I found the text accompanying the youtube submission quite helpful to understand the simulation:
The intensity movies show the star approximately as it might appear to the human eye (In detail: The emergent bolometric surface intensity is color coded with the standard "red-heat" table, to get a color representation adequate for a red supergiant.). The "boiling" surface of the star shows irregular hot (white or yellow) and "cool" (red or dark-red) areas. They change their intensity and shape on time-scales of months.
Very fascinating.
I found the text accompanying the youtube submission quite helpful to understand the simulation:
Edit: typo