Free browser tool
Add Audio to a Video
Put a voiceover or music file onto a silent screen recording. Drop the video and the audio, then download an MP4. Nothing is uploaded.
Video
MP4, MOV, MKV, WebM
Audio
MP3, M4A, WAV, or another video
Both files stay on this device. Nothing is uploaded.
Sponsored by the makers
Tired of boring screen recordings?
Try Screen Charm.
Auto-zoom, captions, motion blur, camera overlay and a vertical layout for Shorts. Record once, export a polished video.
Screen Charm is a native macOS app.
How to add audio to a video
Add the video
MP4, MOV, MKV, AVI, or WebM. A silent screen recording is the usual case.
Add the sound
MP3, M4A, WAV, or another video. Only the audio track from that file is used.
Download the MP4
Play it on the page, then download. The new track replaces whatever sound was already there.
Frequently Asked Questions
How do I add audio to a silent screen recording?
Drop the video in the first box and the voiceover or music file in the second. Click Add audio. The download is an MP4 with the new sound. The old audio track, if there was one, is replaced.
Will this re-encode my video?
The picture is copied when the source can live in an MP4. If it cannot, the video is re-encoded. The new audio is always saved as AAC.
What if my voiceover is shorter than the video?
The full video is kept and the sound stops when the audio file ends. Turn on “End when the shorter file ends” if you want the video cut to the audio length.
Is the file uploaded?
No. FFmpeg runs in your browser. The video and the audio stay on your device.
Related guides
More Free Tools
Sponsored by the makers
Tired of boring screen recordings?
Try Screen Charm.
Auto-zoom, captions, motion blur, camera overlay and a vertical layout for Shorts. Record once, export a polished video.
Screen Charm is a native macOS app.