The 'Blurred Lines' creators are still trying to reverse the Marvin Gaye verdict

The artists behind "Blurred Lines" may have lost a lawsuit last year, but it looks like they're just beginning to fight.

Attorneys for Robin Thicke, Pharrell Williams, and T.I. filed a brief Wednesday that aims to overturn a ruling that found that "Blurred Lines" had copied Marvin Gaye's "Got to Give It Up," and found the artists responsible for $5.3 million in damages and half of songwriter and publishing revenues.

The brief argues that the judge should have never allowed the trial to occur, and also claims the jury was unfairly influenced by both hearing the actual "Blurred Lines" recording and not being told to ignore parts of the song that are not protected by copyright.

The outcome of the appeal will no doubt impact other high-profile copyright battles that have been trigged by the ruling in March 2015. On Monday, indie stars Sleigh Bells officially filed a copyright infringement suit against Demi Lovato, saying that her 2015 track "Stars" rips off two of their songs.

The artists appealing the "Blurred Lines" ruling point to a a recent copyright case in which Led Zeppelin was accused of ripping off another, lesser known band in their creation of their 1971 hit "Stairway to Heaven." In that case, a jury deliberated for only one day before finding the famous rockers not guilty of stealing the opening riffs of their song.

In the Led Zeppelin case, the jury was not allowed to hear the original recordings of either song, because the copyright claim only applied to the sheet music. Instead, specially-prepared versions of each, based on the sheet music, were played. But in the "Blurred Lines" case, the jury was allowed to hear the actual Pharrell Williams-produced recording, along with a specially-prepared version of "Got to Give it Up." The lawyers for Gaye's estate were also allowed to testify about the sound of the "Got to Give it Up" recording, which the brief says should not have happened.

Peter Anderson, the lawyer who represented Led Zeppelin in their case, declined to comment for this story.

William Hochberg, a Los Angeles based attorney who regularly represents musicians, agrees that the original ruling of the "Blurred Lines" case was wrong.

"With the 'Blurred Lines' case, you have high hat cymbal sounds, crowd noise, falsettos," he said in a phone interview. "Nobody owns the falsetto voice or the crowd noise, or that vibe that exists in both 'Gotta Give it Up' and 'Blurred Lines'." These elements, he said, are not copyrightable.

"If Marvin Gaye's estate had come to me [with that case], I would have turned them down."

He says that since the "Blurred Lines" lawsuit, he has seen a lot of what he calls "frivolous" lawsuits popping up, which he feels is having a chilling effect for the creative community. "If this is overturned, it would cause a sigh of relief among those who are creating music. I'm the first one to go to bat for someone has been ripped off, but sometimes there's nothing there."

But, he says, this appeal is a long shot; it is difficult to get an appeals court to overturn a jury's decision.

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