BTS: Anniversary Music
From Halopedia, the Halo wiki
BTS: Anniversary Music is a 343 Industries Behind-the-Scenes documentary video that offers a look at the developmental process of the remastered music of Halo: Combat Evolved Anniversary. The video features exclusive interviews of Skywalker Sound and 343 Industries employees as they discuss the re-composition of the original Halo soundtrack. It was first released on YouTube and Halo Waypoint on October 24, 2011.