Sony RDR-GX7 - Manual (Page 2)

What is the capacity of a DVD?
The current crop of recordable DVD discs holds approximately 4.7 GB*. To understand why some may state a capacity of 4.4
GB, we must look at a variation in math used to determine the capacity.
For ease in remembering numbers and doing mental calculations, many people assume that one million bytes equals 1 mega-
byte (MB). This is close, but not quite true. In reality, 1 MB actually equals 1,024 kilobytes (KB), not 1,000 KB. So if you do the
math using 1 MB = 1,000,000 bytes, you will find that using 1 GB = 1000 MB will return a capacity of 4.7 GB (4700000000
bytes divided by 1000 divided by 1000 divided by 1000). However, if you use the truer 1 MB = 1,024,000 bytes, it will return a
figure of approximately 4.4 GB (4700000000 bytes divided by 1024 divided by 1024 divided by 1024). This greatly increased
capacity over CD gives you the power to put your creative and organizational desires on the fast track to success.
A DVD disc holds the equivalent of:
n 6½ CD-Rs, or
n 440 ZIP 100 MB discs, or
n approximately 3200 floppy discs.
What can I do with DVD?
You can use recordable DVD media for data storage and audio/video recording.
STORAGE:
n Recordable DVD media provide 4.7 GB* of storage, enabling you to back up large amounts of data.
n The large capacity of a recordable DVD can contain high-quality video, better-than-CD quality audio, and still have room
for special features and multimedia applications.
n Unlike your computer’s hard disk drive where you have to delete files to make room for more, once a DVD is filled up,
simply replace it with another and continue recording.
VIDEO:
n Recordable DVD allows you to watch personal home movies you have created and edited for playback in many DVD
players. You can fit anywhere from 1-4 hours of video on a single disc, depending on the encoding.
n Because DVDs are digital, you will not experience generational loss. This means that every time a DVD is copied, the copy
offers the same pristine quality as the original DVD.
n DVD offers some great advantages over videotape, such as:
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Vastly superior detail and picture quality.
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No need to forward or rewind a tape to find a particular point.
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Higher quality audio, even better than a typical CD.
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No signal degradation because no reader mechanism touches the media.
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Ability to duplicate a DVD many times without losing quality.
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Creative and interactive menu systems.
How much video can a DVD hold?
Size versus quality is a regular tradeoff in the video world and is an inexact science. Due to the size of video files reflecting much
of the content of the video, there is no fixed number for recording a video of a certain size with a particular format—all sizes are
approximate and vary.
Example: If you filmed a 10-minute nightly news segment and a 10-minute clip of the Superbowl with the same camcorder
and encoded both videos with the same compression, would the file sizes differ? Yes, because the news anchor and picture in
picture graphic over her shoulder change very little in comparison to the constant action of the football game and its changing
shapes, colors, moving players and thousands of excited fans in the background. The Superbowl file size is visibly larger due to
the increase in content that was filmed.