This is the Expanded Rock Band version with separate parts for the following instrumentation: Lead Guitar, Rhythm Guitar, Piano, Bass, Drums, Pecussion (Combined and separate parts): Chimes, Tambourine, Wind Chimes, Tympani. Horn parts include: Trumpet 1, Trumpet 2 (Alto Sax sub), Trombone 1 (Tenor Sax sub), Trombone 2 (Horn sub), Baritone Sax (Trombone sub). Full strings include: Violin 1, Violin 2, Viola, Cello. A full score is also included. Note that there is a smaller “rock band” only version available.
Check out the original here:
Trans-Siberian Orchestra - O' Come All Ye Faithful : O' Holy Night - YouTube