The plaintiff also claims that he had discussions with Usher's mother in 2009 regarding re-recording the song and touring with Usher. On occasion, Usher's mom acted as his manager. She said Usher heard the song and liked it.
To establish copyright infringement, a plaintiff must show (1) ownership of a valid copyright, and (2) infringement of the owner's right to:
- reproduce the work,
- prepare derivative works,
- distribute the work,
- perform the work, or
- display the work.
Without direct evidence of copying, infringement is established by comparing the degree of access a defendant had to the copyrighted work with the degree of similarity between the two works. The more access a defendant had to a work, the less similarity is needed for infringement. The less access a defendant had to a work, the more similarity is needed for infringement.
"Access" does not refer to the theoretical availability of the work to a defendant. For instance, you do not have access to every book in the world that has a copyright registration. You only have access to those books you have been exposed to, or those that are well-known.
If a defendant did not have much access to a work, he or she may have independently created it. If a work was independently created, there is no infringement. On the other hand, if a given work was widely disseminated and everyone knew about it, there is a high level of access and the chance of independent creation is very low.
Sometimes access can be proven, which appears to be the case here. Usher's mother said that Usher liked the song. If access is proven, the plaintiff would not need to show that the two songs are very similar. But it appears that the songs are very similar. (I have not listened to either song.)
Unless the plaintiff's account of events is incorrect, or if one of the exceptions apply that would negate improper appropriation, Usher and Bieber are probably liable for copyright infringement.