https://aescripts.com/jpeg-glitch/
We broke the JPEG algorithm to make realistic glitches in After Effects.

• JPEG glitch plugin uses JPEG compression algorithm to create effects. You can add some “errors” in each step of the algorithm or change values manually. This manipulation creates special glitch aesthetics, which is possible only with JPEG compression algorithm. We broke JPEG for you in a very controlled way and we give you a control panel.Technically, the plugin receives each frame as a separate picture, converts it to a JPEG, and returns it in the same picture format. In the conversion stage, all magic happens, where all “errors” and glitches are added. We made it so that all “errors” and broken bytes are left at the conversion stage, so the plugin returns only “healthy” pictures, so you don’t have to worry that your rendered file will not work.