Online Media Technologies AVS DVD Copy, Manual

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Blank discs are usually available in the following sizes (block sizes approximated).
21 minutes = 94500 blocks
63 minutes = 283500 blocks
74 minutes = 333000 blocks
80 minutes = 360000 blocks
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Digital Versatile Discs
In January of 1995, Sony was the first to showcase Digital Versatile Disc technology after having
announced co-development six months earlier. Three weeks later, Pioneer, Time Warner, and Toshiba
announced their own version of DVD, which had major differences from the format developed by
Philips and Sony. Immediately disputes started over which format should be used, since each had their
own advantages and disadvantages.
The disputes did not stop until May of 1995, when a major report was released by leading hardware
and software manufacturers (Apple, Compaq, Fujitsu, HP, IBM, and Microsoft), stating that the two
formats were not going to be supported by the industry when there were clear advantages in using
one format. The result was a mix of the two formats and the formation of the DVD Forum by all
companies involved in the two original formats (Matsushita, Mitsubishi, Pioneer, Philips, Hitachi, JVC,
Sony, Thompson, Toshiba, and Time Warner).
In 1996, the specifications for DVD-ROM and DVD-Video were finalized and DVD players began to ship
to market. One year later, the DVD Forum worked on the specifications for the first recordable (DVD-
R) implementation of DVD. In November of 1997, Pioneer announced the first DVD-R drives, while
Matsushita and Toshiba released the first DVD erasable (DVD-RAM) drives.
During 1998, a new coalition was formed to develop re-writable discs specifically for storage of data
based on 25-year-old CD patents. This format was initially called DVD+RW and was not allowed to use
the DVD logo after the DVD Forum ruled that it could not be used in the branch technology. While the
technologies between the two formats are similar, licensing rules dictate differences, some of which
can be witnessed in the logo branding of devices and media.
Much like Compact Discs, Digital Versatile Discs are comprised of a continuous spiral of blocks (or
sectors) starting from the center hole ending at the outer rim of the disc. The blocks are only of size
2048 bytes, making the format less complicated.
There are several types of DVD discs depending on their capacity and on the medium type .
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The main types of DVDs that differ as to their capacity are: