Video converter · runs 100% in your browser
MP4 to AVI Converter
Convert MP4 video to AVI in your browser. MP4 is most universally compatible container, H.264/AAC by default; AVI is older Microsoft container, broad legacy support, weaker streaming. The re-encoding runs through a WebAssembly FFmpeg build — no cloud render farm, no upload bar, no privacy worries.
How to use
- Drop your MP4 video onto the page.
- FFmpeg.wasm boots locally on first use — give it a moment, it caches for the rest of your session.
- Re-encoding to AVI happens entirely in your browser; your video never uploads.
- Download the AVI file when conversion finishes — large videos take a few minutes.
FAQ
Why is the first MP4 to AVI conversion slow to start?
The first audio or video conversion of your session downloads the FFmpeg.wasm runtime (~25 MB). Subsequent conversions skip that step. After it loads, MP4 → AVI re-encoding starts immediately.
Does the converter re-encode or just remux?
It re-encodes both video and audio so that the resulting AVI file is widely compatible. Pure remuxing is a future option but is not yet exposed in the UI.
What codec does the AVI output use?
MPEG-4 video and MP3 audio for broad compatibility. Quality and bitrate are tuned for a sensible default.
Does video really not upload?
Correct. The conversion runs locally via FFmpeg.wasm. You can verify in DevTools: no outbound traffic carrying your file.