Checking US copyright renewal

Many movies and series have already fallen into the public domain. Because of differences in copyright law throughout time and jurisdictions, it's not a straightforward answer on how to determine public domain status. For movies first released in the US between 1930 and 1963, we need to check if a movie was copyrighted to begin with, and then if the copyright was registered to be renewed. Using a Betty Boop episode as an example, I show how I check copyright renewal.