Resize MP4 files

Resizing is usually the biggest lever for reducing MP4 file size.

Last updated: 2026-03-18

To resize MP4 files, run npx optimo video.mp4 --resize <value>. Optimo supports three modes: percentage (50%), dimensions (w960), and target file size (150kB). Resizing reduces both dimensions and file size in one step — often more effective than compression alone.

Resize by percentage

Quick way to scale down when you don't know exact dimensions yet.

npx optimo video.mp4 --resize 50%

Resize by dimensions

Cap width or height to match how the asset is displayed.

npx optimo video.mp4 --resize w960

Use w for width and h for height.

Resize to a target file size

Useful for thumbnails and previews when you want predictable budgets.

npx optimo video.mp4 --resize 150kB

Start with a budget you can ship everywhere, then adjust based on quality.

MP4-specific tips

  • Match the video width to the player size; oversizing wastes bandwidth.
  • Shorten duration when possible; seconds matter more than codec tweaks.
  • For background loops, consider converting to WebM and compare sizes.

Frequently asked questions

How do I resize MP4 files?
Optimo supports three resize modes: percentage (--resize 50%), dimensions (--resize w960 or --resize h480), and target file size (--resize 150kB). Run "npx optimo video.mp4 --resize <value>" to resize and optimize in one step.
What is the best resize mode for MP4?
Use dimensions (--resize w960) when you know the display size. Use percentage (--resize 50%) for quick scaling. Use target file size (--resize 150kB) for thumbnails and budgets. Resizing is usually the single biggest lever for reducing MP4 file size.