A lightning-fast, client-side web app to automatically mix podcast vocals with background music. Features smart audio ducking, fade in/out, waveform preview, and local MP3/WAV export. 100% private, runs entirely in your browser with zero server uploads!
- 100% Privacy-First: Everything happens locally in your browser. Audio files are never uploaded to a server, ensuring your content remains completely private.
- Smart Audio Ducking: Automatically lowers the background music volume exactly when your voice track starts, and raises it back up when you finish speaking.
- Advanced Automations: Customize fade-ins, fade-outs, ducking anticipation time, and volume transition smoothness with millimeter precision.
- Interactive Waveform Player: Preview your generated mix instantly. Click on the visual audio wave to navigate through the track, or use the custom playback speed controls (0.5x to 2.0x).
- Multi-Format Export: Download your final masterpiece in high-quality
.mp3, pristine.wav, or compatibility-friendly.oggformat. - Drag & Drop Interface: Intuitive and smooth file management for both Voice and Background tracks. Includes a fully responsive, adaptive Dark/Light mode UI.
- Drag and drop your podcast voice file and your background music into the dropzones.
- Tweak your mixer settings (Fade durations, Ducking volume, Playback Speeds).
- Click "Generate Mix". The app uses the browser's native
OfflineAudioContextto render the audio at maximum CPU speed, completely bypassing real-time playback. - It calculates the exact mathematical timings to center your voice track over the music, utilizing
GainNodeautomations to sculpt the volume curves. - The app generates a temporary local
Bloband renders an interactive waveform using WaveSurfer.js. - Listen to the preview and click download to instantly save the file via the built-in LameJS encoder!
- Serverless Audio Processing: Performing complex audio mixing, ducking, and MP3 encoding entirely on the front-end is incredibly rare. It completely replaces the need for heavy backend tools like FFmpeg.
- Instant Offline Access: Once the local libraries are set up, you can literally save the folder on your desktop, disconnect your Wi-Fi, and use it offline forever.
- Podcasters & YouTubers: Quickly add intro/outro music and background beds to your vocal tracks without having to open heavy DAWs (Digital Audio Workstations) like Audacity, Premiere, or Logic.
- Content Creators: Merge voiceovers with soundtracks in seconds with professional-sounding volume transitions, saving hours of manual keyframing.
Simply visit the Live Demo hosted on GitHub Pages.
Running this tool locally without internet is extremely easy:
- Clone this repository or download the source code ZIP.
- Ensure the
libs/folder is present (it contains the local copies of Tailwind, WaveSurfer, LameJS, and FontAwesome). - Double-click
index.htmlto open it in your favorite browser. - Start mixing!
