Sony RDR-GX7 User Manual

What's DVD Recording?

DVD-Video is now the standard. Writable DVD is next.

Worldwide DVD player market

<K>

Units sold

100,000

75,000

50,000

25,000

1997

1998 1999 2000 2001 2002

Since its introduction in 1996, DVD-Video fast became the new world
standard for movie and concert video enjoyment, with extremely high quality
picture and sound reproduction. Not only have DVD players become
commonplace, DVD drives are increasingly employed in computers, game
devices and other electronic equipment. DVD is truly a versatile new storage
medium across a wide spectrum of applications.

Naturally, the time has come for writable DVD. High picture and sound
quality combine with many versatile playback functions to make this the
media of choice. The dream of high-quality digital disc recording in the
home, not only for audio/video entertainment, but also for computer storage, has
now become a reality as a media suitable for the era of broadband
communications.

The total number of DVD playback units, including PCs and game equipment with
DVD drives, is expected to increase greatly in the near future.

There are several different writable DVD format
specifications. Let’s take a look at the common features
and differences of each.

Writable DVD comes in several different formats.

Physical format Logical format

Write-once

Rewritable

Writable DVD formats are a combination of physical and logical formats.

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DVD Compatible type

Video Recording (VR)

type

Digital recording with
high image and sound quality.

Compact with
very large data capacity.

Random access for
superior operation.

Laser pickup for high-quality playback,
time after time, with no disc wear.

Writable DVD has these superior features.

Storage and playback of digitally recorded video
and audio with superior image and sound quality.

Up to 4.7 GB of data can be recorded on a CD-sized 12 cm optical disc.
Quick random access to image and sound without the need for cueing or rewinding.

Non-contact optical reading system is impervious to wear during repeated playback,
and is highly resistant to the effects of dirt and scratches, for superior storage characteristics.

Writable DVD

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Common features of

Compression in field unites.
(The image is digitalized in
field units and compressed.)

Compression on time axis.
(The imaage is compressed by
determining the volume of movement.)

Compressed to

1/40th, on average.

Data volume

Time axis

Impossible

Average
transmission rate

Waste

Average
transmission rate

Variable
compression bit rate

Fixed
compression bit rate

The rate of compression is
varied depending upon data
volume to increase efficiency.

When the transmission rate is fixed,
signal transmission is inefficient,
and portions which cannot be transmitted
result in deterioration of playback quality.

writable DVD

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Just like DVD-Video, writable DVD digitally
records video using the MPEG-2 format,

Digital recording of both image and sound.

video recording

and digitally records audio using Dolby
Digital and other formats. This assures
extremely high quality video and audio
recording, while also ensuring playback
compatibility on conventional DVD players.

How MPEG-2 video compression works

MPEG-2

The primary digital recording formats
used in writable DVD

audio recording

Dolby Digital
Linear PCM
MPEG audio

Fixed bit rate compression & variable bit rate compression

High quality digital recording of
audio and video

MPEG-2 is a highly efficient and effective technology for the compression of video signals at
variable rates. The areas of movement in each scene are determined, and for areas where
there is no change, the volume of data representing those areas can be greatly reduced.

Writable DVD can be recorded at not only fixed transmission rates, but also at variable
transmission rates which enable high image quality recording of complex video images at the
same average transmission rate.

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4.7GB

4.7GB

Image quality

Image quality vs. recording time

10 Mbps

6 Mbps

4 Mbps

2 hours 3 hours 6 hours1 hour

Recording time

High Quality Picture and Sound Recording

2-channel audio

Video

2 hour recording

Linear PCM audio

5.2 Mbps
transmission
rate

Even if the total transmission rates and recording times are the same,
emphasis can be placed on either high sound quality or high picture quality
depending upon the allocation ratio of the audio and video signal portions.

3.554 Mbps
video transmission
rate

1.536 Mbps
audio transmission
rate

2-channel audio

Video

2 hour recording

Dolby Digital audio

4.994 Mbps
video transmission
rate

0.256 Mbps
audio transmission
rate

4.7 GB per DVD

CD 7

DVD

VHS tape

Common features of
writable DVD

2

Compact optical disc with large data capacity.

A DVD holds seven times as much data as a CD.

One side of a DVD can hold up to 4.7 GB, about seven times a CD
holds. This high data capacity enables longer recording of video
and audio.

Note:

There is also a format specification for an 8 cm DVD which holds 1.46 GB of data.

The relationship between image quality and recording time.

Recording time on a given disc varies
according to the data transmission rate. If the

12 cm discs are easy to handle, easy to store.

DVDs are the same size as CDs, just 12 cm and only 1.2 mm thick. Even
a large video collection takes up very little space. Plus, they're easy to
carry and send.

A DVD in its case is still 1/3 the volume of a VHS tape.

rate is high, image quality is better, but
recording time is shorter. If the rate is lowered,
recording time is longer, but at the expense of
image quality. Moreover, even with the same
recording time, image quality can change
depending upon the format for audio recording.

(bps = bits per second)

By varying the transmission
rate, priority can be placed
either on image quality or
on longer recording time.

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Title 1

First recording

Chapter 1 Chapter 2 Chapter 3 Chapter 1 Chapter 1Chapter 2

Title 2

Second recording

Common features of
writable DVD

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Versatile recording and playback with high reliability.

Random access for versatile operation

Confirm recorded content using the menu
function to quickly access and play any
desired sequence.

No need to cue to find blank disc space.
Just press the REC button to start recording on
the remaining blank area. It's quick and easy.

Titles and Chapters in Writable DVD

Superior storage characteristics

Since the signal is read by non-contact laser
pickup, there is no wear, even after repeated
playback or cueing operations.

No stretching or print-through as with tape,
just high quality images and sound, always.

Since it is digital, powerful error correction
systems can be used to assure greater
resistance against dirt and scratches for
highly reliable playback.

In DVD, content is organized by titles and chapters. In read-only
DVD-Video software, one movie is generally considered one
title, and within the title there are several chapters which can be
accessed through the menu. In writable DVD, one recording is
saved as one title, and within that title different chapters can be
specified. Using this chapter and title data, various playback and
editing functions can be performed from the menu.

6

Differences in
writable DVD

Physical format

1

There are write-once and rewritable DVDs

Write-once DVDs can only be recorded once, like photographic film. Rewritable DVDs can be recorded and re-recorded many times, like tape.
Each type has its own advantages, and is chosen depending upon the type of use.

Read-only

DVD-ROM

Pit

Track pitch: 0.74 microns

This type is used for DVD-video
and other playback uses. Data is
represented by the presence or
absence of a pit in the pit lanes
pressed on the disc.

Write-once

DVD-R, DVD+R

Organic dye
(groove
recording)

Track pitch: 0.74 microns

DVD-R and DVD+R are "write once" discs,
meaning they can only be recorded once.

Merit

There is no danger or mistakenly erasing or
recording over the recorded content.

What is the difference between
DVD-R and DVD+R?

While DVD-R and DVD+R both have the
same basic construction as DVD-ROM,
there are differences in their rotational
control systems and data recording
positions.

grooveland

Rewritable

DVD-RW, DVD+RW

Phase
change
material
(groove
recording)

Track pitch: 0.74 microns Track pitch: 0.615 microns

Since phase change is not permanent, DVD-RW, DVD+RW and
DVD-RAM allow data to be written and rewritten over and over.

The same disc can be used over and over.

Merit

What are the differences between DVD-RW,
DVD+RW and DVD-RAM?

While DVD-RW and DVD+RW both have the same basic construction and
performance of DVD-ROM, there are differences in the way their disc
rotational control systems and data recording positions are configured.
DVD-RAM uses a special land and groove recording configuration and
specification which enables data to be rewritten up to 100,000 times,
compared to 1,000 times for DVD-RW and DVD+RW.

Unwanted sections of the disc can be erased and
rewritten.

DVD-RAM

Phase
change
material
(land &
groove
recording)

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Differences in
writable DVD

1

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How Write-once and Rewritable DVDs work.

During DVD recording, a powerful laser beam, stronger than that used for playback,
heats up the recording material, changing it to represent the data. Write-once DVDs use
chemical change, while rewritableDVDs make use of phase change.

In write-once recording,

the organic dye is chemically changed.

During recording, a powerful laser beam is focused on the organic dye
recording material, and the heat from the laser changes the chemical
structure of the dye. During playback, the playback laser can sense which
parts of the dye have been changed by heat and which haven’t. Through this
process the [0] and [1] of a digital signal can be represented. However,
changes in the dye structure are permanent, so the disc cannot be rewritten.

Recording time

Recording material layer

Reflective layer

Playback

Laser pickup

Playback of an area
heated by the laser

Laser

Playback of an area
not heated by the laser

Required laser output during
recording and playback

Playback Recording

In rewritable recording,

the phase of the recording material is changed.

The recording material used is in crystalline form before recording.
When it is heated by the powerful laser, it becomes amorphous and
loses its crystalline structure. However, weaker laser light can be used to
slowly heat it to return it to its original crystalline form. In this way, the disc
can be rewritten over and over.

Recording time

Recording material layer

(Reflective layer)

Laser pickup

Laser

Amorphous structure Crystalline structure

Required laser output during
recording and playback

Playback Recording Erasing

Amorphous and crystalline
structures have different
reflective ratios, so the [0] and
[1] of Through this process

the [0] and [1] of a digital signal

can be represented.

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Differences in
writable DVD

DVD recording methods can basically be divided into two categories, those which place emphasis on
playback equipment compatibility, and those which enable more operation functions. Here, these are
referred to as the DVD compatible type and the Video Recording (VR) type. The DVD compatible type is for
recording DVDs which can be played on DVD-Video players, while the VR type is for taking advantage of
numerous operation functions, playing DVDs primarily with the equipment on which they were recorded.

Logical format

2

Different recording methods are used.

DVD Compatible type

Can be played on most DVD-Video players
Basic recording and playback functions can be used.

Differences in
writable DVD

Discs recorded as the DVD compatible type can be
played on any conventional DVD player. Data is
recorded from the center of the disc outwards.
Recordings made can be played on other players,
and can be given to friends and associates.

Logical format-1

2

The DVD-Compatible type has superior playback compatibility.

Video Recording (VR)

Can only be played on compatible players
Editing and other advanced functions can be used.

type

Discs which are the DVD Compatible type.

Discs for DVD-R, DVD+R, DVD-RW, DVD+RW all are the DVD Compatible type.
DVD Compatible type discs for DVD+RW have basic editing functions.

What is finalization?

This is a form of final-stage processing that enables the data recorded by writable and
rewritable formats to be played on a conventional DVD-Video player. During finalization, the
menu screen used to operate the convenient playback functions is also created.

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Unwanted scene

The original recording can be changed,
and unwanted scenes can be erased.

Original video recording

The original recording
after editing

AB C

ABC

The original recording remains as it is.
Playback order can be changed by selecting a pre-set playlist.

Original

Playlist 1 Playlist 2

Creating a playlist and editing

ABC D

DAB DBC

Differences in
writable DVD

Logical format-2

2

The Video Recording (VR) type has many unique functions.

The VR type is used for DVD-RW and DVD-RAM. The discs can only be played on compatible players,
but they feature quite a number of unique editing functions.

Recorded video scenes can be edited on the disc itself.

Editing functions such as erasing scenes in an original video recording can
be performed on the disc itself. Erased scenes can be replaced with
new scenes. In addition, the disc can be “write protected” to prevent
editing and erasing of scenes.

Virtual editing is possible by making a playlist

The original video recording can be left as it is, and in place of erasing
scenes and changing the order, a playlist can be created to enable “virtual
editing” for different playback order. Best of all, this does not reduce the
amount of available recording time on the disc.

It is possible to record broadcasts which have been specified as “copy once.”

VR type has copy protection system on recording and it is possible to record
not only "copy free" broadcasts but also "copy once" broadcasts which allow recording only once.

Broadcasts with multiplex soundtracks may be recorded.

Stereo and bilingual soundtracks on broadcasts may be recorded, with selection of main,
sub or main + sub (stereo) possible during playback.

Note1: Although this information is based on format specifications, there may be cases when playback is not possible on actual equipment purchased.
Note2:Broadcasting stations can add copy generation control signal to programs to protect the rights of copyright holders of the contents.

Recording of "copy once" programs is limited to only once, and "copy never" program is not allowed to be recorded, though "copy free" programs can be recorded over multiple generation.

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Types of Discs and Compatible DVD Players.

DVD player

Players which can play back
DVD-RW discs recorded as VR type.

DVD-RW / VR compatible players

Players which can read the recorded
signal on a DVD-RAM disc.

DVD-RAM compatible players

DVD-RW DVD+RW DVD-RAM

DVD-R

DVD+R

DVD

compatible

(VR format)

(DVD-Video

format)

Notes:

1. Although this information is based on format specifications for playback and recording formats, there may be cases when playback is not possible on actual equipment purchased.

2. There may be cases where playback is not possible on DVD drives on personal computers or game equipment due to differences in drive type or recording format of the software.

VR

(VR format)

VR

DVD

compatible

(Video format)

DVD

compatible

(DVD-Video/Video

format)

There are cases where a recorded DVD disc can not be played back on certain DVD players due to differences in disc type
and recording format. Compatibility by disc type, recording format and type of player is indicated below.

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Writable DVD Expands Your Personal Entertainment World.

Writable DVD

DV

Oh, let's see
that part again...

Writable DVD represents a quantum leap from the world of analog video tape. It can be used to record and store not only
broadcast programming, but also personally created movie and still video images. Recorded discs can be played back on
a DVD player, a personal computer or even game equipment for an unprecedented level of entertainment versatility.

High quality recording and
playback of your favorite TV programs.

Put your video tape collection on
digital DVD for a disc library
you can enjoy over and over.

repeated playback

DVD
Recording

Put your own digitally recorded
movies and still photos on
Writable DVD for easier enjoyment.

Since recorded DVDs can be played on many
DVD players, car DVD systems, PCs and game
equipments around the world, they can be enjoyed
in many ways. A number of possibilities enable to
create a new style of

Enjoy DVD!

communication

through DVDs.

analog tape

writable DVD

repeated playback

Thank you.

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