Depends on the shoot, some can take 20 minutes or so, the one above had about 70 frames and then an hour or so editing, sometimes adding text and usually music too.
I made one a while back using a track by Deliah Derbyshire (the one who wrote and produced the Doctor Who theme music) thinking it was 60 years old and out of copyright. When I tried to upload it to Youtube the A.I. said the music was copyright of the bbc from the 1980's
Now what is a "public broadcaster" doing spending licence payers money on copyrighting someone else's music from the 1960's?