Chances are you've watched many VOB files without even
knowing it. VOB is the file extension for DVD Video Object, and is the multimedia container format used on all standard video DVDs. If you place any
video DVD into a computer drive and navigate to the files on the disc, you
should see the VOB files in a directory called Video_TS.
One way to copy the "feature" video on the disc is to find
the VOB with the largest file size and drag it to your hard drive.
MPEG-2 Compression
VOBs use MPEG-2 encoding standards. MPEG-2 is a combination of a video and
audio codec using a lossy compression method.
Requiring the use of a specific video encoding process has a
few benefits, but also some drawbacks. By requiring the use of a single codec,
it is easier to incorporate hardware support for the format because all videos
are encoded with the same method; that way a single algorithm can be used to
decode the video for playback.
The problem with requiring the MPEG-2 program stream, or any
specific encoding method, is that you are stuck with one compression method
even as newer and better techniques are developed. Nowadays, there are far
better codecs than MPEG-2, and VOB files are rather large compared to many
other container formats.
Computer Playback
Almost any computer can play VOB files with no special software or filters
needed. However, sometimes it is necessary to rename the file extension to .mpg
for the media player to recognize the video file.
Untouched
VOB is the preferred format for storing DVD rips because the file remains
"untouched" from the original on the DVD itself. Encoding the video into a
different format would save on disc space, but there is also a chance of
quality loss.
This does not mean that most pirated DVDs are in VOB format,
because they aren't. Although VOB is the preferred format for storing DVD rips,
it is far from the best container format. Other containers and compression
techniques result in a much smaller file sizes, which are preferred for online
distribution.
If the source of the video is something other than a DVD such
as a Blu-ray Disc or television screen capture, there is almost no reason to
store the file as a VOB.
Burning to DVD
In order to burn a VOB file back to DVD in its untouched state, you will also
need the corresponding IFO and BUP files. IFO files include information needed
by the player such as chapters, subtitles, and additional audio tracks. BUP
files are just backups of the IFOs.
As you know, discs can scratch easily and warp after time.
Anyone backup their DVD collection to VOB or any other format?
More Info:
Afterdawn: VOB
Wikipedia: VOB
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