Avidemux is a free open-source program designed for multi-purpose video editing and processing, which can be used on almost all known operating systems and computer platforms.
Unfortunately the user interface feels outdated and the latest version 2.8.1 has not been updated since September 2022.
The Avidemux menu at the top has a menu item labeled "Custom." I have not figured out what this menu item does. What is this menu item for?