How smaller.video works
The short version: FFmpeg runs inside your browser. Your video never leaves your device.
FFmpeg, compiled to WebAssembly
FFmpeg is the video processing engine behind YouTube, VLC, and most professional tools. It's a 20-year-old C codebase that handles virtually every codec and container ever invented. Compiled to WebAssembly, it runs directly in your browser tab at close to native speed.
When you compress a video on smaller.video, the entire FFmpeg binary (~30MB) runs locally. No data is sent to any server.
$ ffmpeg -i input.mp4 \
-c:v libx264 \
-crf 23 \
-preset fast \
-vf scale=-2:720 \
-c:a aac \
output.mp4
✓ Done. 68% size reduction.
The privacy guarantee
Your video bytes travel zero distance over the network. The file stays on your disk and in your browser memory only.
We have no user database. There is nothing to log in to, and therefore nothing to breach.
We do not collect analytics on what files you compress, their names, sizes, or contents.
Step by step
You select a video file
The browser reads the file from your disk into memory. Nothing is transmitted.
FFmpeg WASM loads
The ~30MB FFmpeg WebAssembly binary is downloaded (once, then cached). It initialises a virtual filesystem entirely inside your browser tab.
The file is written to the virtual FS
Your video is written to FFmpeg's in-memory virtual filesystem — a sandboxed environment that exists only in your browser tab.
FFmpeg compresses the video
The compression command runs. You can watch live progress from FFmpeg's output. It's the same FFmpeg binary that ships with VLC, running in your browser via WebAssembly.
Output is read back
The compressed file is read from the virtual FS, converted to a Blob URL in your browser, and offered as a download.
You download the result
Your compressed video is saved to your disk. The virtual FS is cleared. No trace remains anywhere on our end.