LOS ANGELES — The music publishing company that has been collecting royalties on the song “Happy Birthday To You” for years does not hold a valid copyright on the lyrics to the tune that is one of the mostly widely sung in the world, a federal judge ruled Tuesday.

U.S. District Judge George H. King determined the song’s original copyright, obtained by the Clayton F. Summy Co. from the song’s writers, only covered specific piano arrangements of the song and not its lyrics. The basic tune of the song, derived from another popular children’s song, “Good Morning to All,” has long been in the public domain.

King’s decision comes in a lawsuit filed two years ago by Good Morning To You Productions Corp., which is working on a documentary film tentatively titled “Happy Birthday.” The company challenged the copyright now held by Warner/Chappell Music Inc., arguing that the song should be “dedicated to public use and in the public domain.”

“Because Summy Co. never acquired the rights to the ‘Happy Birthday’ lyrics, defendants, as Summy Co.’s purported successors-in-interest, do not own a valid copyright in the Happy Birthday lyrics,” King concluded in his 43-page ruling.

The lawsuit also asked for monetary damages and restitution of more than $5 million in licensing fees it said in 2013 that Warner/Chappell had collected from thousands of people and groups who’ve paid to use the song over the years.

Marshall Lamm, a spokesman for one of the plaintiffs’ lawyers, said that issue would be determined later.

In the meantime, one of the suit’s co-plaintiffs, Ruypa Marya of the music group Ruypa & The April Fishes, praised Tuesday’s decision.

“I hope we can start reimagining copyright law to do what it’s supposed to do – protect the creations of people who make stuff so that we can continue to make more stuff,” said Marya, who added she paid Warner/ Chappell $455 to include “Happy Birthday To You” on a live album during which members of her band and audience sang the song to her the night before her birthday.