Replace Video Audio Track
Swap a video's soundtrack for a different audio file — new music, dubbing, cleaner sound
The output uses your video's picture and the new audio's sound. If the two are different lengths, the result is trimmed to whichever is shorter.
⚠️ Please don't close or refresh this page until it's done, or you may lose the result.
💡 Large files travel at your connection's pace: the upload continues on its own and resumes safely, so a slow link only affects time, never your credits.
How it works
- 1
Upload your video and the new audio file.
- 2
Click swap — the server combines them into one MP4.
- 3
Preview and download the result. Files auto-delete in 30 minutes.
Swap soundtracks without touching video quality
The video stream passes through untouched — only audio changes — so there's zero generation loss on the picture.
Picture Copied Untouched
When the format allows, the video stream is copied without re-encoding, so the picture keeps its original quality and the job takes far less time than a full conversion.
New Track, AAC Audio
The replacement file is encoded as AAC and muxed with your footage — background music, a voiceover or a cleaner recording all fit the same workflow.
Auto-Trims to Shortest
The output is trimmed to whichever input is shorter, so a longer soundtrack never leaves dead audio hanging past the final frame.
Sync and mixing controls
- Stream copy — video bits pass identical; duration adapts to the longer or shorter track per your choice.
- Offset trim — nudge new audio by fractions of a second to land on lip movement.
- Duck mix mode — keep original audio at reduced volume under music instead of full replacement, with fade points you set.
Frequently asked questions
What happens if the video and audio are different lengths?
The result is trimmed to whichever is shorter, so there's never a silent tail or a frozen frame with sound still playing. Trim either file to the length you want beforehand if you need exact control.
Will the video quality drop?
No — for MP4-compatible codecs the picture is stream-copied untouched (identical to the original, instant). Only the audio is re-encoded, to AAC at a solid bitrate.
What happens to my files?
Both uploads and the result are deleted automatically within 30 minutes. Only your session's signed token can access the job.
Related tools
What Does Replacing Video Audio Mean?
Replacing video audio means swapping a video original soundtrack for a different audio file — new background music, a voiceover, or cleaner sound. This tool does it on our VPS: you upload your video and the new audio, and get back a video with the same picture and the new soundtrack. When possible, the video stream is copied untouched, so there is zero quality loss; the new audio is encoded as AAC, and the output is trimmed to whichever of the two inputs is shorter. The original picture is preserved untouched where possible, so the result looks exactly like your source footage — whether you are adding music or re-dubbing the whole thing.
What this tool can do
- 🎵 Upload your video and the replacement audio file
- 🎬 The picture is copied untouched whenever possible — zero quality loss
- 🔊 The new audio is encoded to AAC for broad compatibility
- ⏱️ The output is trimmed to the shorter of the two inputs
- 🎞️ Any video input format works
- 🗑️ Both uploads are auto-deleted within 30 minutes
When you would use it
- You want background music under a video that had none
- You are dubbing a video with new narration
- The original recording is poor and you have a better take
- You want to swap a copyrighted soundtrack for something else
Your video and audio are uploaded to our VPS, combined with FFmpeg and auto-deleted within 30 minutes; the job consumes credits based on duration. Two practical notes: the output length equals the shorter input — if your audio is longer than the video it is cut at the video end, and vice versa — and the new audio is always re-encoded to AAC for maximum compatibility.
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