Add Audio to Video
Add Audio to Video replaces or mixes the soundtrack of any video with music or sound from an audio file, another video, or a link from SoundCloud, Internet Archive, X, Bluesky, Twitch or Pinterest. Pick the exact part of the audio, drag it to where it should start, loop it to fill the video, and export an MP4 — all in your browser, no upload.
Drag & drop your file here
or browse files from your device
Max size limit: 500 MB per file
Specifications
Guide
Upload your video
Drop an MP4, MOV, WebM or MKV video onto the upload zone. It stays on your device.
Add the new audio
Upload an audio file or another video — the sound is extracted automatically — or paste a SoundCloud, Internet Archive, X, Bluesky, Twitch or Pinterest link.
Pick the part and place it
Drag the waveform handles to choose the section you want, then drag the orange block on the timeline to set where it starts. Choose Loop to fill or Play once.
Mix and export
Keep or remove the original sound, set both volumes, preview by playing the video, then click Create video and download the MP4.
Key features
Any audio source
Use an MP3, WAV, M4A, OGG or FLAC file, the soundtrack of another video, or a link from six supported platforms.
Waveform clip selector
See the audio as a waveform and drag handles to pick the exact part — the chorus, the intro, or a 10-second sting.
Drag-to-place timeline
Drag the audio block along your video's timeline to start the music at exactly the right moment.
Loop or play once
Short track? Loop it seamlessly to the end of the video, or let it play once and finish in silence or the original sound.
Keep or replace original sound
Remove the original audio completely, or keep it underneath the new track with its own volume slider.
Live preview, lossless video
Hear the result by playing the video before exporting. The video stream is copied, never re-compressed.
Frequently asked questions
No. Your video never leaves your device — the soundtrack is mixed by FFmpeg.wasm inside your browser tab. Only when you paste a link is that public audio fetched through our relay, which stores nothing.
Choose Loop to fill and the selected part repeats seamlessly until the video ends, or Play once and it plays a single time. The timeline shows exactly where each repeat lands.
It is cut off when the video ends. Use the fade-out option for a smooth ending instead of an abrupt stop.
Yes. Choose Keep & mix under Original sound, then lower the New audio slider (30–50% works well for background music) so speech stays clear.
No. The video stream is copied bit-for-bit into the new MP4. Only the audio is newly encoded (AAC, 192 kbps).
MP4, MOV, WebM and MKV are supported, up to 500 MB. The result is always an MP4 that plays everywhere.
Learn more
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