ChapterSplit Guide
Split large MP3 audiobook files into individual chapter tracks automatically, using embedded metadata or silence detection. Available on macOS and Windows.
What is ChapterSplit?
ChapterSplit is a desktop application for macOS and Windows that takes a single large MP3 audiobook file and divides it into individual chapter files. Many audiobooks arrive as one enormous file — sometimes 10–15 hours long — with no way to skip between chapters on a basic media player or device. ChapterSplit reads the file, finds where each chapter begins and ends, and outputs a clean set of numbered MP3 files you can navigate naturally.
It does this two ways: by reading embedded chapter markers already baked into the file's metadata, or by analysing the audio waveform to detect the natural pauses between chapters. Auto mode tries metadata first, then falls back to silence detection if no markers exist.
Reads embedded ID3 chapter markers for exact, instant splits with no audio analysis needed.
Analyses the waveform for sustained quiet gaps. Useful when metadata is missing, provided the recording has recognisable pauses.
Tries metadata first. Falls back to silence detection automatically. The right default for most users.
System requirements
- macOS 12.0 (Monterey) or later
- Supports MP3, M4A, AAC, FLAC, WAV, OGG
- 100 MB free disk space, 2 GB RAM recommended
- FFmpeg bundled — no separate install
- Available on the Mac App Store
- Windows 10 (version 1809) or later, 64-bit
- Supports MP3, M4A, AAC, FLAC, WAV, OGG
- 100 MB free disk space
- FFmpeg bundled — no separate install
- Available on the Microsoft Store
🍎 How to use ChapterSplit on macOS
The macOS version is a native Swift/SwiftUI app built to feel right at home on your Mac. Every step below corresponds to a screen you'll see inside the app.
Launch the app and check FFmpeg status
The Home tab appears immediately after launch. A green status badge confirms FFmpeg is ready. FFmpeg ships inside the app bundle, so you never need to install anything separately.
Start a new job
Click "New Job" on the Home tab. This opens the Job Setup view. If you have an unfinished draft from a previous session, a "Resume Draft" button will appear — tap it to pick up exactly where you left off.
Select your input files
Drag and drop audio files into the file list, or click Browse to use Finder. You can add multiple files from the same audiobook series. ChapterSplit accepts MP3, M4A, AAC, FLAC, WAV, and OGG formats on macOS. Files are processed in the order you add them.
Choose an output folder
Select where the split chapter files should be saved. macOS will ask for folder access once. ChapterSplit stores a security-scoped bookmark so it remembers that permission across restarts — you won't be asked again for the same folder.
Pick a split preset
Choose from Auto, Chapters (metadata), Silence Detection, or a custom silence configuration. Auto is right for most users. If your audiobook has no metadata at all, choose a silence preset — Balanced works well for the majority of commercially produced audiobooks.
Configure output options
Set chapter number padding (2-digit: 01, or 3-digit: 001), title format, whether to include the album name in filenames, cover art handling, and encoding. The Mac engine attempts stream copy first, then falls back to encoding when the source needs it. Safer Encoding uses a fixed bitrate and sample rate for difficult files.
Submit the job
Tap Start. The Progress tab takes over and shows a real-time progress bar, the name of the chapter currently being extracted, processing speed (e.g., 2.5×), and an ETA. You can cancel at any time without corrupting already-completed output files.
Review results
Once complete, the results screen lists every file created with its size and duration. Tap Open in Finder to jump straight to the output folder. The job is saved to your history (last 50 jobs) so you can review past splits from the Home tab at any time.
🪟 How to use ChapterSplit on Windows
The Windows version is built with Electron, React, and Tailwind CSS, following Microsoft's Fluent Design System. It uses a four-step wizard that walks you through every decision before processing begins.
Launch and check the home screen
The Home screen displays an FFmpeg status card at the top. A green checkmark with the detected version number means you're ready. Recent jobs appear below as cards with quick-action buttons.
Click New Split Job
Clicking "New Split Job" opens the four-step wizard. A step indicator along the top shows your position: Input → Output → Mode → Review.
Step 1 — Select input files
Drag and drop supported audio files into the drop zone, or click Browse Files. Each added file appears in a list below with its size and duration. Remove any file with the × button. For a multi-file audiobook, confirm the listening order before starting the job.
Step 2 — Configure output
Choose your output directory, set chapter number style (2-digit or 3-digit), pick the title format (number only, or with a 'Chapter' prefix), and select audio encoding. You'll see a live filename preview update instantly as you change settings — e.g., 001 - Chapter 01 - Harry Potter.mp3.
Step 3 — Choose split mode
Select Auto (recommended), Chapters Only, or Silence Detection. If you choose Silence Detection, a preset dropdown appears — Balanced is right for most audiobooks. An Advanced Settings link expands a panel for fine-grained control over threshold, minimum silence duration, pre-roll, and minimum segment length.
Step 4 — Review and start
The Review step shows the complete split plan before anything runs. You can see the number of chapters detected, estimated file sizes, and the exact output filenames. If something looks wrong, step back and adjust. When ready, click Start Split.
Monitor progress
The Progress view shows a large progress bar, the current chapter being extracted (e.g., Chapter 12 of 27), processing speed in real time, and an ETA countdown. An expanding log lists each completed chapter as it finishes. Cancel is available at any point.
View results
The results screen summarises total files created, total size, and processing duration. Click Open Folder to jump to the output in Windows Explorer. An Export Playlist button creates an M3U file you can load directly into a media player.
Split modes explained
ChapterSplit offers three core modes. Understanding when to use each one saves you from getting unexpected results.
| Mode | How it works | Best for |
|---|---|---|
| Auto | Tries metadata chapters first. Falls back to silence detection if none found. | Default choice when you do not yet know whether the file contains usable chapter metadata. |
| Chapters (Metadata) | Reads ID3/M4A chapter markers embedded in the file. No audio analysis performed. | DRM-free files with a valid embedded chapter table. Fast and timestamp-driven. |
| Silence Detection | Analyses the waveform to find quiet gaps between chapters using configurable threshold and duration settings. | Self-published audiobooks, ripped CDs, files without embedded chapter metadata. |
Silence detection presets
When silence detection is active, these presets control how the waveform analysis runs. Available on both macOS and Windows. All values are adjustable in Custom mode.
More splits, shorter segments. Useful when pauses between chapters are brief.
The sweet spot for most commercially produced audiobooks.
Fewer splits, longer segments. Ignores short pauses inside chapters.
File naming and numbering
ChapterSplit outputs files in a consistent, sortable format. You control the exact pattern.
NNN - Chapter Title - Album Name.mp301 - Chapter 01 - Harry Potter.mp3001 - Chapter 001 - Harry Potter.mp3001 - 01 - Harry Potter.mp3001 - Chapter 01 - Harry Potter.mp3Global vs per-file numbering
When processing multiple files in one job, global numbering gives you a single continuous sequence across all discs (disc 1 ends at chapter 027, disc 2 starts at 028). Per-file numbering resets to chapter 01 for each input file. Both options are available on macOS and Windows.
Cover art handling
ChapterSplit gives you three options for embedded cover art in the output files.
Extracts the cover art from the source file and embeds it into each output chapter. Files are slightly larger but look great in any media player.
Supply your own PNG or JPG image. Every output chapter gets your image embedded instead of the original. Useful when the source art is low resolution.
Output files contain no embedded cover art. Smallest possible file size.
~/Library/Application Support/ChapterSplit/cover-art-cache/.macOS vs Windows: key differences
Both editions share the same core purpose and split modes, but they use different native application and encoding implementations. These are the meaningful differences between platforms.
| Feature | 🍎 macOS | 🪟 Windows |
|---|---|---|
| Supported input formats | MP3, M4A, AAC, FLAC, WAV, OGG | MP3, M4A, AAC, FLAC, WAV, OGG |
| UI framework | SwiftUI (native) | Electron + React |
| Setup flow | Job setup view with Quick Start option | 4-step wizard with live filename preview |
| Safer encoding mode | ✓ Fixed bitrate/sample rate fallback | ✓ Fixed bitrate/sample rate fallback |
| System tray | — | ✓ Minimise to tray, background processing |
| Notifications | macOS notification centre | Windows toast notifications |
| Folder permissions | Security-scoped bookmarks (ask once) | Standard file picker |
| Job history | Last 50 jobs | Recent jobs panel |
| Subscriptions | Apple App Store | Microsoft Store |
| Minimum OS | macOS 12.0 Monterey | Windows 10 v1809 |
Audio encoding options
The current Mac and Windows engines use different output strategies. The Mac edition attempts stream copy first and can fall back to encoding. The Windows edition creates MP3 chapters with high-quality VBR encoding and retries certain failures with safer fixed-bitrate settings.
Copies compressed audio packets without another encode when the source permits it. This is fast and avoids another lossy generation, but it cannot improve the quality already present in the source.
Creates MP3 chapter audio with high-quality VBR settings. If a known VBR encoder failure occurs, ChapterSplit retries with a fixed bitrate and sample rate for a more conservative output.
Troubleshooting
No chapters detected in Auto mode
This means the file has no embedded chapter metadata, and silence detection found no pauses long enough to split on. Try the following in order:
- Try another silence preset and review how its threshold and required duration change the result.
- Adjust one control at a time; a less-negative threshold accepts more of the recording as quiet, while a more-negative threshold requires genuinely quieter audio.
- Open the file in a media player and listen. If there genuinely are no gaps (e.g., continuous background music), silence detection cannot work — use a tool to manually add chapter markers first.
Output files are larger than the source
This is almost always cover art. If your source has 300 KB of embedded artwork and you split into 27 chapters, each output file carries its own copy — adding around 8 MB in total overhead. Toggle cover art to Remove in settings if you want the smallest possible files.
macOS keeps asking for folder permission after restart
This is resolved in the current version using security-scoped bookmarks. If you're still seeing the prompt, ensure you're running the latest App Store version. Grant access once and ChapterSplit stores a bookmark so it never needs to ask again for that folder.
Chapters are the wrong length (much too short or too long)
Chapters too short: increase the minimum segment length so very short detections are filtered out. Chapters too long: reduce the required silence duration or use a less-negative threshold so more quiet passages qualify. Change one control at a time and review the result.
Job fails with no specific error (Windows)
Check that the output folder exists and is writable. Verify you have at least 2× the source file size available as free disk space. Check logs at %APPDATA%\ChapterSplit\logs\ for detailed diagnostics.
Unsupported or unreadable input (Windows)
The current Windows code accepts MP3, M4A, AAC, FLAC, WAV, and OGG input. A supported extension does not guarantee that every damaged or unusual stream can be decoded, so test the file in a normal player and try a representative sample before starting a batch.
Frequently asked questions
The Mac and Windows editions use different store and licensing arrangements. Prices and trial terms can change, so use the platform-specific store buttons below for the current offer rather than relying on a price copied into this guide.
It depends on the platform. The current Mac engine attempts stream copy first and falls back to encoding when needed. The current Windows engine creates MP3 chapters with high-quality VBR encoding and offers a safer fixed-bitrate fallback.
Yes. Add multiple files to a single job and ChapterSplit processes them sequentially in the queue. On macOS you can queue additional jobs before the first one finishes. Global chapter numbering across all files is available in settings.
ChapterSplit never modifies the source file — it only creates new output files. If the result isn't right, delete the output folder, adjust your settings, and run the job again. Your source file is always untouched.
The current repositories list the same common input extensions on both platforms: MP3, M4A, AAC, FLAC, WAV, and OGG. Output encoding and advanced job features differ, so check the platform comparison rather than assuming complete implementation parity.
Chapter metadata is always more reliable when present — it uses exact timestamps embedded by whoever created the audiobook. Silence detection is an analysis of the audio waveform, which means it depends on the quality of the recording and your threshold settings. Use metadata when available, silence detection as the fallback.
Ready to split your audiobook?
Choose the ChapterSplit edition for your platform. The store pages show the current price, trial, and purchase terms.