Video & Audio
Add Audio to Video
Put a voiceover or your own music onto a video, in place of its sound. No upload, no signup.
Files stay on your device How it works
Drop files here, paste, or
MP4, MOV, WebM, MKV, MP3, M4A, AAC, WAV, OGG or FLAC · up to 2 files, 25 MB each
Your files
Your file is ready
How to add audio to a video
Add a voiceover to a screen recording, or give a slideshow video your own music in place of the sound it has. The sound starts with the video, so cut it first with Trim Audio if it should begin somewhere else.
- Choose one video (MP4, M4V, MOV, WebM or MKV) and one sound file (MP3, M4A, AAC, WAV, OGG, FLAC or WebM), in either order, each up to 25 MB and 30 minutes long.
- Tick Repeat if the sound is shorter than the video and should play again until the end.
- Press Add the sound and download the result: holiday-clip.mp4 becomes holiday-clip-with-sound.mp4.
What it does
- The sound is replaced: the new sound takes the place of the video’s own sound. The two aren’t mixed.
- The picture is copied, not re-encoded, so it’s exactly as it was, and the video keeps its format; an M4V comes out as an MP4.
- The sound is copied when the video’s format can hold it as it is, such as AAC from an M4A in an MP4, or Opus in a WebM, and it needn’t repeat. Otherwise it’s re-encoded to suit the video: AAC in MP4 and MOV, Opus in WebM and MKV.
- It fits the video: a longer sound is cut at the video’s end. A shorter one leaves the rest silent, unless Repeat is ticked. The note under the result says which.
Use sound you have the right to use
Your own voiceover, music you made, or a track whose license lets you use it this way. Music from elsewhere is usually under copyright, so check its terms before you share the video. This tool comes with no sound: you bring your own.
Which browsers work
Copying needs nothing special, so AAC sound from an M4A onto an MP4 works in current Chrome, Edge, Firefox and Safari, even with HEVC (H.265) video from an iPhone. Re-encoding the sound needs a current Chrome, Edge or Firefox, or Safari 26 or later. Firefox can’t make AAC, so there an MP4 or MOV whose sound is re-encoded gets Opus sound, which browsers and VLC play.
Good to know
Your files stay on your device; nothing is uploaded. The sound has to come from a sound file: to use another video’s sound, save it first with MP4 to M4A. This tool puts a new sound in place of the old one; to remove the sound and leave the video silent, use Mute Video.