A forgotten wedding singer is challenging for credit after a song he wrote became a major hit. The dispute forms the basis of a new musical comedy film, “Repeating Melody,” starring Paul Rudd and Nick Jonas. The film, set to release next week, centers around the singer’s fight to be recognized for his work. Rudd and Jonas play key roles in the unfolding drama. “Repeating Melody” promises a lighthearted take on the complexities of music ownership and artistic recognition. The film is expected to draw attention to issues of copyright and the struggles of lesser-known musicians. It blends comedy with a compelling narrative about pursuing rightful credit.