Christian rap tune's copyright upheld; Katy Perry awaits the 'bill'

After a jury's verdict that Katy Perry's 2013 hit "Dark Horse" improperly copied a 2009 Christian rap song, Perry and other defendants will soon learn how much they owe for copyright infringement.

The penalty phase will begin Tuesday with opening arguments and will ultimately determine the price tag for the damages owed to Marcus Gray and the two additional co-authors of the song "Joyful Noise," released under Gray's stage name Flame. Testimony will give jurors a look into the finances behind "Dark Horse," a radio hit that earned Perry a Grammy nomination and obtained a spot in her 2015 Super Bowl halftime performance.

Perry's song in question -- a hybrid of pop, trap and hip-hop sounds -- was the third single off her 2013 album “Prism.” It also spent four weeks atop the Billboard Hot 100 chart in early 2014.

Gray's attorneys argue that the beat and instrumental line featured through nearly half of "Dark Horse" are substantially similar to those of "Joyful Noise." Gray wrote the song with his co-plaintiffs, Emanuel Lambert and Chike Ojukwu.

However, Perry's attorneys argue that the song sections in question represent the kind of simple musical elements that if found to be subject to copyright would hurt music and all songwriters.

“They’re trying to own basic building blocks of music, the alphabet of music that should be available to everyone,” Perry’s lawyer, Christine Lepera, said during closing arguments last Thursday.

A musical expert defended the songwriters, saying that the patterns in dispute were as simple as "Mary Had a Little Lamb." To the contrary, the jury believed the beat and riff were original enough to merit a copyright.

Throughout the seven-day trial, the defendants also testified that they had never heard of Gray nor his song and that they did not listen to Christian music. But Gray's attorneys pointed to his large following, the success and circulation of "Joyful Noise," and the fact that the album the song was featured on was even nominated for a Grammy.

Gray's song has more than 2.4 million views on YouTube and has been played more than 3.3 million times on Spotify.

Despite the usual tension of a courtroom, Perry did manage to bring a laugh to the proceedings on its second day. While her lawyers struggled to get her song "Dark Horse" to play in the courtroom during her testimony, Perry joked, "I could perform it live."

Technical issues were resolved, and both songs were played back-to-back in their entirety to wrap up closing arguments.

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In addition to Perry, Capitol Records, as well as her producers, Dr. Luke, Max Martin and Cirkut -- who came up with the song’s beat -- were found liable.

The Associated Press contributed to this report.