Browser FFmpeg recipe

Compress MP4 Online with FFmpeg

Create a smaller MP4 with more aggressive compression.

Command

Run this FFmpeg command

ffmpeg -i input.mp4 -c:v libx264 -crf 29 -preset fast -c:a aac -b:a 96k compressed-mp4.mp4

When to use it

  • large MP4 files
  • email uploads
  • storage cleanup

How it works

  1. Upload the MP4 file.
  2. Adjust CRF if you need higher quality or smaller size.
  3. Run FFmpeg and download the compressed MP4.

Option reference

OptionWhat it does
-crf 29Uses stronger H.264 compression.
-preset fastKeeps encoding practical in the browser.
-b:a 96kUses compact AAC audio.

Practical notes

  • Use CRF 23 to 26 for higher visual quality.
  • Combine compression with resize if the file is still too large.

FAQ

Is this different from compress video?

This recipe is tuned specifically for MP4 input and a smaller AAC audio bitrate.

Can I preview the output size first?

No, run the command and compare the downloaded file size.