As a part of a movie soundtrack, whether it is acceptable depends on how central the piece is to the story. If it is just one of many original pieces, and it is not suppose to be a masterpiece, it might be adequate in its role. Again, the context is quite important.
As an example, in the movie Mr. Holland's Opus, a wanna be serious composer is sidetracked by the necessity to get a job (music teacher in a high school), the hectic extra-curricular activities related to being a music teacher, repairing relationships with his wife and son (whose deafness he did not deal with well when his son was a child). At the end of the movie, school budget cuts force him into retirement, and for his going away, a huge number of former students show up to show their appreciation for what he as done for their lives. The school orchestral has secretly been practicing the Symphony he had been writing for years and was never able to complete. The climax of the movie is the playing of this piece. It is sort of a downer that this piece is pretty bad. At least this did not totally destroy the movie because Mr. Holland's opus was not his music, but, what he did to the lives of the people around him.
It matters a lot if this piece is, or is not, central to the story.
