moss-tts-nano-speech
MOSS-TTS-Nano Speech Generation Skill
Skill by ara.so — Daily 2026 Skills collection.
MOSS-TTS-Nano is an open-source multilingual tiny TTS model (0.1B parameters) from MOSI.AI and the OpenMOSS team. It uses an Audio Tokenizer + LLM autoregressive pipeline to generate 48 kHz stereo speech in real time, supports 20 languages, voice cloning, streaming inference, and runs on CPU without a GPU.
Installation
Conda (recommended)
conda create -n moss-tts-nano python=3.12 -y
conda activate moss-tts-nano
git clone https://github.com/OpenMOSS/MOSS-TTS-Nano.git
cd MOSS-TTS-Nano
pip install -r requirements.txt
pip install -e .
Fix WeTextProcessing if it fails
conda install -c conda-forge pynini=2.1.6.post1 -y
pip install git+https://github.com/WhizZest/WeTextProcessing.git
After pip install -e . the moss-tts-nano CLI command is available in the active environment.
Model Weights
Models are auto-downloaded from Hugging Face on first run:
- TTS model:
OpenMOSS-Team/MOSS-TTS-Nano - Audio tokenizer:
OpenMOSS-Team/MOSS-Audio-Tokenizer-Nano
ModelScope mirrors are available at openmoss/MOSS-TTS-Nano and openmoss/MOSS-Audio-Tokenizer-Nano.
CLI Commands
Generate speech (voice clone mode)
moss-tts-nano generate \
--prompt-speech assets/audio/zh_1.wav \
--text "欢迎关注模思智能、上海创智学院与复旦大学自然语言处理实验室。"
Output defaults to generated_audio/moss_tts_nano_output.wav.
Generate from a text file (long-form)
moss-tts-nano generate \
--prompt-speech assets/audio/zh_1.wav \
--text-file my_script.txt \
--output output.wav
Launch local web demo
moss-tts-nano serve
# or directly:
python app.py
Opens at http://127.0.0.1:18083 — model stays loaded in memory for fast repeated requests.
Direct Python entrypoint
python infer.py \
--prompt-audio-path assets/audio/zh_1.wav \
--text "Hello, this is a test of MOSS-TTS-Nano."
Output: generated_audio/infer_output.wav
Python API Usage
Basic voice clone inference
from infer import MossTTSNanoInference
# Initialize once (downloads weights on first run)
tts = MossTTSNanoInference()
# Voice clone: synthesize text in the style of the reference audio
audio = tts.infer(
text="欢迎使用MOSS语音合成系统。",
prompt_audio_path="assets/audio/zh_1.wav",
)
# Save output
import soundfile as sf
sf.write("output.wav", audio, samplerate=48000)
English voice clone
from infer import MossTTSNanoInference
tts = MossTTSNanoInference()
audio = tts.infer(
text="Welcome to MOSS TTS Nano, a tiny but capable text to speech model.",
prompt_audio_path="assets/audio/en_sample.wav",
)
import soundfile as sf
sf.write("english_output.wav", audio, samplerate=48000)
Streaming inference (low latency)
from infer import MossTTSNanoInference
import soundfile as sf
import numpy as np
tts = MossTTSNanoInference()
chunks = []
for audio_chunk in tts.infer_stream(
text="This sentence is generated chunk by chunk for low latency playback.",
prompt_audio_path="assets/audio/en_sample.wav",
):
chunks.append(audio_chunk)
# process or play chunk in real time here
full_audio = np.concatenate(chunks)
sf.write("streamed_output.wav", full_audio, samplerate=48000)
Long-text synthesis with chunked voice cloning
from infer import MossTTSNanoInference
tts = MossTTSNanoInference()
long_text = """
MOSS-TTS-Nano supports long-form synthesis through automatic chunking.
Each chunk uses the same reference voice, producing consistent speaker identity
across the entire output even for multi-paragraph documents.
"""
audio = tts.infer(
text=long_text,
prompt_audio_path="assets/audio/en_sample.wav",
)
import soundfile as sf
sf.write("long_form_output.wav", audio, samplerate=48000)
FastAPI HTTP endpoint usage
When the server is running (moss-tts-nano serve or python app.py):
import requests
import base64
import soundfile as sf
import io
import numpy as np
# Read reference audio as base64
with open("assets/audio/zh_1.wav", "rb") as f:
ref_audio_b64 = base64.b64encode(f.read()).decode()
response = requests.post(
"http://127.0.0.1:18083/generate",
json={
"text": "你好,这是一个语音合成测试。",
"prompt_audio_base64": ref_audio_b64,
},
)
data = response.json()
audio_bytes = base64.b64decode(data["audio_base64"])
audio_array, sr = sf.read(io.BytesIO(audio_bytes))
sf.write("api_output.wav", audio_array, samplerate=sr)
Streaming HTTP response (real-time web playback)
import requests
with open("assets/audio/zh_1.wav", "rb") as f:
ref_audio_b64 = __import__("base64").b64encode(f.read()).decode()
with requests.post(
"http://127.0.0.1:18083/generate_stream",
json={
"text": "流式语音合成示例,适合实时播放场景。",
"prompt_audio_base64": ref_audio_b64,
},
stream=True,
) as resp:
with open("stream_output.wav", "wb") as out:
for chunk in resp.iter_content(chunk_size=4096):
out.write(chunk)
Supported Languages
| Code | Language | Code | Language | Code | Language |
|---|---|---|---|---|---|
| zh | Chinese | en | English | de | German |
| es | Spanish | fr | French | ja | Japanese |
| it | Italian | hu | Hungarian | ko | Korean |
| ru | Russian | fa | Persian | ar | Arabic |
| pl | Polish | pt | Portuguese | cs | Czech |
| da | Danish | sv | Swedish | el | Greek |
| tr | Turkish |
The language is inferred automatically from the input text and the reference audio. No explicit language code parameter is required for basic usage.
Architecture Overview
- Pipeline: Audio Tokenizer + LLM (pure autoregressive)
- Audio Tokenizer: MOSS-Audio-Tokenizer-Nano (~20M params), CNN-free causal Transformer (Cat architecture)
- Output: 48 kHz, 2-channel (stereo)
- Token rate: 12.5 Hz token stream
- Codebooks: RVQ with 16 codebooks (0.125 kbps – 2 kbps)
- LLM: ~0.1B parameters total
Key CLI Flags
| Flag | Alias | Description |
|---|---|---|
--prompt-audio-path |
— | Path to reference WAV for voice cloning (infer.py) |
--prompt-speech |
— | Same purpose in moss-tts-nano generate CLI |
--text |
— | Input text string |
--text-file |
— | Path to plain text file for long-form synthesis |
--output |
— | Output WAV file path (default varies by entrypoint) |
Common Patterns
Pattern: Batch synthesis with one reference voice
from infer import MossTTSNanoInference
import soundfile as sf
tts = MossTTSNanoInference()
ref = "assets/audio/zh_1.wav"
sentences = [
"第一句话,用于批量合成测试。",
"第二句话,保持相同的音色。",
"第三句话,输出独立的音频文件。",
]
for i, sentence in enumerate(sentences):
audio = tts.infer(text=sentence, prompt_audio_path=ref)
sf.write(f"output_{i:02d}.wav", audio, samplerate=48000)
print(f"Saved output_{i:02d}.wav")
Pattern: Real-time playback with sounddevice
import sounddevice as sd
import numpy as np
from infer import MossTTSNanoInference
tts = MossTTSNanoInference()
buffer = []
for chunk in tts.infer_stream(
text="Real-time playback example using sounddevice.",
prompt_audio_path="assets/audio/en_sample.wav",
):
buffer.append(chunk)
audio = np.concatenate(buffer)
sd.play(audio, samplerate=48000)
sd.wait()
Pattern: Gradio integration
import gradio as gr
import soundfile as sf
import numpy as np
import io
from infer import MossTTSNanoInference
tts = MossTTSNanoInference()
def synthesize(reference_audio_path: str, text: str):
audio = tts.infer(text=text, prompt_audio_path=reference_audio_path)
# Return as (sample_rate, numpy_array) tuple for Gradio Audio component
return (48000, audio)
demo = gr.Interface(
fn=synthesize,
inputs=[
gr.Audio(type="filepath", label="Reference Voice"),
gr.Textbox(label="Text to synthesize"),
],
outputs=gr.Audio(label="Generated Speech"),
title="MOSS-TTS-Nano Voice Clone",
)
demo.launch()
Troubleshooting
WeTextProcessing install fails
# Use conda to get pynini, then install from source
conda install -c conda-forge pynini=2.1.6.post1 -y
pip install git+https://github.com/WhizZest/WeTextProcessing.git
Model download is slow or fails
Set HF_ENDPOINT to a mirror if Hugging Face is unreachable:
export HF_ENDPOINT=https://hf-mirror.com
python infer.py --prompt-audio-path assets/audio/zh_1.wav --text "测试"
Or use ModelScope:
pip install modelscope
Then point model paths to openmoss/MOSS-TTS-Nano and openmoss/MOSS-Audio-Tokenizer-Nano.
Out of memory on CPU
- Use streaming inference (
infer_stream) to reduce peak memory. - Reduce chunk size for long text inputs — the model handles chunked voice cloning automatically.
- Close other applications; the model needs ~1–2 GB RAM.
Audio output is silent or corrupt
- Ensure the reference WAV is a clean mono or stereo file, 16-bit or float32, any sample rate (it will be resampled).
- Minimum reference audio duration: ~3–5 seconds for reliable voice cloning.
- Avoid reference audio with heavy background noise.
moss-tts-nano command not found
# Re-run editable install inside the active conda env
pip install -e .
which moss-tts-nano # should resolve now
Port conflict for web demo
# Default port is 18083; check what occupies it
lsof -i :18083
# Kill if needed, then relaunch
moss-tts-nano serve
Output Defaults
| Entrypoint | Default output path |
|---|---|
python infer.py |
generated_audio/infer_output.wav |
moss-tts-nano generate |
generated_audio/moss_tts_nano_output.wav |
python app.py / moss-tts-nano serve |
returned via HTTP response |
The generated_audio/ directory is created automatically if it does not exist.