Add Audio to Video
Put your own music or voice-over onto a video — replace the original sound or mix them together.
Everything ran in your browser — nothing was uploaded.
How to use the Add Audio to Video
- Drop in a video.
- Choose your audio file and how it should fit.
- Click Process and download the video with its new sound.
About the Add Audio to Video
Add Audio to Video puts a new soundtrack onto a clip. Pick a video, choose an audio file — music, a voice-over, a podcast bed — and the tool muxes it in, either replacing the original sound completely or mixing your track over it. The picture is copied without re-encoding, so it stays sharp and the export is quick. All processing happens in your browser with ffmpeg (WebAssembly), so your files are never uploaded — it is private and free with no watermark.
You control how the two lengths meet: keep the video length (extra audio is trimmed, short audio leaves the tail silent) or stop when either one ends. You can lift or drop the new track's volume, and tick “keep the original audio” to blend rather than replace. It works best on short clips, since the work runs on your device rather than a server.
Frequently asked questions
Is my video uploaded?
No. Everything runs in your browser with WebAssembly; nothing is uploaded.
Does it remove the original sound?
By default yes — your audio replaces it. Tick “keep the original audio” to mix your track over the existing sound instead.
What audio formats can I use?
Common ones like MP3, WAV, M4A, AAC and OGG all work. The output audio is encoded as MP3 inside an MP4.
What if the audio is longer or shorter than the video?
Choose “Match the video length” to keep the video duration (extra audio is cut, short audio leaves silence at the end), or “Stop when either ends”.