The Blu-ray disc uses the Universal Disk Format (UDF) 2.50 developed by the Optical Storage Technology Association (OSTA) is an open, vendor-neutral file system for data storage for optical discs and it's a compatible-friendly format for both Personal Computers and consumer electronics environments. A BDMV application has a standard file structure similar to the DVD. 

 

 

 

A BD-ROM uses the BDMV application format and its contents are organized on the disc in a hierarchy of mandatory and optional file directories and subdirectories that contain all video, audio, and data:

1. BDMV directory: contains the PLAYLIST, CLIPINF, STREAM, AUXDATA, and BACKUP directories.
   • PLAYLIST directory: contains the Database files for Movie PlayLists.
     • xxxxx.mpls files: store information corresponding to Movie PlayLists. One file is created for each Movie PlayList. The filenames of these files are in the form "xxxxx.mpls", where "xxxxx" is a 5-digit number corresponding to the Movie PlayList.
   • CLIPINF directory: contains the Database files for Clips.
     • zzzzz.clpi files: store Clip information associated with a Clip AV stream file. The filenames of these files are in the form "zzzzz.clpi", where "zzzzz" is a 5-digit number corresponding to the Clip.
   • STREAM directory: contains AV stream files.
     • zzzzz.m2ts file: contains a BDAV MPEG-2 transport stream. The names of these files are in the form "zzzzz.m2ts", where "zzzzz" is a 5-digit number corresponding to the Clip. The same 5-digit number "zzzzz" is used for an AV stream file and its associated Clip information file.
     • SSIF directory: If used, 3D Stereoscopic Interleaved files shall be placed under this directory.
       • zzzzz.ssif file: is a Stereoscopic Interleaved file that is composed of two BDAV MPEG-2 transport streams. Both streams include a MPEG-4 MVC view video stream for the left and right eye, respectively. This file is used only when a 3D video is played back. The 5-digit number "zzzzz" is the same as the number used for the AV stream file "zzzzz.m2ts" which includes the MPEG-4 MVC Base view video stream.
   • AUXDATA directory: contains Sound data, Image, Font, and asset files.
     • sound.bdmv file: stores data relating to one or more sounds associated with HDMV Interactive Graphic Streams applications. This file may or may not exist under the AUXDATA directory. If it exists, there shall be only one sound.bdmv file.
     • aaaaa.otf file: stores the font information associated with Text subtitle applications. The names of these files are in the form "aaaaa.otf", where "aaaaa" is a 5-digit number corresponding to the Font.
   • BACKUP directory: contains copies of the "index.bdmv" file, the "MovieObject.bdmv" file, all the files in the PLAYLIST directory, and all files in the CLIPINF directory.
   • index.bdmv file: stores information describing the contents of the BDMV directory. There is only one index.bdmv file under the BDMV directory.
   • MovieObject.bdmv file: stores information for one or more Movie Objects. There is only one MovieObject.bdmv under the BDMV directory.
   • BD-J Object directory: contains BD-J objects.
   • xxxxx.bdjo file: stores information for one or more BD-J objects.
   • JAR directory: contains Java Archive files (JAR) for BD-J mode.
     • xxxxx.jar file: It's a package file format typically used to aggregate many Java class files and associated metadata and resources (text, images, etc.) into one file for Java programs. There can be many JAR files in the JAR directory. The max file size is 4 MB, but assets can be stored outside the file.
   • META directory: Subdirectory containing disc metadata and information.
   • DL directory contains the DL XML metadata file
   • dlmt_000.xml file: which contains the metadata for the whole disc and would include the title of the movie (or regarding content as a whole), and the JPEG/PNG image thumbnail. Optionally, you can have multiple titles in a single disc with different thumbnails.
   • xxxxx.jpeg: large 640x320 title thumbnail icon.
   • xxxxx.jpeg: small 416x240 title thumbnail icon.
   • ES directory contains the ES XML metadata file
   • esmt_000_xxxxx.xml: which includes the information for Title Scene Search, this is where the names of titles would be located along with keywords for searching them. Also, individual thumbnails for each title would be stored here.
   • TN directory contains the TN XML metadata file
     • tnmt_000_xxxxx.xml: This is for Track/Chapter display where the names/text for individual tracks and chapters would be located.

1. CERTIFICATE: Directory containing BD-J security certificate information.
   • app.discroot.crt: contains the BD-J root certificate.
   • id.bdmv: contains the disc's ID information.
   • BACKUP directory: contains copies of the "app.discroot.crt" file, and the "id.bdmv" file.

1. AACS: Directory containing the Blu-ray's DRM AACS decryption files.
   • MKB_RW.inf file: Read/Write Media Key Block.
   • Content001.cer
   • Content002.cer
   • ContentHash001.tbl
   • ContentHash002.tbl
   • ContentRevocation.lst
   • CPSUnit0000x.cci: CPS Unit Usage files.
   • mcmf.xml
   • MKB_RO.inf
   • MKB_RW.inf
   • SKBx.inf
   • Unit_Key_RO.inf: AACS CPS Unit Key.
   • DUPLICATE: Directory of duplicated AACS files.

1. BDSVM: Directory containing BD+ content code files (optional for studios, not part of the BD standard).
• xxxxx.svm: BD+ content code file.
• BACKUP: Directory of backup BD+ content code files.

Author(s) : Æ Firestone