, we establish two benchmarks by manually annotating an existing binaural audio-visual dataset and collecting a new real-world dataset, BiAVIS-Bench, in more challenging and diverse scenarios. The proposed BiAVIS model (BiAVISM) features an audio-only sound source localization network that directly projects binaural spatial cues onto the image plane to learn spatial and semantic priors for sounding instances. A query-level audio-visual fusion strategy is subsequently introduced to inject these informative priors into the instance segmentation decoder. Extensive experiments conducted on the two proposed benchmarks demonstrate the superior performance of the BiAVISM over previous monaural AVS methods, especially in resolving instance-level intra-class ambiguity. On the more challenging BiAVIS-Bench, BiAVISM achieves 26.65 mAP and 45.90 FSLA, corresponding to relative improvements of approximately 35.35% over AVISM in mean average precision (mAP) and 11.62% over ACVIS in frame-level sound localization accuracy (FSLA).
Figures & tables
Figure 1: Comparison between AVISM and the proposed BiAVISM. AVISM conditions queries with monaural audio, leading to intra-class instance ambiguity. In contrast, BiAVISM exploits spatial priors, enabling segmentation of the truly sounding instance.
Figure 2: Overview of the proposed BiAVIS framework. The Audio Encoder denotes the complete binaural feature extraction pipeline, consisting of two channel-specific spectrogram encoders followed by a binaural-difference encoder. The audio-only SSL branch predicts sounding probability and class probability maps, while the visual branch follows a Mask2Former-style segmentation decoder. Binaural priors are injected via query-level cross-attention, where object queries are conditioned with binaural features to form audio-aware queries for segmentation prediction. The model is trained with segmentation, class-wise localization, and audio-visual consistency losses.
Figure 3: Dataset collection setup and category statistics. (a) Our binaural audio-visual recording system, consisting of a ZED 2i binocular camera and a Mic.x Binaural I microphone mounted on a custom rig. (b) Instance counts per category in BiAVIS-Bench. (c) Instance counts per category in FAIR-Play.
Figure 4: Qualitative comparison of sounding-object segmentation results across diverse scenes.
Task
Networks
Audio
FAIR-Play
BiAVIS-Bench
mAP
FSLA
FSLAn
FSLAs
FSLAm
mAP
FSLA
FSLAn
FSLAs
FSLAm
VIS
Mask2Former [ 9 ] (CVPR’22)
✗
35.71
60.56
3.52
72.38
44.23
22.32
40.22
10.58
45.07
16.74
MP-Former [ 40 ] (CVPR’23)
✗
26.43
54.17
0.00
73.98
24.40
18.89
19.82
2.88
21.95
10.89
PolarNeXt [ 32 ] (CVPR’25)
✗
30.41
36.55
0.00
51.12
14.45
15.72
28.61
2.88
33.32
4.71
AVSS
COMBO [ 38 ] (CVPR’24)
✓
33.27
56.27
17.65
63.86
45.91
19.00
38.49
9.62
43.46
13.88
AVSegFormer [ 12 ] (AAAI’24)
✓
27.36
44.88
76.47
59.75
18.36
15.47
28.61
4.81
32.30
11.15
Table 1: Quantitative comparison of different models from related tasks on the FAIR-Play and BiAVIS-Bench test sets.
Gaussian
Lmse
Ljs
CC ↑
SIM ↑
EMD ↓
✗
✓
✗
0.01
0.02
5.35
✗
✓
✓
0.06
0.05
4.20
✓
✓
✗
0.31
0.24
3.41
✓
✓
✓
0.37
0.33
2.87
Table 2: Ablation study on the proposed localization loss conducted on the BiAVIS-Bench dataset.
Lc
Lavc
mAP ↑
FSLA ↑
FSLAn ↑
FSLAs ↑
FSLAm ↑
✗
✗
21.65
30.90
0.00
34.09
19.55
✗
✓
13.12
33.58
4.81
37.76
14.51
✓
✗
20.81
32.73
3.85
36.46
16.87
✓
✓
26.65
45.90
60.58
48.14
24.78
Table 3: Ablation study on the proposed class and audio-visual consistency loss conducted on the BiAVIS-Bench dataset.
Dataset
Audio
mAP ↑
FSLA ↑
FSLAn ↑
FSLAs ↑
FSLAm ↑
FAIR-Play
avg
35.14
54.90
88.24
63.29
39.01
L/L
33.80
54.96
84.71
63.53
39.02
R/R
37.27
55.21
87.06
64.46
38.02
L/R
37.63
62.90
89.41
68.63
51.85
BiAVIS-Bench
avg
22.95
43.07
32.69
47.74
13.92
L/L
21.59
42.43
33.65
47.81
17.84
Table 4: Ablation study on binaural versus monauralized audio inputs.
Dalian University of Technology Dalian, Liaoning, China · Carnegie Mellon University Pittsburgh, Pennsylvania, USA · Yale University New Haven, Connecticut, USA