Convert video and audio in your browser
No uploads, no queue, no sign-up. Every file is decoded and re-encoded on your own device, so nothing leaves your computer and there is no server-side size limit.
How it works
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Drop a file The browser reads it straight from your disk. Nothing is copied to a server.
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Pick an output Choose format, quality and — where it makes sense — a size or a time range.
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Save the result The new file is built in memory and downloaded directly. No queue, no waiting room.
Why run the conversion in the browser?
Most online converters upload your file to a server, process it there, and hand back a download link. That means your video sits on someone else's disk, the upload takes as long as your connection is slow, and there is always a file size cap.
MediaFuse does the work locally. Modern browsers ship WebCodecs, a hardware-accelerated media API, and the mediabunny library we build on top of it handles container parsing and muxing. The practical result:
| Concern | Server-based converter | MediaFuse |
|---|---|---|
| Where the file goes | Uploaded to a third-party server | Stays in your tab's memory |
| File size limit | Usually 100 MB – 2 GB | Bounded by your RAM, not by us |
| Upload time | Minutes on a slow connection | None — the file is already local |
| Works offline | No | Yes, after the first page load |
| Watermark | Often on free tiers | Never |
Supported formats
| Container | Read | Write |
|---|---|---|
| MP4 / MOV / M4A | Yes | Yes |
| WebM / MKV | Yes | Yes |
| MP3 / WAV / FLAC / OGG / AAC | Yes | Yes |
| TS (MPEG transport stream) | Yes | No |
| AVI / WMV / FLV | No — container not supported | No |
Video codecs: H.264, H.265/HEVC, VP8, VP9, AV1. Audio codecs: AAC, MP3, Opus, Vorbis, FLAC, PCM. What can actually be encoded depends on your browser and hardware — Chrome and Edge on desktop have the widest support.
Questions
Do I need to install anything?
No. The engine is a JavaScript bundle served with the page and cached by your browser. There is no extension, no desktop app and no account.
Which browsers are supported?
Chrome and Edge 94+, Safari 16.4+ and Firefox 130+ on desktop. Mobile Safari works for most formats; Android Chrome works for MP4 and WebM. Older browsers without WebCodecs cannot run the tools at all.
What happens if I close the tab mid-conversion?
The conversion stops and the in-memory result is discarded. Nothing partial is written to disk, and nothing was ever sent to a server.
Why is a 4 GB video slower here than on a server?
Server farms have dedicated encoders. A browser uses your own CPU and GPU, so a big file will take longer — but you also skip a multi-gigabyte upload, which is usually the slowest part.