Replace Audio in Video
Replace the audio track of a video with your own
Drop a video file (MP4, WebM, MOV, AVI, MKV)
🔒 Files never leave your device
Drop an audio file
🔒 Files never leave your device
Output length matches the shorter of the two.
⚡ Uses FFmpeg WebAssembly. First run downloads ~30 MB (cached after). Encoding takes roughly 1–5× the video's duration.
How it works
- 1Upload your video
Drop or select a video file.
- 2Configure options
Choose the settings that fit your use case.
- 3Download
Save the processed video to your device.
About Replace Audio in Video
Replace Audio in Video — free online tool that runs entirely in your browser via FFmpeg WebAssembly. Your video never leaves your device. Replace Audio in Video on DashConvert runs entirely inside your browser using modern JavaScript APIs — no server ever sees your files. That means faster conversions, complete privacy, and no upload limits.
Whether you need to replace the audio track of a video with your own for work, study, or personal use, this tool is free to use as many times as you need. There are no watermarks, no sign-up, and no ads inside your documents.
Frequently asked questions
Are my videos uploaded?
Never. Processing runs entirely in your browser using FFmpeg WebAssembly.
Why is it slow?
Video encoding is CPU-heavy. Expect roughly 1–5× the video's duration for encoding. First-time load also downloads ~30 MB of FFmpeg (cached after).
What's the file size limit?
Depends on your device's memory. Files up to ~1 GB usually work; multi-GB files may crash the tab.