DVD uses UDF/ISO9660 file system. UDF (Universal Disk Format), which was originally used to write and rewrite rewritable disc. It is the DVD standard file system.
ISO9660 is compatible with your computer's operating system.
The following diagram is published DVD disc of the directory structure, you
can see there is a section of this DVD (Session), a light-rail (Optical track),
using DVD discs UDF/ISO9660 default file system. In this way, it can be played
both in DVD players and on the computer.
DVD-ROM is the
basic format of DVD that is compatible with computer system. In the Windows
Explorer, it is very easy for the computer to read the files in the DVD-ROM, it
can be as easy as read local files on the hard disk. DVD-Audio and DVD-Video is
the disc with a format based on DVD-ROM. Audio and Video disc has the same
directory structure as the picture shows. The picture shows a typical directory
structure of DVD. In the root of DVDVLUME or VOLUME, there are two contents,
AUDIO_TS is to store audio data, VIDEO_TS is to store video data. Therefore, the
disc has no files in the AUDIO_TS directory. Because of this, you can also
customize the directory structure. The following diagram is a film disk named
"Angel Will match".
In the picture,
the home directory is defined as "Angle will match", there is only one content
called VIDEO_TS that cancel the content AUDIO_TS. Now, let us look at the
VIDEO_TS directory is what files? See the figure below.
There are three
types of VOB, IFO, and BUP.
IFO is the information file, but is the backup
files and vob is the Video Object files, for the DVD-Audio, which is the AOB,
audio object files stored in AUDIO_TS.
IFO file is to control the play of VOB
files. IFO files stores the information on how and when to play the data in the
VOB files, such as the start and end time of paragraph, the position of audio
data stream, position of subtitle stream and so on. DVD player and computer
shall read IFO files to play the films with proper order. BUP is the backup of
information files. As IFO files are very important for the proper play of film,
so it needs a backup to ensure the related information can be read even if the
IFO file errors. VOB file is to store the video data stream, audio data stream,
multi-angle, multi-language and multi-subtitle data stream as well as the
information on providing menu, button data, video standard, aspect ratio and so
on. As a VOB file can store a primary video stream and several multi-angle video
stream, 8 digital audio tracks, 32 data stream of subtitles, DVD has audio of 8
languages, 9 angles and subtitles of 32 languages.
Now let's look at the
file name, there are two types of file names: VIDEO_TS and VTS_xx_y. TS is time
stamp. VTS is short for video title set. xx is a double digit number, from 01 in
sequence, the largest to 99. It stands for title number, a maximum of 99 title
numbers. A disc has at least one title. y is a number, starting from 0 to 9. It
is the sub-heading number, 10 sub-heading at most. One title has at least a
subheading of "0" and "1" two sub-headings. The figure shows: This CD-ROM has
"01" and "02" two headings. The head 01 has the sub-title of "0" and "1" two
sub-titles, 02 has the sub-titles from "0" to "5" , in all 6 sub-headings. The
number of the title is determined by the movie clip edited and synthesis
settings. For example, we can set title sequence and the copyright notice, film,
video shooting Snapshots as three headings. We can also join the first two
letters or merge the last two titles and form two titles. Or even combine all
the three titles into a head. IFO files with a sub-heading "0" is to store
information on the scene, language, subtitles, and so the option menu
information. Sub-title "1" Start is to store VOB video files. Under the heading,
the size of each sub-VOB file should be less than 1GB (above chart). If the VOB
file is larger than 1GB, it can not be played on a PC. The VOB file size is
limited, so the video files is split into several sub-headings and played by
sequence. Though these documents are divided in form, but the program chain
(PGC) is seamlessly linked, making a coherent film, when played DVD
VIDEO_TS and VTS_xx_0 may contain files with the extended name of
IFO, BUP, and VOB. Sometimes, there will be no VOB files, take the above picture
for example, there are only IFO and BUP files. DVD discs have VMG in each disc
and VMG is stored in the VIDEO_TS.IFO files, which stores the panorama
information such as region code, selectable menu and so on. When the DVD disc is
put into the DVD-ROM, the player shall first find the file VIDEO_TS.IFO.
For more information: http://www.powerdatarecovery.com/cd-dvd-resources/dvd-file-system.html