Add Audio to Video
Replace a video's sound or mix music on top of it
- Files never leave your device
- Runs in your browser
- Free, no sign-up, no watermark
Drop a file here, or click to choose
Accepts MP4, MOV, WebM, MKV · You can also paste with Ctrl+V / ⌘V
How to use Add Audio to Video
Put music or a voice-over on a video. Replace the original sound or mix the new audio over it, set where it starts and which part of the audio to use, and add fades. The picture is copied as is, so its quality does not change.
- 1
Drop the video, then drop the audio file. MP3, WAV, M4A, OGG, FLAC or another video's soundtrack all work.
- 2
Choose Replace or Mix, and set the Original sound and New audio volumes (0 to 200%).
- 3
Under Timing, set Starts at (in the video), turn Loop the audio or End with the audio on or off, and add Fade in and Fade out.
- 4
Drag the blue handles under Part of the audio to use, press play to preview, then click Add audio and Download.
Frequently asked questions
Is the video re-encoded?
No. The video stream is copied untouched; only the new audio track is encoded (AAC for MP4 and MOV, Opus for WebM and MKV). The output keeps the video's format.
What if the music is shorter than the video?
Loop the audio repeats the chosen part until the video ends, and is on by default when the audio is shorter. Or turn on End with the audio to cut the video where the music stops.
And if the music is longer?
It is cut where the video ends. Add a Fade out so it does not stop abruptly.
Can I use the sound from another video?
Yes. The second drop zone accepts video files and uses their audio track.
Does the preview match the saved file?
Yes. The player uses the same timing, volumes and fades that are written to the file.
Are my files uploaded?
No. Both files are processed in your browser and stay on your device.