Sony Handycam DCR-DVD100 Technology Handbook page 21

Laser
The DVD Handycam recording system uses a short-
wavelength red semiconductor laser device to record data.
This device passes current to a semiconductor and emits a
strong beam of light. Gallium arsenic is used to generate the
short-wavelength red laser beam that reads digital data on a
DVD disc.
Linear PCM Recording
Linear PCM (Pulse Code Modulation) is an audio system that
converts analog to digital signals without compression; it is
used primarily in high fidelity music recording. DVD
Handycam camcorders do not use Linear PCM recording.
MPEG
MPEG (Moving Pictures Experts Group) is an international
group that establishes industry-wide standards for digital
signal compression. These standards are known as MPEG 1,
MPEG 2, MPEG 4, etc.
MPEG 2
MPEG 2 is a digital standard for demanding video
applications. It offers high quality images with data
compression that reduces the amount of data that must be
processed. Rather than processing complete video frames,
the MPEG 2 system processes only the differences between
adjacent frames.
MP@ML
The MPEG 2 standard allows various parameter setups for
picture formats and coding modes. MP@ML (Main Profile at
Main Level) is the parameter setup adopted for DVD-Video
and DVD-VR (Video Recording) applications. "Profile" refers
to the combination of functions provided; "Level" refers to the
level of resolution and frame rate.
Numerical Aperture
Numerical Aperture (NA) value determines the performance
of an object lens; the larger the value, the more data can be
written at any one time.
Optical Pickup
This device combines a short wavelength semiconductor red
laser, a pair of 45-degree mirrors, an object lens and a
photodiode. In the DVD Handycam system, light emitted from
the laser is bent at a 45-degree angle, passes through the
object lens, reflects off the surface of the DVD disc, is
concentrated by the object lens and detected by the
photodiode.
Object Lens
This lens performs two tasks: first, focusing the laser onto the
disc surface; second, collecting the reflected laser light and
concentrating it on the photodiode detector. The performance
of the object lens largely depends on the value of its
numerical aperture (NA).
Pit
Pits describe the microscopic hollows within the surface of a
DVD-ROM or CD-ROM disc. Data is read in a spiral motion
and is determined by the length and number of pits that
occur. The discs used by DVD Handycam camcorders do not
have pits; instead, their data is carried by changes in
reflection on the disc's surface.
Playlist
The function that arranges movie scenes and still images on
a DVD disc. Playlists can be set up for editing and playback
purposes; recorded scenes and still images are not changed
by being put in playlist order.
Track
A data-recording field in the shape of a spiral or concentric
circle. CD and DVD tracks have a spiral structure; floppy disc
and hard disc tracks are concentric. The distance between
adjacent tracks is called "track pitch."
Variable Bit Rate
Variable Bit Rate (VBR) changes its data conversion process
depending on the amount of movement (or "dynamics") in a
given scene; its purpose is to reduce data requirements to a
minimum while maintaining high image quality.
Visual Index
A DVD Handycam function that displays movie scenes and
still images as "thumbnail" images on a multi-image screen,
making it easy to find a specific scene or image for playback.
• Manufactured under license from Dolby Laboratories.
"Dolby" and the double-D symbol are trademarks of Dolby Laboratories.
• Microsoft and Windows are trademarks or registered trademarks of Microsoft Corporation in the
United States and / or other countries.
• PlayStation is registered trademarks of Sony Computer Entertainment Inc.
• All other product names mentioned herein may be the trademarks or registered trademarks of their
respective companies. Furthermore, "™" and "®" are not mentioned in each case in this manual.
D V D H a n d y c a m T E C H N O L O G Y H A N D B O O K
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