How do I resize WebM 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.webm --resize " to resize and optimize in one step.

What is the best resize mode for WebM?

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 WebM file size.

Resize WebM files

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

Last updated: 2026-03-18

To resize WebM files, run npx optimo video.webm --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.webm --resize 50%

Resize by dimensions

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

npx optimo video.webm --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.webm --resize 150kB

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

WebM-specific tips

For product UI recordings, `--resize w1280` is often enough.
If quality looks soft, try a slightly higher resolution and compare file size.
Keep bitrate under control by avoiding unnecessary high FPS exports.

Optimize WebM Compress WebM WebM format guide

Frequently asked questions

How do I resize WebM 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.webm --resize <value>" to resize and optimize in one step.
What is the best resize mode for WebM?: 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 WebM file size.