Run FFmpeg in Browser with WebAssembly (ffmpeg.wasm)

Run FFmpeg in Browser with WebAssembly (ffmpeg.wasm)

A practical guide to running FFmpeg in browser using WebAssembly, including use cases, limits, and performance tips.

Run FFmpeg in Browser with WebAssembly

Running FFmpeg in browser is possible with ffmpeg.wasm. This lets you execute FFmpeg commands online without local installation.

Why people use browser FFmpeg

  • No install required.
  • Works on locked-down school/work devices.
  • Fast setup for quick media tasks.
  • Private local processing in the browser runtime.

Practical examples

  • Resize a video: ffmpeg -i input0.mp4 -vf scale=1280:-2 output.mp4
  • Trim a clip: ffmpeg -i input0.mp4 -ss 00:00:03 -to 00:00:10 -c copy output.mp4
  • Compress output size: ffmpeg -i input0.mp4 -crf 28 -preset veryfast output.mp4

Browser-based FFmpeg limits

  • Browser memory limits can affect very large files.
  • Processing speed depends on device hardware.
  • Long, complex pipelines are usually better with native local FFmpeg.

If you need heavy batch processing, keep a local FFmpeg setup. For quick command execution, browser FFmpeg is usually faster to start.