## Overview
FireRedTTS‑2 is a long-form streaming TTS system for **multi-speaker dialogue generation**, delivering stable, natural speech with reliable speaker switching and context-aware prosody.
## Highlight🔥
- **Long Conversational Speech Generation**: It currently supports 3 minutes dialogues with 4 speakers and can be easily scaled to longer conversations
with more speakers by extending training corpus.
- **Multilingual Support**: It supports multiple languages including English, Chinese, Japanese, Korean, French, German, and Russian. Support zero-shot voice cloning for cross-lingual and code-switching scenarios.
- **Ultra-Low Latency**: Building on the new **12.5Hz streaming** speech tokenizer, we employ a dual-transformer architecture that operates on a text–speech interleaved sequence, enabling flexible sentence-bysentence generation and reducing first-packet latency，Specifically, on an L20 GPU, our first-packet latency as low as 140ms while maintaining high-quality audio output.
- **Strong Stability**：Our model achieves high similarity and low WER/CER in both monologue and dialogue tests.
- **Random Timbre Generation**:Useful for creating ASR/speech interaction data.
## Demo Examples
For more examples, see [demo page](https://fireredteam.github.io/demos/firered_tts_2/).
## News
- [2025/09/12] 🔥 **We have added a UI tool to the dialogue generation.**
- [2025/09/08] 🔥 We release the [pre-trained checkpoints](https://huggingface.co/FireRedTeam/FireRedTTS2) and inference code.
- [2025/09/02] 🔥 We release the [technical report](https://arxiv.org/abs/2509.02020) and [demo page](https://fireredteam.github.io/demos/firered_tts_2/)
## Roadmap
- [x] 2025/09
- [x] Release the pre-trained checkpoints and inference code.
- [x] Add web UI tool.
- [ ] 2025/10
- [ ] Release a base model with enhanced multilingual support.
- [ ] **Provide fine-tuning code & tutorial for specific dialogue/multilingual data.**
- [ ] **End-to-end text-to-blog pipeline.**
## Install & Model Download
### Clone and install
- **Clone the repo**
``` sh
git clone https://github.com/FireRedTeam/FireRedTTS2.git
cd FireRedTTS2
```
- **Create Conda env**:
``` sh
conda create --name fireredtts2 python==3.11
conda activate fireredtts2
# Step 1. PyTorch Installation (if required)
pip install torch==2.7.1 torchvision==0.22.1 torchaudio==2.7.1 --index-url https://download.pytorch.org/whl/cu126
# Step 2. Install Dependencies
pip install -e .
pip install -r requirements.txt
```
- **Model download**
```sh
git lfs install
git clone https://huggingface.co/FireRedTeam/FireRedTTS2 pretrained_models/FireRedTTS2
```
## Basic Usage
**Dialogue Generation with Web UI**
Generate dialogue through an easy-to-use web interface that supports both voice cloning and randomized voices.
```sh
python gradio_demo.py --pretrained-dir "./pretrained_models/FireRedTTS2"
```
**Dialogue Generation**
```python
import os
import sys
import torch
import torchaudio
from fireredtts2.fireredtts2 import FireRedTTS2
device = "cuda"
fireredtts2 = FireRedTTS2(
pretrained_dir="./pretrained_models/FireRedTTS2",
gen_type="dialogue",
device=device,
)
text_list = [
"[S1]那可能说对对，没有去过美国来说去去看到美国线下。巴斯曼也好，沃尔玛也好，他们线下不管说，因为深圳出去的还是电子周边的会表达，会发现哇对这个价格真的是很高呀。都是卖三十五美金、四十美金，甚至一个手机壳，就是二十五美金开。",
"[S2]对，没错，我每次都觉得不不可思议。我什么人会买三五十美金的手机壳？但是其实在在那个target啊，就塔吉特这种超级市场，大家都是这样的，定价也很多人买。",
"[S1]对对，那这样我们再去看说亚马逊上面卖卖卖手机壳也好啊，贴膜也好，还包括说车窗也好，各种线材也好，大概就是七块九九或者说啊八块九九，这个价格才是卖的最多的啊。因为亚马逊的游戏规则限定的。如果说你卖七块九九以下，那你基本上是不赚钱的。",
"[S2]那比如说呃除了这个可能去到海外这个调查，然后这个调研考察那肯定是最直接的了。那平时我知道你是刚才建立了一个这个叫做呃rean的这样的一个一个播客，它是一个英文的。然后平时你还听一些什么样的东西，或者是从哪里获取一些这个海外市场的一些信息呢？",
"[S1]嗯，因为做做亚马逊的话呢，我们会关注很多行业内的东西。就比如说行业有什么样亚马逊有什么样新的游戏规则呀。呃，物流的价格有没有波动呀，包括说有没有什么新的评论的政策呀，广告有什么新的打法呀？那这些我们会会关关注很多行业内部的微信公众号呀，还包括去去查一些知乎专栏的文章呀，以及说我们周边有很多同行。那我们经常会坐在一起聊天，看看信息有什么共享。那这个是关注内内的一个方式。",
]
prompt_wav_list = [
"examples/chat_prompt/zh/S1.flac",
"examples/chat_prompt/zh/S2.flac",
]
prompt_text_list = [
"[S1]啊，可能说更适合美国市场应该是什么样子。那这这个可能说当然如果说有有机会能亲身的去考察去了解一下，那当然是有更好的帮助。",
"[S2]比如具体一点的，他觉得最大的一个跟他预想的不一样的是在什么地方。",
]
all_audio = fireredtts2.generate_dialogue(
text_list=text_list,
prompt_wav_list=prompt_wav_list,
prompt_text_list=prompt_text_list,
temperature=0.9,
topk=30,
)
torchaudio.save("chat_clone.wav", all_audio, 24000)
```
**Monologue Generation**
```python
import os
import sys
import torch
import torchaudio
from fireredtts2.fireredtts2 import FireRedTTS2
device = "cuda"
lines = [
"Hello everyone, welcome to our newly launched FireRedTTS2. It supports multiple languages including English, Chinese, Japanese, Korean, French, German, and Russian. Additionally, this TTS model features long-context dialogue generation capabilities.",
"如果你厌倦了千篇一律的AI音色，不满意于其他模型语言支持不够丰富，那么本项目将会成为你绝佳的工具。",
"ランダムな話者と言語を選択して合成できます",
"이는 많은 인공지능 시스템에 유용합니다. 예를 들어, 제가 다양한 음성 데이터를 대량으로 생성해 여러분의 ASR 모델이나 대화 모델에 풍부한 데이터를 제공할 수 있습니다.",
"J'évolue constamment et j'espère pouvoir parler davantage de langues avec plus d'aisance à l'avenir.",
]
fireredtts2 = FireRedTTS2(
pretrained_dir="./pretrained_models/FireRedTTS2",
gen_type="monologue",
device=device,
)
# random speaker
for i in range(len(lines)):
text = lines[i].strip()
audio = fireredtts2.generate_monologue(text=text)
# adjust temperature & topk
# audio = fireredtts2.generate_monologue(text=text, temperature=0.8, topk=30)
torchaudio.save(str(i) + ".wav", audio.cpu(), 24000)
# # voice clone
# for i in range(len(lines)):
# text = lines[i].strip()
# audio = fireredtts2.generate_monologue(
# text=text,
# prompt_wav=
