Video Resizer — Change Resolution & Aspect Ratio

Video Resizer changes the pixel dimensions of a video — a 4K clip written back at 1080p or 720p, or at any width and height you name.

Scaling is done by ffmpeg's scale filter, with presets from 2160p down to 360p that fix the height and let the width follow. With the aspect lock on you supply one dimension and the other is computed to the nearest even number, so the picture is never stretched; switch the lock off, give both, and it will be. What this page cannot do is pad: there is no way to put a 16:9 clip inside a 9:16 frame with bars above and below, so making something vertical means cropping it instead. The finished file is probed after encoding, so the dimensions reported back are the ones actually in it rather than the ones requested.

Scaling and re-encoding both happen in the page, so unreleased footage can be prepared for review without a copy of it coming to rest on anyone else's disk.

Cutting 4K camera files down to something a website can serve, matching a platform's maximum upload resolution, shrinking a screen recording made on a retina display, and making a light proxy of a heavy clip.

Also known as: change video resolution · resize video dimensions · scale video · downscale 4k to 1080p · video aspect ratio converter · reduce video dimensions