Okay, so here's the story. I took an 8 minute track from the soundtrack of a movie, which was playing with stringed instruments and band instruments, and wrote out solo piano sheet music for it. It was a very rough transcription, and notation wise i'm sure it's not very similar to the original sheet music in any way. However, if played as notated, on a piano, it sounds pretty much like the original music. But I achieved that same result using (i'm almost certain) totally different notation, time signatures, note values, etc. I didn't have any sheet music for it, so I just wrote down entirely by ear, something that would make it sound more or less like the music when played on the piano. The owners of the original music never published real sheet music for it. Is it illegal for me to sell my transcribed music online? It has my name on it as the arranger, and the composers name as the composer. Thanks.