Piper-TTS Audiobook Script

This project is a one-command solution to convert large .txt documents into high-quality MP3 audiobooks entirely offline using Piper — a fast, local, open-source text-to-speech engine.

The script:

• Installs all prerequisites (pipx, ffmpeg, piper-tts)
• Downloads a chosen Piper voice model (default: female UK English — en_GB-cori-high)
• Splits large text into manageable chunks for Piper
• Synthesizes each chunk into audio
• Stitches the chunks together into a single MP3 file

---

📂 Project Structure

Piper-TTS-Script/
├── make\_audiobook.sh   # Main script
└── README.md           # This file

---

⚙️ Requirements

• Linux Mint / Ubuntu (or other Debian-based distro)
• Internet connection for the first run (to install packages and download the voice model)
• A .txt file containing your book or text to be converted

---

📥 Installation

1. Clone or download this repo:

   cd ~/Documents/GitHub
   git clone https://github.com/yourusername/Piper-TTS-Script.git
   

*(Or just manually create the folder and place `make_audiobook.sh` inside)*

2. **Make the script executable**:

   ```bash
   chmod +x ~/Documents/GitHub/Piper-TTS-Script/make_audiobook.sh
   ```

---

## 🗂 Preparing Your Text File

Place your text file somewhere accessible, e.g.:

```
~/Documents/audiobooks/mybook.txt
```

If you have a PDF or EPUB, convert it to plain text first:

```bash
# PDF to TXT
pdftotext mybook.pdf mybook.txt

# EPUB to TXT (requires calibre)
ebook-convert mybook.epub mybook.txt
```

---

## 🚀 Usage

Basic usage:

```bash
~/Documents/GitHub/Piper-TTS-Script/make_audiobook.sh ~/Documents/audiobooks/mybook.txt
```

* **First run**: Installs all dependencies and downloads the default voice model.
* **Output**: An MP3 file in the same directory as your text:

  ```
  ~/Documents/audiobooks/mybook.mp3
  ```

---

## 🔧 Configuration

At the top of `make_audiobook.sh` there is a **CONFIG** section where you can adjust:

| Setting                             | Description                                            |
| ----------------------------------- | ------------------------------------------------------ |
| `MODEL_NAME`                        | Name of the Piper voice model                          |
| `MODEL_FILE`                        | Path to your `.onnx` model file                        |
| `MODEL_ONNX_URL` / `MODEL_JSON_URL` | Download URLs for the model and metadata               |
| `LENGTH_SCALE`                      | Speech speed (1.0 = normal, <1 faster, >1 slower)      |
| `NOISE_SCALE`                       | Expressiveness (lower = flatter, higher = more varied) |
| `MAX_CHARS`                         | Max characters per chunk sent to Piper                 |
| `SILENCE_MS`                        | Silence gap between chunks in milliseconds             |
| `MP3_Q`                             | MP3 quality (VBR: 0=best, 2=high, 5=medium)            |

---

## 🎤 Changing the Voice

This script defaults to:

* **Female UK English** — `en_GB-cori-high`

To change:

1. Visit the official Piper voice list:
   [https://github.com/rhasspy/piper/blob/master/VOICES.md](https://github.com/rhasspy/piper/blob/master/VOICES.md)

2. Copy the `.onnx` and `.onnx.json` URLs for your chosen voice.

3. Edit the **CONFIG** section in `make_audiobook.sh` with the new:

   * `MODEL_NAME`
   * `MODEL_ONNX_URL`
   * `MODEL_JSON_URL`

Example for **Female US English (Lessac)**:

```bash
MODEL_NAME="en_US-lessac-high"
MODEL_ONNX_URL="https://huggingface.co/rhasspy/piper-voices/resolve/main/en/en_US/lessac/high/en_US-lessac-high.onnx"
MODEL_JSON_URL="https://huggingface.co/rhasspy/piper-voices/resolve/main/en/en_US/lessac/high/en_US-lessac-high.onnx.json"
```

---

## 🛠 Advanced Usage

Specify a custom voice model:

```bash
~/Documents/GitHub/Piper-TTS-Script/make_audiobook.sh ~/Documents/audiobooks/mybook.txt \
  --model ~/.local/share/piper/voices/en_US-lessac-high.onnx
```

Name the output file:

```bash
~/Documents/GitHub/Piper-TTS-Script/make_audiobook.sh ~/Documents/audiobooks/mybook.txt \
  --name my_custom_audiobook.mp3
```

---

## ⚠️ Limitations

* For **extremely large books** (>200k characters), processing can still take a while even with chunking.
* If the voice model URLs change, you’ll need to update them from [VOICES.md](https://github.com/rhasspy/piper/blob/master/VOICES.md).
* Piper’s pronunciation is very good but not perfect; some technical or foreign words may be read oddly.

---

## 📄 License

This script is released under the MIT License. Piper itself is licensed under the Mozilla Public License 2.0.

---

## 🙋‍♂️ Credits

* [Piper TTS](https://github.com/rhasspy/piper) — Open-source text-to-speech engine
* [ffmpeg](https://ffmpeg.org) — Audio conversion
* Script by **Your Name**