Not YouTube but regarding the period signifier:

Wes Anderson's "The Grand Budapest Hotel" has every section of the movie shot in the time appropriate aspect ratio.

But the presentation format is actually 1.85:1 so the 1930s part is pillarboxed slightly and the 1960s part is heavily letterboxed.

If you buy the Blu-ray it's presented in 16:9 and 1920x1080 throughout, it's just masked to suit.