Structure of a VIDEO

 

Overview

Specifications of the DVD-VIDEO standard are quite different from those of the DVD-ROM.

To be precise, the only common thing is the media they use.

A Video DVD is divided in several areas : the Volume area, Video area and the Others area.

• Volume area contains the structure of the data needed to access the disk content.
  
  There are two filesystems in this area:

Extended ISO9660 to insure compatibility with existing computers filesystems,
MicroUdf compatable with forthcoming computers filesystems.

• Video area contains all real datas files (images, sounds etc.). These files are organized in a very special way on the physical disk surface.
• Others area is present to manage others applications of the DVD, for instance a DVD-Rom application.

When a DVD contains both Video DVD area and Others area, it is called a Bridge-DVD disk.

Structure of the Vidéo DVD area

The filesystem of a VIDEO DVD disk is built in two folders at the root :

• the AUDIO_TS folder
  So far this folder is unused and must be empty.
  
  
• the VIDEO_TS folder
  Contains all the video and audio related files
  

Following files may occur to be in this folder :

\VIDEO_TS\VIDEO_TS.IFO
\VIDEO_TS\VIDEO_TS.BUP
\VIDEO_TS\VIDEO_TS.VOB (optional)
\VIDEO_TS\VTS_nn_0.IFO
\VIDEO_TS\VTS_nn_0.BUP
\VIDEO_TS\VTS_nn_0.VOB (optional)
\VIDEO_TS\VTS_nn_1.VOB
\VIDEO_TS\VTS_nn_n.VOB  (optional)

This file structure is generated by the Video DVD building system.

 

*.IFO files are program files. They contain control instructions whiach allow the Video DVD player to handle the movie

*.BUP files are an exact image of the *.IFO files. They are mandatory on a Video DVD and are used in case of an error while reading an *.IFO file.

*.VOB files contain all the datas.

VIDEO_TS.IFO, VIDEO_TS.BUP and VIDEO_TS.VOB files are compose the Video Manager. It is the first program loaded by the DVD player when the PLAY is launched.

Video Manager usually launches a short introductory logo movie and the main menu where you choose language subtitles and chapters.

All those are contained in ressources located in the VIDEO_TS.VOB file. This "main index" file can't point directly on *.VOB files, only on a Video Title set.

VTS_nn*.* files are Video Title Set where :

Each _nn is the Video Title set number.This number goes from 01 to 99, so there can be up to 99 Video Title sets on Video DVD. A Video DVD must have at least one Video Title set.

Each Video Title Set is actualy pointing to one or several data (at least!) files on the disk, containing the video and audio. There can be from 1 to 9 of these *.VOB files, according to the total video size. These files are named VTS_nn_x.VOB, where x goes from 1 to 9. This is a physical way to span a (too big) VOB file.

Each one of these files must be smaller than 1 GigaByte and the sum of all files must be smaller than 8,5 GigaBytes per side on a double layered DVD disk.

A Video Title Set may contain (or not) a menu or intro short movie. In this case the "intro/menu file" is named VTS_nn_0.VOB.

For instance, let's think of a demo DVD which presents several directors, with several small trailers for each director. There could be a Video Title Set for each director. Each Video Title Set could contain a menu allowing to select one among several movies of the same director.

So if we assume 01 and 02are director numbers and x is a trailer, we would find :

VTS_01_0.VOB as a menu file about director # 01 allowing to chose among 4 trailers VTS_01_1.VOB to VTS_01_4.VOB ,

VTS_02_0.VOB as a menu file about director # 02 allowing to chose among 7trailers VTS_02_1.VOB to VTS_02_7.VOB ,

Each VOB file is actualy a collection of 1 to 65535 Video OBjects (VOB) .

Each Video OBject has an identifier called a VOB_IDN.

A Video Object is divided in 1 to 256 cells. Cells are the smallest adressable entity of a Video DVD. They allow to point on separate parts of a mpeg file.