Add Music to Video
Add Music to Video lays a soundtrack over your clip. Replace the original audio entirely, or mix the music underneath it, and set the music volume to taste. The track is trimmed to the length of the video automatically. It all happens in your browser — neither your video nor your music is uploaded.
Add your video
The file is read by your browser and stays on your device — there is no upload step.
Your video
The work runs in this tab. Nothing is sent anywhere, and the download is generated locally.
How to use Add Music to Video
- 01Upload
Add your video
Drop a clip in, then choose a music file — MP3, WAV, M4A and more are supported.
- 02Customize
Choose replace or mix
Replace swaps the soundtrack entirely; Mix lays the music over the original audio. Set the music volume with the slider.
- 03Process
Export
Export to combine the video and music into one file and download it.
What you are adding
The music is mixed with whatever sound the clip already has, or replaces it. Deciding which of those you want is the first choice to make.
The export contains one combined audio track. The music and the original cannot be separated again afterwards.
Getting the balance right
- Under speech−18 to −25 dB
Music behind a voice needs to be much quieter than feels right while you are setting it. If you notice the music, it is too loud.
- No speech−6 to −12 dB
Music carrying the whole clip can sit far higher, but still leave headroom before maximum.
- Fade the ends
Music that starts and stops abruptly is the clearest sign of a rushed edit. A short fade at each end fixes it.
Before you publish it
Commercial music will be detected — Automated systems identify recordings within minutes of upload. Outcomes range from muting to takedown to the rights holder taking the revenue.
"Royalty-free" still has terms — It usually means no recurring fee, not no licence. Read what it permits, particularly for commercial use.
The platform library is the safe route — Music offered inside the platform you are posting to is pre-cleared for that platform, and nowhere else.
Supported formats
- MP4
- MOV
- WebM
- AVI
- MKV
- Maximum file size —
- bounded by your device's memory
- Processed by —
- FFmpeg (WebAssembly), on your device
Your file, and what the page does
Your file is never uploaded. Add Music to Video reads it into this browser tab and processes it with FFmpeg compiled to WebAssembly on your own device. There is no upload endpoint in the application and no copy on any server — closing the tab discards it.
That is also why processing takes longer here than on a site that uploads: your device is doing the work rather than a rack of servers. The trade is that the file never leaves it.
What the page does send or fetch
- The processing engine, once
- The first time you use any video or audio tool, the browser downloads the FFmpeg WebAssembly build (~30MB) from the jsDelivr CDN and reuses the cached copy afterwards. That is a file coming to you — no part of your own file is in the request.
- Ads on the page
- The site is funded by advertising, so the page loads Google AdSense. That carries the usual web basics — IP address, browser, referring page — as on any ad-supported site.
- An anonymous usage counter
- When Add Music to Video finishes we record that the tool ran, whether it succeeded and how long it took. No file data, no identifier, no cookie.
Your file is not on that list. How this works.
Frequently asked questions
Yes — choose Mix to blend the music over the video's existing audio. If the video is silent, the music simply becomes the soundtrack.
The music is trimmed to match the video's length, so the result ends when the video does.
Common formats including MP3, WAV, M4A/AAC and OGG all work as the music source.
Yes — Add Music to Video is completely free. There's no account, sign-up, watermark or limit.
No. It runs in any modern browser — Chrome, Edge, Safari, Firefox, Brave — with nothing to download or install.
Not sure this is what you need?
- Music under a videoAdd Music to Video
- Remove the existing sound firstMute Video
- The music is too loud or quietAdjust Volume
- Stills set to musicSlideshow Maker
Edit any media with a right-click
Add Dexta Studio to Chrome and open any image, video, audio or PDF straight into the right tool — free, nothing uploaded.