Warner Music has proposed paying up to $14 million US to settle a contentious dispute over the song Happy Birthday to You.

In court filings disclosed Monday, the deal would see Warner and its publishing arm, Chappell Music, compensate those who have paid licensing fees to use the song over the years.

The settlement includes an order declaring the song officially in the public domain.

The class-action lawsuit over the universally known celebratory tune began with filmmaker Jennifer Nelson, who was making a documentary about the origins of Happy Birthday to You and was asked to pay a $1,500 licensing fee to use it in her film.

In 2013, Nelson challenged Warner's copyright claim and sued to prevent Warner/Chappell from collecting the fee going forward.

An agreement was struck in December, with details hammered out between lawyers for both sides in negotiations over the weeks since. 

The deal still awaits official approval by U.S. district court Judge George H. King. A hearing is scheduled for March 14 in Los Angeles.

In September, King ruled that Warner and its predecessor didn't hold a valid copyright to Happy Birthday to You and never acquired the rights to the song's lyrics — recognized by Guinness World Records as the most famous lyrics in the English language.

Tangled history

The case delved deeply into the origins of Happy Birthday to You, which was derived from the tune Good Morning to All, written by schoolteacher Patty Hill and her sister Mildred Hill in the late 19th century. 

The sisters assigned that song and others to publisher Clayton F. Summy Co., which included it in a children's music book called Song Stories for the Kindergarten.

When the lyrics were added to the song is less clear, with King noting in his September ruling that the first known reference came in an educator's journal in 1901. The full song lyrics made their first appearance in print 10 years after that.

Warner/Chappell began collecting royalties for Happy Birthday to You in 1988, after purchasing the company that held the copyright from the Clayton F. Summy Co. By some estimates, Warner/Chappell collected approximately $2 million US annually through licensing fees for the song.