Replace Audio in Video
Swap only the audio — video quality stays untouched.
Your files are never uploaded — everything runs right on your computer.Your files are never uploaded — everything runs right on your device.
How to use (3 steps)
- 1Pick a video fileDrop or click to select MP4 / MOV / MKV / WebM
- 2Pick an audio fileAAC / M4A / MP3 / WAV / FLAC — audio from video files works too
- 3Run and downloadPreview the result and save it
What this tool lets you do
It replaces only the audio track of a video while leaving the video stream untouched — for swapping background music, re-recording narration, or replacing commentary. Everything runs inside your browser, so your files stay safe on your device.
Tips for getting more out of it
Use the audio of another video directly
Drop a video file into the audio slot and its audio track will be used for the replacement — no need to extract the audio first.
The output format follows your input
MKV videos stay MKV, WebM videos stay WebM, and so on — the default is whichever format loses no information. You can switch between MP4 / MOV / MKV / WebM in the options (only formats that can store your video codec are listed).
Multi-GB files are supported
When the combined input size exceeds 2 GB, supported browsers (Chrome/Edge) open a save dialog before processing and stream the result directly to disk instead of memory.
FAQ
What does "full quality" mean?
The video data is never decoded or re-compressed — it is copied bit-for-bit into a new file (remuxing). Quality loss is impossible by construction, and processing is fast. AAC audio is stored as-is; other audio is converted to AAC, while the video still stays untouched.
What happens when the video and audio have different lengths?
The output always matches the video length: longer audio is trimmed, and shorter audio is followed by silence.
Does it work on mobile?
Yes, though very large files may fail due to memory limits. For multi-GB files we recommend Chrome/Edge on desktop.