Shrink Your MOV Files: Quick Video Compression with FFmpeg on macOS

Apple’s cameras (and even Screen Recording) capture gorgeous footage—but those pristine .mov files balloon in size. Luckily, a simple command with FFmpeg can trim them down without visible quality loss.

Install Homebrew (if not already installed)

Check out my How to Install Homebrew on macOS post for detailed instructions on how to install Homebrew.

1. Install FFmpeg via Homebrew

brew install ffmpeg

2. Simplest command

ffmpeg -i input.mov output.mp4

Here the input is the video you want to compress and the output is the compressed video.

3. Basic “good-enough” compression

ffmpeg -i input.mov -vcodec libx264 -crf 23 -preset medium -acodec aac -movflags +faststart output.mp4

Flag	What it does	Tweak if…
libx264	Encodes video with H.264 (plays everywhere)	Try libx265 for ~40% smaller files (requires newer devices)
-crf 23	Quality vs. size knob (0-51)	Drop to 20 for higher quality, raise to 28 for smaller files
-preset medium	Encoding speed vs. efficiency	slow compresses more, ultrafast is much faster
-movflags +faststart	Puts metadata up front so videos stream immediately	Always useful for web uploads

Expect 50-70% smaller files with the default settings.

Tip: Need to downscale 4K? Append -vf scale=-2:1080 to preserve aspect ratio while capping height at 1080 px.

4. Verify the results

ls -lh input.mov output.mp4

Check the file size difference to confirm compression worked.

5. Going further

You can also create a bash shortcut to compress videos:

function compress-video() {
  local input="$1"
  local output="${input%.mov}-output.mp4"
  ffmpeg -i "$input" -vcodec libx264 -crf 23 -preset medium -acodec aac -movflags +faststart "$output"
}

In your terminal, you can now compress videos by running:

compress-video input.mov

That’s it! You now have a lightweight workflow to shrink Apple-generated videos while keeping high-quality results.