bpm4b 9.0.2

MP3 to M4B Audiobook Converter - Convert MP3 files to M4B format with chapter support

BPM4B - Professional Multimedia Suite (v9.0.0)

A professional multimedia processing suite for converting MP3 to M4B, M4B to MP3, and generating AI Audiobooks with high-fidelity TTS and automatic chapter support.

Available in two versions:

• Python (Flask): pip install bpm4b then bpm4b
• Node.js (Express): npm install -g bpm4b then bpm4b

Installation

Python Version (Original)

pip install bpm4b
bpm4b web

Node.js Version

npm install -g bpm4b
bpm4b web

Or for local development:

git clone https://github.com/jdjchelp-jpg/nodebpm4b.git
cd nodebpm4b
npm install
npm start

Update:

# Update Python version
pip install --upgrade bpm4b

# Update Node.js version
npm update -g bpm4b

Features

🎯 Unified Smart Mode

• Single toggle switch: Conversion Mode vs Chapter Builder Only
• Automatic chapter attachment to MKV/M4B output when conversion mode is ON
• Standalone timestamp generator when mode is OFF

📁 File Conversion Section

• MP3 to M4B: Convert MP3 files to audiobook format with embedded chapters
• M4B to MP3: High-fidelity conversion from M4B/M4A containers to MP3 (NEW in v9)
• Document to Audiobook: Generate high-quality voiceovers from PDF/Text using Kokoro-82M AI (NEW in v9)
• Drag-and-drop file upload for all tools
• Real-time progress monitoring with SSE (Server-Sent Events)
• Visual progress bar and live terminal logging

⏱ Automatic Chapter Builder

• Always enabled - core functionality
• Enter chapter title and duration (minutes or seconds toggle)
• System automatically:
  • Converts input to proper format
  • Accumulates duration to cumulative total
  • Calculates next chapter start timestamp
  • Generates proper HH:MM:SS format
• No manual math required - all timestamps auto-generate
• Batch import/export chapter lists
• Real-time preview updates

⚙ Settings Panel

• Dark / Light mode toggle
• Modern toggle switches (not checkboxes)
• Glassmorphism card design
• Smooth animations and transitions
• Responsive layout optimized for desktop

🚀 Performance Improvements

• Faster parsing with optimized algorithms
• Non-blocking UI with background conversion
• Proper error handling and validation
• File size validation before processing
• Automatic cleanup of temporary files

📋 Professional Features

• Copy-to-clipboard buttons for generated commands
• Real-time updating preview panel
• FFmpeg command preview (self-service mode)
• Export chapters to .txt format
• Modern, clean, professional SaaS-like interface

Prerequisites

Node.js Version

No additional prerequisites needed! FFmpeg is bundled with the Node.js version, so it works out of the box.

Python Version (Original)

• Python 3.8+
• FFmpeg (required for MP3 to M4B conversion)

Installing FFmpeg (Python Version Only)

Windows:

1. Go to https://www.gyan.dev/ffmpeg/builds/ (recommended Windows builds)
2. Download "ffmpeg-git-full.7z" or "ffmpeg-release-full.7z"
3. Extract the archive using 7-Zip or similar
4. Open the extracted folder, navigate to the bin folder
5. Copy the path to the bin folder (contains ffmpeg.exe)
6. Add to PATH:
   • Press Win + X, select "System"
   • Click "Advanced system settings"
   • Click "Environment Variables"
   • Under "System variables", find and select "Path", click "Edit"
   • Click "New" and paste the path to the bin folder
   • Click OK on all windows
7. Open a new command prompt and verify: ffmpeg -version

macOS:

brew install ffmpeg

Ubuntu/Debian:

sudo apt-get update
sudo apt-get install ffmpeg

Note: The Python version requires FFmpeg. The Node.js version includes FFmpeg automatically.

Usage

Web Interface

Start the web server and open your browser to http://localhost:5000:

# Start the server
bpm4b web

# Or with custom options
bpm4b web --port 8080
bpm4b web --host 127.0.0.1 --debug

The web interface allows you to:

• Upload MP3 files through a simple form
• Add custom chapter markers with titles and timestamps
• Download the converted M4B audiobook

Command Line (No Web Interface)

Convert MP3 to M4B directly from the terminal:

# Basic conversion
bpm4b convert input.mp3 output.m4b

# With chapter markers
bpm4b convert input.mp3 output.m4b --chapter "Introduction" 0
bpm4b convert input.mp3 output.m4b --chapter "Chapter 1" 3600 --chapter "Chapter 2" 7200

# Multiple chapters
bpm4b convert book.mp3 book.m4b \\
  --chapter "Prologue" 0 \\
  --chapter "Chapter 1" 300 \\
  --chapter "Chapter 2" 1800

# Multiple chapters with MM:SS format
bpm4b convert book.mp3 book.m4b \\
 --chapter "Prologue" "0:00" \\
 --chapter "Chapter 1" "5:00" \\
 --chapter "Chapter 2" "30:00"

# Mixed formats (seconds and MM:SS)
bpm4b convert book.mp3 book.m4b \\
 --chapter "Intro" 0 \\
 --chapter "Chapter 1" "6:30" \\
 --chapter "Chapter 2" 3600

Chapter start times accept:

• Seconds as integer (e.g., 390)
• Minutes:seconds format (e.g., "6:30" or "6:30.5" for fractional seconds)

Using Python Module

Alternatively, you can run it as a Python module:

python -m bpm4b.cli web --port 5000
python -m bpm4b.cli convert input.mp3 output.m4b

Using the CLI (Package Installation)

After installing with pip install -e ., use the bpm4b command:

# Start web interface
bpm4b web

# Web interface with options
bpm4b web --port 8080
bpm4b web --host 127.0.0.1 --debug

# Convert MP3 to M4B directly
bpm4b convert input.mp3 output.m4b
bpm4b convert input.mp3 output.m4b --chapter "Chapter 1" 0

# Show help
bpm4b --help
bpm4b web --help
bpm4b convert --help

Using Python Module

Alternatively, you can run it as a Python module:

python -m bpm4b.cli web --port 5000
python -m bpm4b.cli convert input.mp3 output.m4b

Using the Traditional Method

If you installed dependencies only (without the package):

python app.py

Then open your browser and navigate to:

http://localhost:5000

Using the Tool

Once the server is running:

MP3 to M4B: Upload an MP3 file, add chapters using the automatic chapter builder, and click "Convert to M4B"

• Automatically converts to M4B format (iTunes/Apple Books compatible)
• Chapters automatically embedded with titles and timestamps
• Uses FFmpeg for high-quality AAC audio (64kbps - 256kbps)

M4B to MP3: Upload an M4B/M4A file and convert it to a standard MP3

• High-fidelity conversion using the libmp3lame encoder
• Perfect for playback on legacy devices or sharing

Audiobook Gen: Upload a PDF or Text document to generate a full audiobook

• Powered by Kokoro-82M Local TTS engine
• High-quality, human-like voice synthesis
• Automatic chapter detection and manifest generation

API Endpoints

POST /api/mp3-to-m4b

Converts an MP3 file to M4B with optional chapters.

Form Data:

• mp3_file: The MP3 file to convert
• chapters (optional): JSON array of chapter objects. start_time accepts seconds (number) or MM:SS format (string):

[
  {"title": "Chapter 1", "start_time": 0},
  {"title": "Chapter 2", "start_time": "6:30"},
  {"title": "Chapter 3", "start_time": 3600}
]

POST /api/convert

Converts MP3 to M4B or M4B to MP3.

Form Data:

• source_file: The file to convert
• output_name: Custom filename
• audio_quality: Bitrate (e.g., '128k', '256k')
• chapters (optional): JSON array of chapter objects.

POST /api/generate-audiobook

Generates an audiobook from a document.

Form Data:

• doc_file: The PDF or Text file
• voice: Selection from available Kokoro voices
• output_name: Custom filename

GET /api/health

Health check endpoint. Returns JSON with status and FFmpeg availability.

Response: Returns an M4B file as a download.

Project Structure

Python Version

.
├── bpm4b/              # Main package directory
│   ├── __init__.py    # Package initialization
│   ├── app.py         # Flask application (for local development)
│   ├── cli.py         # Command-line interface entry point
│   ├── core.py        # Shared core functions
│   ├── api/
│   │   ├── __init__.py
│   │   └── index.py   # Vercel serverless function
│   └── templates/
│       └── index.html # Frontend interface
├── setup.py           # Package installation configuration
├── vercel.json        # Vercel configuration
├── requirements.txt   # Python dependencies
├── uploads/           # Temporary uploaded files (created automatically)
├── outputs/           # Generated files (created automatically)
└── README.md          # This file

Node.js Version

.
├── bin/
│   └── bpm4b.js       # CLI entry point
├── lib/
│   ├── core.js        # Core conversion functions
│   └── server.js      # Express web server
├── templates/
│   └── index.ejs      # Frontend template
├── api/
│   └── index.js       # Vercel serverless function
├── examples/          # Usage examples
├── test/              # Unit tests
├── package.json       # NPM package configuration
├── vercel.json        # Vercel configuration
├── uploads/           # Temporary uploaded files (created automatically)
├── outputs/           # Generated files (created automatically)
└── README_NODE.md     # Node.js specific documentation

Notes

• Maximum file size for uploads: 2GB
• SSE (Server-Sent Events) used for real-time progress updates
• Kokoro AI engine runs locally (no API keys or external costs)
• M4B output files can be large (typically 0.96-2GB per hour of audio depending on bitrate)
• Optimized for high-speed conversion on Windows/macOS/Linuxion:
• X (Twitter): @jdjchelp

License

MIT