ThinkOmni

A Reasoning-Driven Omni-Modal LLM Framework for Audio Forgery Detection and Localization

Accepted to ACM MM 2026

Shenzhen University  ·  Afirstsoft Technology Group Co., Ltd.

* Corresponding author

PaperarXiv Repository ModelsSoon FACoTSoon

From implicit prediction

Evidence-driven analysis

Existing audio forgery detection and localization methods often overfit dataset-specific low-level artifacts, limiting their generalization to subtle, localized, and unseen manipulations.

ThinkOmni jointly performs explicit forensic reasoning, spoofing detection, and temporal manipulation localization. It connects semantic inconsistencies, acoustic artifacts, and spectral-visual evidence with the detection and localization targets instead of relying only on implicit latent correlations.

Comparison of existing SSL- and ALLM-based methods with ThinkOmni
Can audio forgery detection and localization benefit from explicit forensic reasoning beyond implicit low-level features?
01

Reason

Generate explicit forensic reasoning from semantic, acoustic, and spectral-visual evidence.

02

Detect

Classify audio as fully real, fully fake, or partially fake.

03

Localize

Predict one or more temporal intervals corresponding to manipulated segments.

Forensic-Aware Chain-of-Thought

FACoT

A 100K-sample dataset with structured forensic evidence and reasoning annotations for explicit reasoning supervision.

FACoT dataset construction pipeline
FACoT construction: eight public source datasets, seed CoT annotation, expert verification, SFT-based expansion, and CLAP-based audio-text consistency filtering.

100Kaudio samples

Structured forensic evidence and reasoning annotations.

8source datasets

19LA, HAD, PS, LAV-DF, ArEnAV, LPS, SINE, and AV-1M++.

3authenticity classes

Fully real, fully fake, and partially fake.

Method

Forensic-Aware Modality-Incremental Learning (FMIL)

Built on Qwen2.5-Omni, ThinkOmni progressively integrates semantic, acoustic, and spectral-visual representations while reducing interference among heterogeneous modalities.

ThinkOmni framework and forensic-aware modality-incremental learning
01

Semantic Forensic Adaptation (SFA)

Establish transferable semantic reasoning from speech content and speaker information.

02

Acoustic Forensic Augmentation (AFA)

Introduce fine-grained acoustic evidence to capture subtle manipulation artifacts.

03

Multi-modal Forensic Refinement (MFR)

Integrate spectrogram-based visual cues for cross-modal verification.

Semantic-Acoustic Forensic Enhancer (SAFE)

Local and global forensic modeling

SAFE comprises a local cross-attention branch for fine-grained cue interaction and a global forgery discriminator for long-range forensic modeling. A learned gate fuses both views before the Thinker backbone.

Architecture of the SAFE module

Evaluation

Detection and localization across data distributions

ThinkOmni is evaluated on the eight FACoT source datasets and two held-out cross-dataset benchmarks under the protocol reported in the paper.

Cross-dataset evaluation

Cross-dataset temporal localization

ADD 2023 Track 2 and Speech-Forensics are held out from training. ThinkOmni achieves 74.67% average mAP, exceeding the best SSL-based method by 43.73 points and the best ALLM-based method by 15.32 points.

mAP is averaged over temporal IoU thresholds from 0.5 to 0.95. Claims are limited to the two held-out benchmarks evaluated in the paper.

Cross-dataset ablation of reasoning supervision and inference strategies
Under direct inference, FCML improves mAP by 10.43%. ShuffCoT degrades all metrics, confirming the importance of sample-specific rationales.

Qualitative analysis

Inspect the reasoning

Browse all 84 samples from 10 datasets. Each entry preserves the complete ThinkOmni response from its source TXT file without editing or truncation.

Loading all samples...

Citation

Use ThinkOmni in your research

The paper is available on arXiv and has been accepted to ACM MM 2026.

@misc{xu2026thinkomni,
  title  = {ThinkOmni: A Reasoning-Driven Omni-Modal LLM Framework for Audio Forgery Detection and Localization},
  author = {Yuxiong Xu and Kaiqing Lin and Bin Li and Haodong Li and Sheng Li},
  year   = {2026},
  eprint = {2607.26553},
  archivePrefix = {arXiv}
}