Understanding BDMV
BDMV is an acronym for Blu-ray Disc Movie. It refers to a specific file system format and directory structure utilized for storing content on Blu-ray Discs, predominantly for commercial movie releases and other high-definition video programs.
This format is designed to enable Blu-ray players to accurately parse and render the disc's contents, which include the primary video and audio streams, multiple subtitle tracks, interactive menus, and supplementary features. BDMV is distinct from BDAV (Blu-ray Disc Audio/Visual), a simpler format generally employed for user-recorded content on BD-R/RE media.
Core BDMV Structure and Key Files
A standard BDMV structure typically resides within a root folder named "BDMV" and encompasses several essential subdirectories and files:
- STREAM: This directory contains the primary audio and video content, usually encapsulated in .m2ts (MPEG-2 Transport Stream) files. These are the core media files.
- CLIPINF: This folder holds clip information files (with a .clpi extension) corresponding to each .m2ts stream. These files store metadata attributes such as video resolution, aspect ratio, frame rate, and audio codec specifications.
- PLAYLIST: This directory contains playlist files (with an .mpls extension). Playlists define the specific playback order of video clips, facilitating features like different movie versions, seamless branching for multiple angles, or director's cuts.
- BACKUP: This folder serves as a repository for duplicate copies of critical database files, including and . It may also contain backups of the
CLIPINFandPLAYLISTfolders to ensure data integrity and facilitate error recovery. - This crucial file, located at the root of the BDMV directory, acts as an index describing the titles and overall content available on the disc.
- Also found in the BDMV root, this file defines executable "Movie Objects" which manage the interactive navigation, playback logic, and user interface elements of the Blu-ray disc.
The BDMV specification is fundamental for the distribution of high-definition video content, supporting advanced functionalities and ensuring a consistent playback experience across compliant devices. It is a cornerstone of Blu-ray disc authoring and playback technology.
