Add Music to Video
Replace a video's audio with a song or voiceover you upload — in your browser.
Select the video
MP4, MOV, WebM
Click to choose, or drop a file here
Select the music / audio
MP3, WAV, M4A — replaces the video's sound
Click to choose, or drop a file here
About adding music to a video
Adding a song or a voiceover to a clip — background music for a montage, narration over a demo, a track under a slideshow — normally means opening a video editor. This tool does the common case in your browser: it replaces a video's audio with an audio file you upload.
It plays the video muted onto a canvas while playing your audio track through the recorder, and captures both together into one MP4 or WebM. The video's own sound is dropped entirely — this is a replace, not a mix. Audio longer than the video is cut to length; audio shorter than the video leaves silence at the end.
Like the other re-recording tools here it runs in real time (the video's length) and re-encodes once, so it suits short clips. To keep some of the original sound alongside the new track, mix them together in an audio editor first, then add the combined track here.
Supported files
Accepts a video (MP4, MOV, WebM) plus an audio file (MP3, WAV, M4A). Produces an MP4 or WebM.
Is my file uploaded?
No. The video and audio are combined entirely in your browser — neither file is uploaded.
Common problems
- I wanted to keep the original sound too
- This replaces the audio. Mix the original and the new track in an audio editor, then add that combined file.
- The music cuts off early
- The audio is trimmed to the video's length. Trim the video longer, or pick a shorter section of the song.
How to Add Music to Video
- 1
Add the video
Drop in the clip.
- 2
Add the audio
Drop in a song or voiceover — it replaces the video's own sound.
- 3
Combine and download
Click Add music; the video plays with the new track and is re-recorded.
Related PDF tools
Add Music to Video — frequently asked questions
Is anything uploaded?+
No. The video and the audio are combined entirely in your browser.
Does it keep the original sound?+
No — the uploaded track replaces the video's audio. To keep both, mix them in an audio editor first.
What if the song is longer than the video?+
It's cut to the video's length. A shorter song leaves silence at the end.
Does it re-encode?+
Yes, in real time (the video's length). Best for short clips.
Do you upload my files to a server?+
No — every tool here processes your files entirely on your device, and nothing is uploaded to a server. The only exception is the AI tools, which send the extracted text (not the file) to Claude to do their work.
Is there a file size limit?+
There's no artificial limit we impose, but since processing happens in your browser, very large files (500+ MB or 1,000+ pages) are limited by your device's memory rather than by us.
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