Merge Video and Audio
Add or replace audio in a video file online. Merge any video with any audio track. No upload needed.
About this tool
Add or replace audio in a video file online. Merge any video with any audio track. No upload needed. This tool runs entirely in your browser — no file upload, no account required, and no data is ever sent to a server. Video conversion is powered by FFmpeg compiled to WebAssembly, running entirely inside your browser tab.
- ✅ Free to use, no sign-up required
- ✅ Files never leave your device
- ✅ Powered by WebAssembly — no plugins needed
- ✅ Works on any browser and device
How it works
FFmpeg (compiled to WebAssembly) handles the video transcoding entirely in your browser. Your video is decoded from the source format and re-encoded into the target format. Depending on file size, processing may take a moment.
Frequently Asked Questions
Is Merge Video and Audio free to use?
Yes, Merge Video and Audio is completely free. There are no usage limits, no sign-up required, and no hidden fees.
Are my files safe when using this tool?
Completely. All processing happens locally in your browser using JavaScript and WebAssembly. Your files are never uploaded to any server and never leave your device.
Does Merge Video and Audio work on mobile?
Yes, Merge Video and Audio works in any modern browser including mobile browsers on iOS and Android — no app installation required.
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