vllm-omni/examples/online_serving/moss_tts_nano

MOSS-TTS-Nano

Model

Model	Description
OpenMOSS-Team/MOSS-TTS-Nano	0.1B AR LM + MOSS-Audio-Tokenizer-Nano codec, 48 kHz stereo, ZH/EN/JA

Gradio Demo

An interactive Gradio demo is available with multilingual voice presets, custom voice cloning, and streaming support.

# Option 1: Launch server + Gradio together
./run_gradio_demo.sh

# Option 2: If server is already running
python gradio_demo.py --api-base http://localhost:8091

Then open http://localhost:7860 in your browser.

Features:

• 15 built-in voice presets (6 ZH · 4 EN · 5 JA)
• Custom voice cloning from uploaded reference audio
• Streaming mode (progressive PCM playback)

Launch the Server

vllm serve OpenMOSS-Team/MOSS-TTS-Nano --omni --port 8091

The deploy config at vllm_omni/deploy/moss_tts_nano.yaml auto-loads; no --stage-configs-path, --trust-remote-code, or --enforce-eager flags are needed.

Or use the convenience script:

./run_server.sh

Send TTS Request

Using curl

# Built-in voice preset
curl -X POST http://localhost:8091/v1/audio/speech \
    -H "Content-Type: application/json" \
    -d '{
        "input": "你好，这是语音合成测试。",
        "voice": "Junhao",
        "response_format": "wav"
    }' --output output.wav

# English preset
curl -X POST http://localhost:8091/v1/audio/speech \
    -H "Content-Type: application/json" \
    -d '{
        "input": "Hello, this is MOSS-TTS-Nano.",
        "voice": "Ava",
        "response_format": "wav"
    }' --output output_en.wav

Custom Voice Cloning

Provide a reference audio (base64 data URL) and its transcript:

REF_AUDIO=$(base64 -w 0 /path/to/reference.wav)
curl -X POST http://localhost:8091/v1/audio/speech \
    -H "Content-Type: application/json" \
    -d "{
        \"input\": \"Hello, this is a cloned voice.\",
        \"voice\": \"Junhao\",
        \"ref_audio\": \"data:audio/wav;base64,${REF_AUDIO}\",
        \"ref_text\": \"Exact transcript of the reference audio.\"
    }" --output cloned.wav

Using Python

import httpx

response = httpx.post(
    "http://localhost:8091/v1/audio/speech",
    json={
        "input": "你好，这是语音合成测试。",
        "voice": "Junhao",
        "response_format": "wav",
    },
    timeout=300.0,
)

with open("output.wav", "wb") as f:
    f.write(response.content)

Streaming

curl -X POST http://localhost:8091/v1/audio/speech \
    -H "Content-Type: application/json" \
    -d '{
        "input": "Hello, streaming output from MOSS-TTS-Nano.",
        "voice": "Ava",
        "stream": true,
        "response_format": "pcm"
    }' --no-buffer | play -t raw -r 48000 -e signed -b 16 -c 2 -

Note: MOSS-TTS-Nano outputs at 48 kHz stereo (2-channel).

API Parameters

MOSS-TTS-Nano uses the standard /v1/audio/speech endpoint.

Parameter	Type	Default	Description
input	string	required	Text to synthesize (ZH / EN / JA)
voice	string	"Junhao"	Built-in voice name (see table below)
response_format	string	"wav"	Audio format: wav, mp3, flac, pcm
ref_audio	string	null	Base64 data URL for custom voice cloning
ref_text	string	null	Transcript of reference audio (required when ref_audio is set)
stream	bool	false	Stream raw PCM chunks
max_new_tokens	int	4096	Maximum tokens to generate

Built-in Voice Presets

Voice	Language	Description
Junhao	ZH	Male, standard Mandarin
Zhiming	ZH	Male
Weiguo	ZH	Male
Xiaoyu	ZH	Female
Yuewen	ZH	Female
Lingyu	ZH	Female
Ava	EN	Female, American English
Bella	EN	Female
Adam	EN	Male
Nathan	EN	Male
Sakura	JA	Female
Yui	JA	Female
Aoi	JA	Female
Hina	JA	Female
Mei	JA	Female

Troubleshooting

1. libnvrtc.so.13: cannot open shared object file: torchaudio 2.10+ defaults to torchcodec which requires NVRTC. vLLM-Omni patches this automatically at model load time to use soundfile instead.
2. Connection refused: Ensure the server is running on the correct port.
3. Flashinfer version mismatch: Set FLASHINFER_DISABLE_VERSION_CHECK=1 if you see version warnings.
4. Out of memory: The default gpu_memory_utilization=0.3 is conservative. Increase it in the stage config if you have more VRAM available.