Blu-Ray discs use a simple file and folder structure that is easy to understand. All Blu-ray discs use identical file structures; the main directory on a Blu-ray disc is the BDMV directory.
The BDMV directory is divided into several subdirectories. "Playlist" contains database files for video playlists, "Clipinf" stores database files for clips, "Stream" contains both audio and video files used for streaming, "Auxdata" contains sound and font files used in menus and "Backup" is home to two small files used for playback.
Audio and Video
The information used for video and audio on Blu-ray discs follows a special format called the BDAV MPEG-2 transport stream. Video and audio are handled differently on commercial BDMV (Blu-ray Disc Movie) discs than on the recordable Blu-ray discs sold for home computer use.
Starting in 2011, Blu-ray discs are going 3D. The Blu-ray Disc Association has announced a new protocol for putting 3D video on discs, and Sony has announced that they are making new players for 3D Blu-ray. 3D Blu-ray discs will use the same folder structure as older Blu-Rays but will require a new player.