Autocompressor

Autocompressor is a hosted compression service by Auto-Rez Media Technologies. You upload a file, or paste a link to a video page or file, pick a target size, and it re-encodes the media to fit: videos stay videos, images stay images, animations stay animations. It is meant for people who need something under a size limit quickly, typically for chat apps, and do not want to work out bitrates themselves. According to its About page, it chooses resolution and bitrate automatically and uses FFmpeg, ImageMagick, Gifsicle, MozJPEG and ECT behind the scenes.

How to use it:

1. Upload a file (up to 2 GiB) or paste a URL. Links are fetched with yt-dlp; videos longer than an hour are rejected.
2. Pick a target size: presets from 1 to 500 MiB, plus Discord emote and sticker modes. Custom sizes need a paid plan.
3. Pick a format family. MP4 is the most compatible; WebM (including AV1 in WebM) embeds in Discord; the AV1 MKV/AVIF and VVC/JPEG XL families are smaller but play in fewer places.
4. Pick an effort level from Fastest to Extreme; the two slowest require paid plans.

Finished files are deleted after 24 hours, so download the result rather than sharing the link. The service is closed source and its encoder settings are not published. If you need control over the settings, encode locally with FFmpeg; for Discord’s limits and supported formats see Discord.