🎵 Add Audio to Video
Put background music under a clip, swap in a clean voiceover, or mix both — the video stream is copied without re-encoding.
✅ Free · No sign-up
Choose a video or drag it here
Processed on your device — nothing is uploaded
Processed on your device — nothing is uploaded
Choose an audio file or drag it here
MP3, WAV, M4A, OGG…
MP3, WAV, M4A, OGG…
Length
Result
How to use the Add Audio to Video
- Choose the video and the audio file.
- Pick mix or replace, the start offset, volumes and fades.
- Press Create video, check sync in the preview and download.
Why creators use it
- Add licensed background music to a Reel or Short.
- Replace a noisy on-camera track with a cleaner recording.
Good to know
- Uses FFmpeg compiled to WebAssembly (about 30 MB, downloaded once from jsDelivr and cached). It runs on one CPU core, so long or high-resolution videos take a while.
- The video stream is copied (no quality loss); audio is encoded to AAC, and the output is MP4. Source videos in WebM/VP9 are re-muxed into MP4 if compatible, otherwise re-encoded.
- The output always matches the video’s length. Check sync in the preview — sources with variable frame rate can drift slightly.
- Use music you have the rights to; platforms detect copyrighted tracks.
Frequently asked questions
Will the video lose quality?
No. When possible the video stream is copied byte-for-byte; only the audio is re-encoded.