Television as an invention was in development for quite a long time. Broadcasting was done on a limited basis. From my understanding, manufacturers were asked to defer the introduction of television to the general public during World War II so that the technical resources could be diverted for war production.
This 1938 article in Life is illustrated with still photos taken of a Broadway play from a TV screen. This particular play, Susan and God, from its description, was done as something of a test, from the RCA Studios to televisions within the building, but the photos were taken in the offices of Electronics magazine, where an amateur receiver was used to catch the broadcast signals.
The YouTube video is from a 1941 theatrical short, explaining how TV works. (In the modern day world of YouTube, copyrights and other considerations, if you see a black screen it’s because YouTube pulled the video for their own reasons. Sorry. Who knows...maybe someday you can see in on television!)