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Annex: Digital Video and Data Storage
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Blu-ray Discs come in three varieties:
 Only readable BD ROM (comparable to DVD video),
 rewritable BD-RE (comparable to DVD±RW or DVD-RAM),
 and as a disc that can be written to only once BD-R (comparable to
DVD±R).
Super Video CD (SVCD)
The Super Video CD (SVCD) is a technological advancement of the video
CD. SVCDs are also like VCD-specified CD-ROMs which can be played
using either a Super Video CD player (connected to the television), or
directly with the CD-ROM drive of a computer. Many DVD players can also
play SVCDs. MPEG-2 and the increase of the data transfer rate makes it
hard to tell videos from videos in DVD quality apart.
Resolution: SVCDs use the better MPEG-2 encoder in a standardized
resolution of 480 x 576 (PAL). The MPEG-2 format offers a maximum
resolution of up to 720 x 576 points and improved compression methods
characterized by excellent image definition and homogenity.
Hard disk capacity: An average 90-minute movie must be spread across 3
CDs. On one SVCD you can get about 30 minutes of good-quality movie.
Encoder setting: Compared to the VCD with 1.3, the data transfer rate is
doubled to 2.6 Mbit/s.
MPEG-2 format introduces the so-called variable bit rate (VBR). In contrast
to the constant bit rate (CBR) of the MPEG-1 encoders, this encoder has
the option of using more bits for movement-intensive sections, as well as
saving bits if picture content remains the same.
Video CD (VCD)
Video CDs are specific CD-ROMs for storing videos in certain forms.
Compression takes place using the MPEG-1 codec. VCDs can be played on
either a video CD player attached to a television or directly via the
computer's CD-ROM drive. Most DVD players can play VCDs.
Resolution: VCDs can play movies with a maximum resolution of 352 x 288
pixels (PAL) or 352 x 240 (NTSC) at 25 pictures per second. The resolution
of a VHS cassette offers for instance 300 x 360 pixels. More important than
the resolution is the use of a good MPEG-1 encoder. Since video images
constantly change, errors cannot always be perceived by the viewer.
Hard disk capacity: A VCD can store about 70 minutes of video. A typical
motion picture must therefore be stored on two VCDs. In order to get as
much video data on a normal CD as possible, one must forego correction
information on VCD/SVCD formats within the individual sectors (sub-