Unless you happen to take notice during the film credits in movies where it is sung, you might not realize that filmmakers pay royalties to a unit of Time Warner for performances of Happy Birthday. But the credits are always there: Happy Birthday, written by Mildred J. Hill and Patty Smith Hill, and Warner Chappell Music reportedly pays the Hill Foundation some $2 million a year in royalties for the song. However, the producers of a documentary about the song are going to court, maintaining that it should be in the public domain, saying that it was compelled to pay Warner/Chappell $1,500 last year to use the song in their film. They claim that the sisters had actually written a song called Good Morning to All that used the melody but never used the words Happy Birthday -- and nobody seems to know who did.