# MOSS-Audio

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MOSS-Audio is an open-source **audio understanding model** from [MOSI.AI](https://mosi.cn/#hero), the [OpenMOSS team](https://www.open-moss.com/), and [Shanghai Innovation Institute](https://www.sii.edu.cn/). It performs unified modeling over complex real-world audio, supporting **speech understanding, environmental sound understanding, music understanding, audio captioning, time-aware QA, and complex reasoning**. In this release, we provide **four models**: **MOSS-Audio-4B-Instruct**, **MOSS-Audio-4B-Thinking**, **MOSS-Audio-8B-Instruct**, and **MOSS-Audio-8B-Thinking**. The Instruct variants are optimized for direct instruction following, while the Thinking variants provide stronger chain-of-thought reasoning capabilities. ## News * 2026.6.1: We have released the [MOSS-Audio Technical Report](https://arxiv.org/pdf/2606.01802) on arXiv. * 2026.4.20: We have added the MOSS-Audio fine-tuning code and documentation. See `finetune/FINETUNE.md` for LoRA and full-parameter training examples. * 2026.4.13: 🎉🎉🎉 We have released [MOSS-Audio](https://huggingface.co/collections/OpenMOSS-Team/moss-audio). Blog coming soon! ## Contents - [Introduction](#introduction) - [Model Architecture](#model-architecture) - [DeepStack Cross-Layer Feature Injection](#deepstack-cross-layer-feature-injection) - [Time-Aware Representation](#time-aware-representation) - [Released Models](#released-models) - [Evaluation](#evaluation) - [Quickstart](#quickstart) - [Environment Setup](#environment-setup) - [Basic Usage](#basic-usage) - [Fine-tuning](#fine-tuning) - [Gradio App](#gradio-app) - [SGLang Serving](#sglang-serving) - [More Information](#more-information) - [Citation](#citation) ## Introduction

Understanding audio requires more than simply transcribing words — it demands the ability to perceive acoustic cues, recognize speakers and emotions, interpret environmental sounds, reason over temporal context, and handle complex multi-step inference. **MOSS-Audio** is built to unify these capabilities within a single model. - **Speech & Content Understanding**: Accurately recognizes and transcribes spoken content from audio inputs, producing clean and well-structured text outputs. Supports both word-level and sentence-level timestamp alignment. - **Speaker, Emotion & Event Analysis**: Identifies speaker characteristics, analyzes emotional states based on tone, timbre, and context, and detects key acoustic events within the audio. - **Scene & Sound Cue Extraction**: Extracts meaningful cues from background sounds, environmental noise, music, and non-speech signals to infer scene context and atmosphere. - **Music Understanding**: Analyzes musical style, emotional progression, instrumentation, and salient acoustic features in music segments. - **Audio Question Answering & Summarization**: Answers questions and generates summaries about speech, podcasts, meetings, interviews, and environmental recordings, helping users efficiently extract key information. - **Time-Aware QA**: Supports time-aware questions, including word-level and sentence-level timestamp ASR. - **Complex Reasoning**: Performs multi-hop reasoning over audio content, powered by chain-of-thought training and reinforcement learning. ## Model Architecture

MOSS-Audio follows a modular design comprising three components: an audio encoder, a modality adapter, and a large language model. Raw audio is first encoded by **MOSS-Audio-Encoder** into continuous temporal representations at **12.5 Hz**, which are then projected into the language model's embedding space through the adapter and finally consumed by the LLM for auto-regressive text generation. Rather than relying on off-the-shelf audio frontends, we train a dedicated encoder from scratch to obtain more robust speech representations, tighter temporal alignment, and better extensibility across acoustic domains. ### DeepStack Cross-Layer Feature Injection Using only the encoder's top-layer features tends to lose low-level prosody, transient events, and local time-frequency structure. To address this, we design a **DeepStack**-inspired cross-layer injection module between the encoder and the language model: in addition to the encoder's final-layer output, features from earlier and intermediate layers are selected, independently projected, and injected into the language model's early layers, preserving multi-granularity information from low-level acoustic details to high-level semantic abstractions. This design is especially well-suited for audio understanding tasks, as it helps retain rhythm, timbre, transients, and background structure — information that a single high-level representation cannot fully capture. ### Time-Aware Representation Time is a critical dimension in audio understanding. To enhance explicit temporal awareness, we adopt a **time-marker insertion** strategy during pretraining: explicit time tokens are inserted between audio frame representations at fixed time intervals to indicate temporal positions. This design enables the model to learn "what happened when" within a unified text generation framework, naturally supporting timestamp ASR, event localization, time-based QA, and long-audio retrospection. ## Released Models | Model | Audio Encoder | LLM Backbone | Total Size | Hugging Face | ModelScope | |---|---|---|---:|---|---| | **MOSS-Audio-4B-Instruct** | MOSS-Audio-Encoder | Qwen3-4B | ~4.6B | [![Hugging Face](https://img.shields.io/badge/Huggingface-Model-orange?logo=huggingface)](https://huggingface.co/OpenMOSS-Team/MOSS-Audio-4B-Instruct) | [![ModelScope](https://img.shields.io/badge/ModelScope-Model-624AFF)](https://modelscope.cn/models/openmoss/MOSS-Audio-4B-Instruct) | | **MOSS-Audio-4B-Thinking** | MOSS-Audio-Encoder | Qwen3-4B | ~4.6B | [![Hugging Face](https://img.shields.io/badge/Huggingface-Model-orange?logo=huggingface)](https://huggingface.co/OpenMOSS-Team/MOSS-Audio-4B-Thinking) | [![ModelScope](https://img.shields.io/badge/ModelScope-Model-624AFF)](https://modelscope.cn/models/openmoss/MOSS-Audio-4B-Thinking) | | **MOSS-Audio-8B-Instruct** | MOSS-Audio-Encoder | Qwen3-8B | ~8.6B | [![Hugging Face](https://img.shields.io/badge/Huggingface-Model-orange?logo=huggingface)](https://huggingface.co/OpenMOSS-Team/MOSS-Audio-8B-Instruct) | [![ModelScope](https://img.shields.io/badge/ModelScope-Model-624AFF)](https://modelscope.cn/models/openmoss/MOSS-Audio-8B-Instruct) | | **MOSS-Audio-8B-Thinking** | MOSS-Audio-Encoder | Qwen3-8B | ~8.6B | [![Hugging Face](https://img.shields.io/badge/Huggingface-Model-orange?logo=huggingface)](https://huggingface.co/OpenMOSS-Team/MOSS-Audio-8B-Thinking) | [![ModelScope](https://img.shields.io/badge/ModelScope-Model-624AFF)](https://modelscope.cn/models/openmoss/MOSS-Audio-8B-Thinking) | > More model families, sizes, and variants will be released in the future. Stay tuned! ## Evaluation We evaluate MOSS-Audio on a comprehensive set of audio understanding benchmarks. Key results: - **General Audio Understanding**: MOSS-Audio-8B-Thinking achieves an average accuracy of **71.08**, with **77.33** on MMAU, **64.92** on MMAU-Pro, **66.53** on MMAR, and **75.52** on MMSU, outperforming all open-source models. - **Speech Captioning**: MOSS-Audio-Instruct variants lead across **11 out of 13** fine-grained speech description dimensions, with **MOSS-Audio-8B-Instruct** achieving the best overall average score (**3.7252**). - **ASR**: On a diverse ASR benchmark suite spanning 12 evaluation dimensions, MOSS-Audio achieves the **lowest overall CER (11.30)**, with particular strength in health-condition, code-switching, dialect, singing, and non-speech scenarios. - **Timestamp ASR**: MOSS-Audio-8B-Instruct achieves **35.77 AAS** on AISHELL-1 and **131.61 AAS** on LibriSpeech, dramatically outperforming Qwen3-Omni (833.66) and Gemini-3.1-Pro (708.24) in timestamp asr accuracy. ### General Audio Understanding (Accuracy↑)

Model Model Size MMAU MMAU-Pro MMAR MMSU Avg
Open Source (small)
Kimi-Audio7B72.4156.5860.8254.7461.14
Qwen2.5-Omni7B65.6052.2056.7061.3258.96
Audio Flamingo 37B61.2351.7057.9660.0457.73
Audio Flamingo Next8B76.1056.3451.0157.2060.16
MiMo-Audio-7B7B74.9053.3561.7061.9462.97
MiniCPM-o-4.59B70.9739.6555.7560.9656.83
MOSS-Audio-4B-Instruct4B75.7958.1662.5459.6864.04
MOSS-Audio-4B-Thinking4B77.6460.7563.9171.2068.37
MOSS-Audio-8B-Instruct8B77.0357.4864.4266.3666.32
MOSS-Audio-8B-Thinking8B77.3364.9266.5375.5271.08
Open Source (large)
Qwen3-Omni-30B-A3B-Instruct30B75.0061.2266.4069.0067.91
Step-Audio-R1.133B72.1860.8068.7564.1866.48
Step-Audio-R133B78.6759.6869.1575.1870.67
Closed Source
GPT4o-Audio-65.6652.3059.7858.7659.13
Gemini-3-Pro-80.1568.2881.7381.2877.86
Gemini-3.1-Pro-81.1073.4783.7081.3079.89
### Speech Captioning (LLM-as-a-Judge Score↑)

Speech Captioning (click to expand) | Model | gender | age | accent | pitch | volume | speed | texture | clarity | fluency | emotion | tone | personality | summary | Avg | |---|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:| | Audio-Flamingo-Next | 4.617 | 3.461 | 3.160 | 2.679 | 2.391 | 2.818 | 1.941 | 2.839 | 2.788 | 2.056 | 2.025 | 1.940 | 2.157 | 2.6825 | | Qwen3-Omni-30B-A3B-Instruct | 4.436 | 3.936 | 4.356 | 3.590 | 3.682 | 3.614 | 3.093 | 3.521 | 3.531 | **3.328** | 3.224 | 3.292 | 3.179 | 3.5986 | | Qwen3-Omni-30B-A3B-Thinking | 4.419 | 4.026 | 4.327 | 3.610 | 3.577 | 3.610 | 3.179 | 3.403 | 3.526 | 3.232 | 3.154 | 3.197 | 3.107 | 3.5667 | | Gemini-3-Pro | 4.191 | 3.835 | 4.181 | 3.392 | 3.254 | 3.320 | 2.998 | 3.347 | 3.524 | 3.055 | 2.997 | 3.023 | 2.775 | 3.3763 | | Gemini-3.1-Pro | 4.347 | **4.030** | 4.310 | 3.474 | 3.580 | **3.687** | 3.134 | 3.559 | 3.720 | 3.231 | 3.245 | 3.158 | 3.028 | 3.5772 | | MOSS-Audio-4B-Instruct | **4.697** | 3.980 | 4.497 | 3.628 | **3.722** | 3.564 | **3.407** | 3.841 | 3.744 | 3.311 | **3.282** | **3.305** | 3.259 | 3.7105 | | MOSS-Audio-8B-Instruct | 4.683 | 3.979 | **4.572** | **3.682** | 3.709 | 3.638 | 3.403 | **3.869** | **3.747** | 3.314 | 3.253 | 3.272 | **3.307** | **3.7252** |
### ASR | Model | Overall | Health Condition | Dialect | Singing | Non-Speech Vocalizations | Code-Switching | Acoustic Environment (Clean) | Acoustic Environment (Noisy) | Acoustic Characteristics: Whisper | Acoustic Characteristics: Far-Field / Near-Field | Multi-Speaker | Age | Semantic Content | |---|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:|---:| | Paraformer-Large | 15.77 | 22.18 | 43.45 | 32.34 | 4.95 | 12.65 | 3.11 | 4.67 | 5.02 | 17.46 | 20.33 | 14.96 | 7.14 | | GLM-ASR-Nano | 17.29 | 24.49 | 22.39 | 51.95 | 4.65 | 11.88 | 3.68 | 5.02 | 4.94 | 27.51 | 28.02 | 17.19 | 7.32 | | Fun-ASR-Nano | 12.04 | 21.99 | **7.80** | 19.35 | 4.76 | 11.23 | 2.98 | 3.46 | 3.78 | 18.38 | 19.82 | 14.95 | 6.08 | | SenseVoice-Small | 14.50 | 24.04 | 8.89 | 23.79 | 4.92 | 13.90 | 4.13 | 4.93 | 5.57 | 26.66 | 24.06 | 17.63 | 7.55 | | Kimi-Audio-7B-Instruct | 14.12 | 21.11 | 29.34 | 21.76 | 4.68 | 16.38 | **2.20** | **2.15** | 2.66 | 21.02 | 20.61 | 16.74 | 6.12 | | Audio-Flamingo-Next | 30.19 | 36.13 | 25.85 | 25.80 | 8.25 | 34.53 | 8.64 | 38.85 | 12.84 | 42.90 | 62.13 | 38.30 | 30.18 | | Qwen2.5-Omni-3B | 15.26 | 24.65 | 33.87 | 24.24 | 5.54 | 11.66 | 2.76 | 3.56 | 4.32 | 22.15 | 22.91 | 15.17 | 7.24 | | Qwen2.5-Omni-7B | 15.05 | 23.85 | 31.91 | 22.69 | 4.56 | 12.97 | 2.52 | 3.16 | 3.64 | 25.38 | 21.01 | 16.13 | 6.78 | | Qwen3-Omni-30B-A3B-Instruct | 11.39 | 20.73 | 15.63 | 16.01 | 4.73 | 11.30 | 2.23 | 2.47 | **1.90** | **17.08** | **18.15** | **11.46** | **5.74** | | **MOSS-Audio-4B-Instruct** | 11.58 | 21.11 | 11.84 | 10.79 | **4.01** | **10.11** | 3.11 | 3.72 | 3.29 | 18.48 | 20.33 | 15.09 | 8.15 | | **MOSS-Audio-8B-Instruct** | **11.30** | **19.18** | 8.76 | **9.81** | 4.31 | 10.18 | 2.70 | 3.20 | 2.75 | 24.04 | 24.36 | 15.26 | 7.69 |
Detailed ASR Results (click to expand)
Model Acoustic Environment (Clean) Acoustic Environment (Noisy) Acoustic Characteristics: Whisper Acoustic Characteristics: Far-Field / Near-Field Multi-Speaker Age Health Condition Semantic Content Code-Switching Dialect Singing Non-Speech Vocalizations
AISHELL-1
test
AISHELL-2
Android | IOS | Mic
THCHS-30
test
MAGICDATA-READ
test
AISHELL6-Whisper
normal | whisper
AliMeeting
Test_Ali_far | Test_Ali_near
AISHELL-4
test
SeniorTalk
sentence
ChildMandarin
test
AISHELL-6A
mild | moderate | severe | StutteringSpeech
AISHELL_6B
LRDWWS | Uncontrol
WenetSpeech
test-meeting
Fleurs
cmn_hans_cn
CS-Dialogue
test
TALCS
test
ASCEND
test
KeSpeech
test
WSYue-ASR-eval
short
MIR-1K
test
openc-pop
test
MNV_17
Paraformer-Large 1.98 3.28 | 3.21 | 3.00 4.07 4.67 1.11 | 8.92 25.64 | 9.27 20.33 17.31 12.60 6.98 | 9.30 | 13.34 | 10.74 47.59 | 45.08 7.88 6.40 10.64 10.77 16.55 11.48 75.42 57.70 6.98 4.95
GLM-ASR-Nano 2.89 3.75 | 3.73 | 3.78 4.23 5.02 0.83 | 9.06 40.27 | 14.76 28.02 20.33 14.06 8.74 | 12.11 | 14.38 | 12.29 50.34 | 49.09 9.70 4.94 11.06 11.07 13.50 9.72 35.07 95.87 8.03 4.65
Fun-ASR-Nano 2.16 3.04 | 2.99 | 3.07 3.65 3.46 0.81 | 6.76 27.21 | 9.55 19.82 16.96 12.94 6.60 | 8.81 | 12.98 | 10.30 47.42 | 45.84 7.39 4.76 10.47 8.09 15.13 7.43 8.17 35.85 2.84 4.76
SenseVoice-Small 3.23 4.16 | 4.02 | 3.96 5.26 4.93 1.25 | 9.88 37.01 | 16.31 24.06 21.07 14.18 7.62 | 9.85 | 14.39 | 11.47 52.92 | 47.97 8.35 6.75 12.81 10.52 18.38 10.45 7.34 39.51 8.07 4.92
Kimi-Audio-7B-Instruct 0.79 2.91 | 3.03 | 2.88 1.39 2.15 0.69 | 4.63 28.22 | 13.82 20.61 19.70 13.79 7.00 | 9.34 | 12.56 | 10.75 44.44 | 42.57 7.15 5.10 14.56 12.74 21.83 5.51 53.17 38.35 5.17 4.68
Audio Flamingo Next 6.85 7.22 | 8.12 | 8.62 12.41 6.24 6.48 | 19.20 60.68 | 25.12 62.13 39.44 23.06 24.13 | 29.40 | 35.69 | 21.90 56.17 | 49.52 54.46 12.86 30.52 40.42 32.63 16.97 34.74 40.06 11.54 8.25
Qwen2.5-Omni-3B 1.51 3.10 | 2.94 | 2.93 3.32 3.56 0.82 | 7.82 32.14 | 12.16 22.91 17.38 12.96 6.87 | 10.55 | 14.57 | 11.33 54.54 | 50.03 9.04 5.45 10.78 10.94 13.25 7.67 60.06 45.00 3.47 5.54
Qwen2.5-Omni-7B 1.16 2.88 | 2.77 | 2.73 3.06 3.16 0.71 | 6.57 32.03 | 18.73 21.01 19.96 12.29 7.27 | 10.94 | 12.92 | 10.53 51.99 | 49.45 8.43 5.13 14.02 10.46 14.42 6.40 57.43 42.62 2.75 4.56
Qwen3-Omni-30B-A3B-Instruct 0.95 2.70 | 2.72 | 2.57 2.21 2.47 0.59 | 3.22 25.72 | 8.44 18.15 14.13 8.79 6.20 | 8.88 | 11.59 | 10.25 45.80 | 41.65 6.64 4.84 12.94 8.33 12.64 5.87 25.39 30.81 1.21 4.73
MOSS-Audio-4B-Instruct 2.26 3.22 | 3.20 | 3.33 3.53 3.72 0.73 | 5.86 27.27 | 9.68 20.33 16.93 13.25 6.36 | 9.77 | 12.68 | 10.28 43.35 | 44.25 8.17 8.13 9.14 8.37 12.83 14.65 9.04 18.47 3.10 4.01
MOSS-Audio-8B-Instruct 1.82 2.97 | 2.95 | 2.91 2.82 3.20 0.69 | 4.80 36.82 | 11.25 24.36 17.42 13.10 5.84 | 8.94 | 11.52 | 9.72 39.76 | 39.27 7.86 7.52 9.07 8.22 13.26 9.18 8.33 17.24 2.39 4.31
### Timestamp ASR (AAS↓) | Model | AISHELL-1(zh) | LibriSpeech(en) | |---|---:|---:| | Audio-Flamingo-Next | -- | 211.15 | | Qwen3-Omni-30B-A3B-Instruct | 833.66 | 646.95 | | Gemini-3.1-Pro| 708.24 | 871.19 | | MOSS-Audio-4B-Instruct | 76.96 | 358.13 | | **MOSS-Audio-8B-Instruct** | **35.77** | **131.61** | ## Quickstart ### Environment Setup We recommend Python 3.12 with a clean Conda environment. The commands below are enough for local inference. #### Recommended setup ```bash git clone https://github.com/OpenMOSS/MOSS-Audio.git cd MOSS-Audio conda create -n moss-audio python=3.12 -y conda activate moss-audio conda install -c conda-forge "ffmpeg=7" -y pip install --extra-index-url https://download.pytorch.org/whl/cu128 -e ".[torch-runtime]" ``` #### Optional: FlashAttention 2 If your GPU supports FlashAttention 2, you can replace the last install command with: ```bash pip install --extra-index-url https://download.pytorch.org/whl/cu128 -e ".[torch-runtime,flash-attn]" ``` ### Basic Usage Download the model first: ```bash hf download OpenMOSS-Team/MOSS-Audio-4B-Instruct --local-dir ./weights/MOSS-Audio-4B-Instruct hf download OpenMOSS-Team/MOSS-Audio-4B-Thinking --local-dir ./weights/MOSS-Audio-4B-Thinking hf download OpenMOSS-Team/MOSS-Audio-8B-Instruct --local-dir ./weights/MOSS-Audio-8B-Instruct hf download OpenMOSS-Team/MOSS-Audio-8B-Thinking --local-dir ./weights/MOSS-Audio-8B-Thinking ``` Then edit `MODEL_PATH` / `AUDIO_PATH` in `infer.py` as needed, and run: ```bash python infer.py ``` The default prompt in `infer.py` is `Describe this audio.` You can directly edit that line if you want to try transcription, audio QA, or speech captioning. ### Fine-tuning We now provide an official fine-tuning script in `finetune/finetune.py`, with full instructions in `finetune/FINETUNE.md`. Install the extra dependencies needed for training: ```bash pip install librosa peft ``` Minimal example for LoRA fine-tuning: ```bash accelerate launch finetune/finetune.py \ --model_dir ./weights/MOSS-Audio-4B-Instruct \ --data_path train.jsonl \ --output_dir ./output/lora \ --use_lora \ --bf16 ``` The training data should be a JSONL file containing audio-text conversations. For data format, supported arguments, multi-GPU examples, and full-parameter fine-tuning, see `finetune/FINETUNE.md`. ### Gradio App Start the Gradio demo with: ```bash python app.py ``` ### SGLang Serving If you want to serve MOSS-Audio with SGLang, see the full guide in `moss_audio_usage_guide.md`. The shortest setup is: ```bash git clone -b moss-audio https://github.com/OpenMOSS/sglang.git cd sglang pip install -e "python[all]" pip install nvidia-cudnn-cu12==9.16.0.29 cd .. sglang serve --model-path ./weights/MOSS-Audio --trust-remote-code ``` If you use the default `torch==2.9.1+cu128` runtime, installing `nvidia-cudnn-cu12==9.16.0.29` is recommended before starting `sglang serve`. ## More Information - **MOSI.AI**: [https://mosi.cn](https://mosi.cn) - **OpenMOSS**: [https://www.open-moss.com](https://www.open-moss.com) ## LICENSE Models in MOSS-Audio are licensed under the Apache License 2.0. ## Citation ```bibtex @misc{yang2026mossaudiotechnicalreport, title={MOSS-Audio Technical Report}, author={Chen Yang and Chufan Yu and Hanfu Chen and Jie Zhu and Jingqi Chen and Ke Chen and Wenxuan Wang and Yang Wang and Yaozhou Jiang and Yi Jiang and Zhengyuan Lin and Ziqi Chen and Zhaoye Fei and Chenghao Liu and Jun Zhan and Kang Yu and Kexin Huang and Mingshu Chen and Qinyuan Cheng and Ruixiao Li and Shimin Li and Songlin Wang and Yang Gao and Yiyang Zhang and Xipeng Qiu}, year={2026}, eprint={2606.01802}, archivePrefix={arXiv}, primaryClass={cs.SD}, url={https://arxiv.org/abs/2606.01802}, } ``` ## Star History [![Star History Chart](https://api.star-history.com/svg?repos=OpenMOSS/MOSS-Audio&type=date&legend=top-left)](https://www.star-history.com/#OpenMOSS/MOSS-Audio&type=date&legend=top-left)