If a video plays in macOS's built-in QuickTime Player, it plays in this app. For unsupported codecs and the full list of file extensions, see Supported formats on the product page.
Start playback from Terminal, Shortcuts, or another app by passing files in a URL.
videogridplayer://play?file=<absolute path>[&file=<absolute path>...]
open "videogridplayer://play?file=/Users/you/Movies/a.mp4&file=/Users/you/Movies/b.mp4"
Put a URL in this form into a "URL" action and connect it to an "Open URLs" action.
/. Percent-encode spaces and similar characters (%20)