Replace audio in video
Drop a video and a new soundtrack, and get the same picture with the new sound — video quality untouched.
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Replacing the audio in a video swaps the file's existing sound for a track you supply, while the picture stays byte-for-byte the same. The tool passes your video stream straight through and encodes only the new audio, which is why doing it this way — rather than rebuilding the clip in an editor — is fast and never softens the image. Suno creators reach for it when the visuals are already finished and only the song still needs to land on top.
Music and video usually come from different places: a Suno export here, a downloaded loop or an exported visualizer there, so you end up needing to marry a finished track to footage that carries the wrong sound or none at all. Because everything runs in your browser with ffmpeg.wasm, the video and your unreleased track never upload anywhere. The result is a standard MP4 you can post straight to YouTube, TikTok, or Instagram.
How it works
- 1
Drop the video file.
- 2
Drop the new audio track.
- 3
Click replace and download — the output ends with the shorter of the two.
When to use it
- Dropping a mastered Suno song onto a looping cover-art or visualizer clip for a YouTube music upload, so the video carries your final mix instead of a scratch bounce.
- Swapping the placeholder or auto-added audio in a downloaded stock/B-roll clip for your own track before posting a Reel or TikTok, so you're not publishing over someone else's Content ID'd music.
- Giving a silent screen-recording or photo slideshow (like a phone screen-capture with no mic sound) a soundtrack before it goes out on social.
FAQ
Is the video re-encoded?
No — only the audio is encoded; the video stream is copied, so there's no quality loss and it's fast.
What if the audio is longer than the video?
The output stops at the shorter input. Trim your audio first (or loop the video) if the lengths need to match.
Does the new track mix with the original audio, or fully replace it?
It fully replaces it. Only your new track is mapped into the output, so the video's original sound is dropped rather than layered underneath — there's no ducking or blending. If you want to keep both, combine them in an audio editor first, then drop that single mixed track in here.
What quality is the replacement audio saved at?
The new audio is encoded to AAC at 192 kbps, which is effectively transparent for music at normal listening levels. If you feed it a lossless WAV master it gets re-compressed to that AAC, so keep your original file — the output is a delivery copy for posting, not a master to archive.
What files can I drop in, and what comes out?
Drop a common video (MP4 or MOV) plus an MP3 or WAV for the new sound, and you always get an MP4 back. Since the video stream is copied instead of converted, the source needs an MP4-compatible video codec like H.264 — a WebM/VP9 clip may not copy cleanly into the MP4 container.
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