Generic TTS engines like Google TTS, Microsoft Azure TTS, or Amazon Polly can convert eBooks into audiobooks, but their voices often lack natural, human-like nuances. This guide introduces a superior tool that delivers higher-quality, more natural-sounding audiobooks from EPUB files.
1. Introduce the Frontier TTS Tool - Kokoro-82M
Kokoro is a compact TTS model with 82 million parameters, designed to deliver high-quality speech synthesis efficiently. It currently supports American English, British English, French, Korean, Japanese, and Chinese, offering a variety of high-quality voices.
Compared to generic TTS models, Kokoro-82M achieves high-quality TTS with a smaller model size and less training data. Its open-source nature make it a compelling choice for users seeking effective TTS solutions. Below is a comparison table between Kokoro-82M and Generic TTS Systems:
| Feature | Kokoro-82M | Generic TTS Systems |
|---|---|---|
| Voice Quality | High-quality, expressive, near-human | Basic to decent, less expressive |
| Customization | Language, voice, speed, and chapter selection | Limited (some allow voice/speed choice) |
| Contextual Understanding | Limited, but better suited for long text | Limited, often monotone |
| Languages | Multiple supported | Varies by provider |
| Ease of Use | Requires setup and familiarity with CLI | Easy to use, plug-and-play |
| Cost | Free | Often pay-per-character |
| Time to Generate | Medium (depends on e-book size) | Fast for short text, slower for long |
| System Requirements | Requires Kokoro-82M model, ffmpeg, and Python | None |
| Who Uses Them | Tech-savvy users, audiobook hobbyists | General users, casual text readers |
2. How to Convert EPUB into Audiobook
This tutorial is a simplified version, designed to be straightforward and easy to follow.
Step 1Download Requirements
Download the following three files and save them to your desktop: 1. kokoro-v0_19.onnx, 2. voices.json, 3. audiblez.py
Download audiblez.py here: Open audiblez.py raw file, Press Ctrl + S (Windows) or Command + S (Mac), it should be saved as audiblez.py.
Download kokoro-v0_19.onnx here: kokoro-v0_19.onnx
Download voices.json here: voices.json
After downloading the three files mentioned above, create a new folder and place these three files along with your EPUB file into it. The folder should look like this:
How to Remove DRM from EPUB Files?
All EPUB to Audio tool only support DRM-free EPUBs. For DRM-protected EPUBs, you can refer to this guide to remove DRM.
Step 2Download and Install Python
Audiblez.py generates .m4b audiobooks from regular .epub e-books, using Kokoro's high-quality speech synthesis. To run the script, you need to have Python installed.
1. Download python here: Python
2. Double-click the installer to start the setup process. Important: On the first screen, check the box that says "Add Python to PATH". This step ensures you can run python commands directly from the Command Prompt.
Step 3Convert EPUB to Audiobooks
Right-click on the blank area of the newly created folder and select "Open in Terminal" from the context menu.
To turn EPUB into audiobooks, run this in the terminal window: python audiblez.py book.epub -l en-gb -v af_sky (replace book.epub with your EPUB file name)
This script allows you to specify the language (-l),
voice (-v),
and playback speed (-s) for text-to-speech synthesis.
Supported languages include US en-us,
GB en-gb,
FR fr-fr,
JP ja-jp,
KR ko-kr,
and CN zh-cn.
Example voices include af,
af_bella,
af_nicole,
af_sarah,
and af_sky.
Playback speed can be adjusted within a range of 0.1 to 2.0.
It will first create a bunch of book_chapter_1.wav, book_chapter_2.wav, etc. files in the same directory, and at the end it will produce a book.m4b file with the whole book. It will only produce the .m4b file if you have ffmpeg installed on your machine.
How to Turn EPUB into a Single M4B File?
To combine all the chapters into a single M4B file, follow these steps to download FFmpeg and add it to the system path.
1. Download FFmpeg here: FFmpeg
2.Extract the .zip file to a folder, e.g., C:\ffmpeg.
3. Add FFmpeg to the System Path:
Open the Start menu, search for "Environment Variables" and select Edit the system environment variables.
In the System Properties window, click "Environment Variables".
Under System variables, find and select the Path variable, then click Edit. Click New, and add the bin directory of FFmpeg (e.g., C:\ffmpeg\bin). Click OK to save changes and close all dialog boxes.
4. Run this again: python audiblez.py book.epub -l en-gb -v af_sky
Amy Lopez crafts informative articles on eBooks and eReaders, uncovering optimal methods to enhance your eBook reading experience, and eagerly shares her findings with you.
