Betelgeuze in Orion loses her light

Betelgeuze: When we see the film of an animation of losing light of betelgeuze on You Tube, we see a picture of Betelgeuze with a very bad quality, and that for an organization with high quality equipment.
When we take a picture with a compact camera with telephoto lens, we have a much better quality.

Questions:
What is the reason that Betelgeuze loses her light?
And what do you think about the animation on You Tube?
https://www.youtube.com/watch?v=o1ls7Gr9LTE