Vob

Vob or Video object file is a format of electronic files present on most current DVD:

" DVD video" , produced by industries audio-visual and sold in the trade
DVD +R, or - R, engraved starting from various sources, then finalized
the DVD +RW which do not need to be finalized)
the DVD - RW engraved in video mode, and finaliséset DVD-RW engraved in " VR" mode; ,

in opposition to the other standard. VRO, much less spread, used on the DVD-RAM and DVD - RW engraved in mode VR.

Contents of the files present on a current DVD

On a Video DVD

The DVD Vidéo are discs which were engraved, then " finalisés" to be readable by all the readers of DVD.

In addition to the files .vob, they contain files .bup (for Back UP) and .ifo (for InFO, giving information associated, chapitrage, menus, etc).

Such a file .vob can contain:

video screens (generally one)
various audio screens (various languages and alternatives)
the various subtitles
menus.

On a traditional DVD (video DVD), the first file never contains video.

Deciphered files .VOB are neither more nor less than one flow MPEG-PS.

On a DVD +R

A DVD +R, engraved by oneself (and not yet finalized), contains a Track01.cda file, which is not readable by all the readers of DVD.

It is the process of finalization which will transform this file into the structure of files and repertories which characterize the video DVD and make them readable by a standard reader.

On a DVD +RW

The DVD +RW have on the other hand the advantage of being readable by many readers, if they are not most current any more. They do not need to be finalized. A disc +RW contains:

a repertory VIDEO_RM, containing itself:

a VIDEO_RM.bup file (for Back UP)
a VIDEO_RM.dat file (for Dated)
a VIDEO_RM.ifo file (for InFO), giving information associated: chapitrage, menus, etc

a repertory VIDEO_TS, containing itself one or more series of 3 files of the form:

a file VIDEO_TS.bup
a file VIDEO_TS.ifo
a file VIDEO_TS.vob

This repertory VIDEO_TS can thus contain, for 4 " titers" video:

a file VIDEO_TS.bup
a file VIDEO_TS.ifo
a file VIDEO_TS.vob

a file VTS_01_0.bup
a file VTS_01_0.ifo
a file VTS_01_1.vob

Multiplexing of the audio stream and video, and possible conversion into MPEG

Audio stream (mp2, ac3, etc) and videos (mv2) are multiplexed (narrowly overlapping), in a file .VOB. VRO or .MPG for example, so that at every moment they are read at the same time and thus synchronized.

The démultiplexion is the opposite operation, making it possible to separate the video stream and the audio stream from the video files, and thus to obtain 1 video file + 1 audio file.

To convert a file .VOB into a file MPEG (.mpg), also mixing 2 flows, it is thus necessary to again join together (to multiplex) these two flows, according to standard MPEG (MPEG 2 for quality DVD, and MPEG 4 for quality Div X). This operation is not always necessary, since certain software accepts the video stream and audio separately.

The conversion of a file .VRO into a file .MPG follows the same principle, just as the possible conversion of a file .VRO into a file .VOB, or the reverse transformation.

In certain cases it is enough to re-elect files .VOB in .MPG to be able to use them, but the loss of the sound is often with go.

Use of files .VOB

Of the software like " Super" or " FairUse" can convert (and compress) files .VOB with the format which is appropriate.

a software like " VirtualDub-MPEG2 1.6.11" reads files VTS_01_1.VOB, famous beforehand in .mpg, to make assembly of it. The result of the assembly can be transcribed in DivX or another format, but not in MPEG1 or MPEG2 (little compressed formats vidéo+audio). " Avidemux 2.3" the encoding of vidéos allows towards several formats (MPEG, MP4, AVI, GMO…) by using many codecs (H263, MPEG4, XVID or x264 for video, Blade, FAAC, Vorbis, WAV, AC3 inter alia for the audio).

a software as CD_Roller often makes it possible to recover the engraved data, become illegible, under this format .vob on a DVD, CD, or VCD.

References

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