Will DO11 support MP4 video metadata?

Under Preferences / Viewer / Viewer Plugins, the Movie viewer plugin needs to be enabled, and should also have the relevant extensions in the list you see if you click its Configure button.

If that is set up but you still don't see data for MP4 files in the Duration column, you may have a video codec/splitter or registry problem.

Note that different columns are supported for different formats, but the Duration one definitely works for MP4 files here. (Also, I'm talking about columns in the file display. The metadata panel is separate and will only show things Opus knows how to edit, so it won't show much for MP4 files at the moment.)