Sharp DV-500D User manual

1
DVD-Series
SHARP CORPORATION
T58P2DV-500D/
TECHNICAL MANUAL
DVDVIDEO PLAYER
MODELS
DV-500D
DV-550
DV-550W/X
DV-550U
DV-560S
DV-560H
ON
DIGITAL
GAMMA DIGITAL
S PICTURE
DV-S100
POWER
OFF
OFF
IN MAX
LEVEL
PHONES
COMPACT
D I G I T A L
DOLBY
DIGITAL VIDEO
DVD / VIDEO CD / CD
CONTENTS
page
1. The Birth of DVD................................................................................................3
2. DVD Features ....................................................................................................6
3. Technical Point of DVDs ..................................................................................13
4. DVD Servo Circulation .....................................................................................20
5. TRAYMECHA Control......................................................................................27
6. TRAYMECHA Timing Chart .............................................................................32
DV-800D
DV-880
DV-880X/W
DV-890S

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DVD-Series

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DVD-Series
1. The Birth of DVD
1-1 Main Specifications of the DVDVideo Player
Disc Diameter 120mm
Disc Thickness 1.2mm 0.6mm x 2
Semiconductor Laser Wavelength 650nm
Lens (NA) 0.6
Pit Length 0.4~1.87µm / 0.44~2.05µm
(Single Layer) (Double Layer)
Track Pitch 0.74µm
Sector Allocation CLV
Modulation System 8/16 Modulation
Correction System RS-PC (Reed Solomon Product Code)
14.7GB (1 Layer on 1 Side)
Memory Capacity 28.5GB (2 Layers on 1 Side)
39.4GB (1 Layer on Both Sides)
417GB (2 Layers on Both Sides)
1-2 Type of Discs
There are 4 types of discs.
(1) 1 layer on 1 side disc (2) 1 layer both sides disc
(3) 2 layers on 1 side disc (4) 2 layers on both sides disc
0.6mm
0.6mm
0.6mm
0.6mm
,,,,,,,
Side A
Side B
0.6mm
0.6mm
0.6mm
0.6mm
First layer
First layer
Second layer
Second layer
First layer Second layer

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DVD-Series
1-3 Disc Structure
Thefirstlayeronthe2-layersdisc(semitransparentreflectionfilm)doesnotreflectunlessthelaser
light is focused.
(1) 1 layer on both sides
(2) 2 layers on 1 sides
1-4 Disc Capacity
1 layer on 1 side 2 layers on 1 side 1 layer on both sides 2 layers on both sides
12cm 4.7 8.5 9.4 17
8cm 1.4 2.6 2.9 5.3
1-5 Example of the DVD’s calculating memory capacity Condition
Condition
1. More than 3.5Mbps of average image data rate
(The compression rate changes depending on the image. This is the average value)
2. Audio is Dolby AC-3, 5.1ch digital sound
3. Dubbed in 3 languages + subtitled in 4 languages
4. 133 minutes are recorded on a 1 layer on 1 side disc
Required data rate
Image Audio Subtitles Total
3,500k + (384k ×3) + (10k) = 4,692kbps(bit/second)
Required disc capacity
Data Rate Recording Duration Memory Capacity
4, 692kbps ×(133 ×60) second ÷8 (8bit = 1byte) = 4.680.270kBytes
4.7 gigabytes are required to record 133 minutes on a 1 layer on 1 side disc
Type of Disc
Disc Size
,,,,,,,,,,,
,,,,,,,,,,,
0.6mm
0.6mm
Side B
(Standard reflection film)
Adhesive layer
Side A
(Standard reflection film)
,,,,,,,,,,,
,,,,,,,,,,,
0.6mm
0.6mm
Second layer
(Standard reflection film)
Adhesive layer
(transparent)
First layer
(semitransparent reflection film)

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DVD-Series
1-6 Order and Direction of Disc Recording
There are 3 types of recording orders and directions.
1 layer disc
2 layers disc (B)
1-7 Two Discs are StackedTogether to Form DVD discs
The DVD disc structure is the stacking of two 0.6mm thin type discs, making it most suitable for
reading high density recorded data signals.
The thinner the disc, the less number of obstacles between pits notched on the optical pick up and
disc, so more precise reading can be achieved.
Additionally, stacking these same material discs together back-to-back, increases evenness,
meaningthe discwillwarp lessdueto heatandhumidity comparedtosingle 1.2mmboards. Thus,
the discs are more reliable.
Features of the 0.6mmThick Disc
1. Materialized mass capacity and high density
• Because the thickness is half that of traditional discs, it is less likely to warp or slant.
• Degree of evenness becomes much higher at assembly, with high rates of evenness and
precision.
2. Makes board-making easier and reduces production costs
• The stacked structure is highly resistant to environmental changes (heat, humidity)
• The thin structure increases the time cycle, so forming is easier stabilized
• Overall, it will cost less than 20% more than a CD.
2 layers disc (A)
,,
,,
,,,,
,,,,
2
1
Data areaLead-in area Lead-out area
Parallel track path
Center of the disc
,,
,,
Center of the disc
Lead-in area Data area Lead-out area
,,
,,,
2
1
Data areaLead-in area
Lead-out area
Middle area
Opposite track path
Center of the disc
0.6mm
0.6mm 1.2mm
Changes in temperature and humidity
DVD (stacked-together structure) CD (single board structure)

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DVD-Series
2. DVD Features
2-1 DVD is not a DigitalVideo Disc
“DVD” is often considereed the abbreviation for Digital Video Disc, but as the unified standard
for the next generation of high density optical fiber discs, the term “DVD” is not used in that way.
It has been adopted as the name of the unified standard.
2-2 Amazing Mega-Capacity
AlthoughtheDVD’ssizeisthesameasa12cmCD,oneDVDsidecanrecordhugecapacity,about
4.7GB, equivalent to approximately 7 CDs. This disc can be recorded to 133 minutes for full a
movie film, with high quality picture and sound which like a movie theater.
Additionally, it is only the capacity for one side. The 1 side 2 layer type can record 8.5GB, the 2
sides with 1 layer type can record 9.4 GB and an amazing maximum 17GB can be recorded on 2
side 2 layers type.
4.7 GB = 688 MB
●Comparison of DVD data capacity
DVD
(one side)
CD
X 6.8 CDs7 times as more
than a CD
DVD
(one side)
CD
2.2 (side)2.2 times as much a
s an LD
133 MIN = 60 MIN
●Comparison of DVD recording times (approximate)
The memory capacity of a disc is determined by the time of information and amount of data per
second (data rate). In the case of CDs, the number of quantization bits is 16, and the sampling
wavelength is 44.1kHz with 2 channels. So, the amount of data is 16 ×44.1k ×2 = approx.1,411k
bits/second = 1.411M bits/second.
ThemaximumlengthofaCD is74 minutes. Ifthe samesound fromaCDisrecordedontheDVD,
it comes to 4.7GB. That means, 37.6 (4.7 ×8), and it will come to 37.6 ×1,000 ÷1.411 = approx.
26,648 (seconds) for one side.
That is approximately 444 minutes (7 hours 24 minutes).
2-3 Secrets of Producing Large Capacity Recording and Long Hour Replay
1.Realization of large capacity recording
The track pitch is less than half of that of a CD, making it longer.
Also, the recorded amount of information is increased due to the smaller pit (less than half of
that of a CD)
Becausethepit is smaller, the laser focus needs to be smaller. To do this, the wavelength of the
laser beam is shortened and the opening of the object lens (NA) is increased.
This bigger NA increases the influence of the aberration of laser beam from the protection film
(thetransparentplasticpart). Thiscausesblurringofthelaserfocusagainstthediscinclination,
or its slippage when the pit becomes bigger, lowering the signal reading precision (increasing
noise).
Todecreasetheinfluenceofthislaserbeamaberrationfromprotectionfilm(transparentplastic
part), we decreased the thickness of the disc.
(one-half that of a CD, 0.6mm) Also ensure CD compatibility, we put 2 of the discs together.
Byputting2ofthese0.6mmthickdiscstogether,theevennessofthediscisincreased,warping
due to heat and humidity is decreased and the signal reading precision is improved.2.

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DVD-Series
λ
2. Comparison of CDs and DVDs
Item CD DVD DVD(CD)
Track Pitch 1.60µm 0.74µm 1.60µm
Minimum Pit 0.87µm 0.40µm 0.87µm
Laser Beam Wavelength 780nm (Infrared Light) 650nm(Red) 650nm(Red)
Opening of the Object Lens 0.45 0.6 0.38
Laser Focus 1.8µm 1.0µm 1.7µm
*CD mode of DVD
3.Decreasing the Laser Beam FocusWavelength
The size of the laser beam focus Φhas small λ, When NA increases, it becomes smaller.
It is determined using the following formul:
NA (Opening of the object lens) = DVD : 0.6
CD(DVD) : 0.38
Φ= NA
λ (laser beam wavelength) = 650nm
DVD Φ = 0.6 = about 1µm CD(DVD) Φ = 0.38 = about 1.7µm
NA shows the brightness of the lens. When the focal distance of the lens becomes shorter and
the diameter increases, the NA becomes bigger. It is determined using the following formul:
4.Longer Track, Smaller Pit
650nm 650nm
NA = f
a
aDisk
f
Laser Beam Focus
0.74 Track Width
Minimum Pit
0.4

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DVD-Series
5.Thinner Disc
Decreasingthethicknessofadisccancauselessfocusmovementagainstsimilardiscinclination
and less focus disorder.
6.Realization of Long Hour Reproduction
Even by making the track longer and the pit smaller to expand capacity, it is not possible to
record one whole movie on one side (1 layer) of a 12cm DVD disc if using current image data
information. To reproduce 133 minutes on a 1 layer on 1 side disc, it is necessary to digitally
compress the image data.
Most digital compression technology of data is done is the audio field.
It is already routinely used in personal computers and MD.
To make comparisons with the audio field, digital compression technology for images, which
contain far more information, were processed by the MPEG (Moving Picture Image Coding
Expert Group) committee of ISO, and became the world standard.
First,MPEG1(afixedbitratesystem)wasstandardizedandmadepracticalforuseinvideoCDs
(karaoke, etc.).
Then,MPEG2,DVD actualization, becamestandardized. MPEG2iscalled “Variable BitRate
System”.
Itcompresses informationwhilechanging theamountof data,dependingon theamountof data
on the image. That means, it compares the former and latter images, then records the amount
of change as data.
2-4 Realization of High Quality Images
1.HighQualityImagingandResolvingRatethroughFullDigitalization
The image performance of DVD actualizes 500 horizontal lines of resolution, an increase from
traditional recording media.
Currently,itissuperiortothe“themediawiththehighestqualityimage”,anLD(430horizontal
lines of resolution). It matches master tapes made to professional specifications.
With its high quality imaging and high number of resolution lines, image outlines are sharp.
Even in dark scenes, there is less noise and clearer perspective.
●Compared with to horizontal lines of resolition / recording system of DVD and traditional media
Object Lens
Laser Beam Focus
Horizontal Lines of Resolution |
Recording System s
500
DVD
Digital (MPEG2)
400 / 240
S-VHS Video Tape
/VHS Video Tape
Analogue
430
LD
Analogue
240
VideoCD
Digital (MPEG1)

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DVD-Series
●DVD responds to wide sized screens
From the beginning of its development, DVD was meant to be applicable for wide sizes.
When zoom reproduced (expanding the mage in vertical and horizontal directions) on a
wide screen monitor, the picture quality isn’t weakened. Instead, a beautiful and delicate
image is reproduced.
[Full Mode] [Zoom Mode]
2-5 Super Digital SoundThat Surpasses CDs
1.144dB Dynamic Range can be recorded
To use its large capacity equivalent to 7 times the time available on a CD in an effective way,
the96kHz/24bithighsampling/highbitcanrecord adynamicrangeof144dBsuperhi-fidigital
audio. It also reproduces sounds beyond the range of human hearing, restoring subtle nuance
to original sounds.
▲This DVD reproduced by wide TV.
It realize of high quality images. ▲This video reproduced by wide TV. But, it worries about weakness of
picture of quality.
*This picture is image illustration
for identification effects.
146MB
(24bit)
96dB
(16bit)
DVD Range
20kHz 40kHz
Natural Sound
An example of a dynamic range comparison on DVD and CD
Dynamic Range
Wavelength Band Range
2.Sound Equivalent to MovieTheaters
DVD adopts Dolby AC-3, 5.1ch.
In addition to the 4 channels on front, back, right and left, a center channel used mainly for
dialogue and a heavy lower sound are included, to make 5.1 channels.
With these, fully digital sound can be recorded and reproduced with this unit.2-6
2-6 Various Advanced Functions of DVD
These functions are able to be included on DVD discs, and the content is decided on the disc side.
Therefore, there are various contents available, depending on the DVD disc used. Only included
functions can be reproduced by remote control operation.

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DVD-Series
1.Multi-Language Response
(1) Sound Selection
DVD Video contains a maximum of 8 sound streams. They flow together like traffic a
digital signal road. Do not confuse this with “8 channels”.
Including the original language, a maximum of 8 different languages can be recorded.
Additionally, Dolby AC-3, 5.1ch can be included on all 8 streams.
For example, it is possible to put English sound 5.1ch on the first, French sound 5.1ch on
the second and non-compressed linear PCM on the third stream.
However, it requires an amount of data, so the recording time of images will be shortened.
Tomaketheimagerecordingtimelonger,thereareoptions,suchasoccupyinglessstreams,
and using 2 Dolby AC-3 channels instead of non-compressed linear PCM.
(2) Subtitle Selection
Using the maximum 32 channel sub-image, DVD can process subtitles in a maximum of
32 languages.
Each language can be individually recorded on each channel, such as Japanese, English,
French, etc.
2.Special Mode
(1) Multi-Angle Function
A maximum of 9 image angles from a concert,
sporting event, drama, etc. can be recorded with a
multiple numbers of cameras. When the event is
recorded in such way on a DVD disc, you can
choose the angle that you want to see.
(2) Parental Lock
With the multi-story application, functions that can
preventyoungerviewersfromseeingsexorviolent
scenes that parents don’t want their children to
watch include the following:
1Cutting the scene
2Replace the scene with a prepared safe scene
3Disc unable to be reproduced
* Locking function are set with the locking level
* Therearea maximumof9 lockinglevels. These
levels determined and set following the laws of
the country where the product is being sold.
* DVDdiscwillsetacertainlocklevelbeforehand
when scenes that parents do not want their chil-
dren to watch are recorded.
* When a lock level is set on an a DVD video
player, scenes or discs that violate that level
cannot be reproduced

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DVD-Series
(3) Multi-Story Function
If there are a number of subplots or side stories to a show, you can change its flow by
choosingstory developmentsbeforehand,or bypullingthe menuateach divergenceinthe
story to choose your favorite stories.
A. Main story and side story function
By selecting stories, it is possible to reproduce not only the main story but a sub story
that develops as a supporting role, just by choosing one.
B. Multi-Version Function
It is possible to edit and reproduce a mixture of different versions, such as a theater
version, a complete version and a director’s cut version, without causing any breaks in
the story.
C. Highlighted Scene Scanning Function
Scenes of your favorite actors/actresses, musicals and so on can be reproduced without
causing any breaks in the story.
[Main Story and Subplots]
D. Branching Story Function (Simple Interactive Function)
Asif itwerearole playinggame,it ispossibleto developthestory inaninteractiveway.
For example, in a drama, you can choose the characters’ next action from the menu list
one after another to create a different story and/or a different ending.
[Branching Story]

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DVD-Series
(4) How to Reproduce a Multi-Story
These multi-stories can be reproduced only on discs with the recordings of a multiple
number of stories that respond to each specification.
DVDdiscs respondtoeachsituation’s specification. Itsrecordedcontent andmethodsare
determined by what is on the disc. Therefore, it is possible
thatdiscswithvariouscontentswillbesoldonthemarket. Becauseofthisfactor,wecannot
now explain certain operating methods.
The following are the expected reproduction methods for multi-stories
1Packaging of a DVD disc that contains a reproduction method
2Choosing actions through the menu
3Operation methods that will be shown every time they are needed, and having the
viewer follows the direction(s)
3.Multi Aspect Function
With its multi-aspect function, DVD discs can be used with any type of TV.
The“Squeeze System”,thatcompresses widepictureintothestandard 4:3ratio,willreproduce
thepictureinfullhorizontallengthonawidescreenTV,sothereisnodeteriorationinthepicture
quality. Forbigimage projectorsandnormalTVs(4:3),ahighqualitypicturecanbereproduced
with the letter box, which shrinks vertical direction, or by pan & scan, which shows a 4:3 ratio
picture while cutting out the rest of the original image.
Amajorityoftraditional“widesizedpictures”havebeenshownwithblackpartsacrossthetop
andbottomof4:3ratioscreens. Therefore,whentheseareprojectedonwidescreenedTV,they
are widened by magnifying the picture until the black part disappears.
In such a case, the lines of resolution on the black parts were removed, reducing the lines from
425 to 360. That causes inferior picture quality.
However, “Squeeze Recording System” enables wide screen picture
reproduction that does not sacrifice any of the lines of resolution.
*However, it is entrusted to the production section of the DVD disc to choose which system
touseand whether the DVDisavailablefor letter box, panandscan. Pleasenote that allDVD
discs can do this function.
●Multi Aspect Functions
Wide Picture
Disc
Squeezed Recording
Direct Output
Wide Screen TV (Full Mode)
4:3 TV
Letter Box Conversion Pan and Scan Conversion
Conversion Output
DVD Player

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DVD-Series
3. Technical Point of DVDs
3-1 Disc Reproduction
1.Type of discs that DVD video player can reproduce
DVD video players are exclusively for reproduction, including music CDs.
DVD video discs with the following marks and music CDs are capable of being reproduced.
Mark (logo) Content Size of Disc Maximum
One side of the disc
12cm for approx. 4 hours
Two side of the disc
DVD Video Disc Audio + Visual for approx. 8 hours
(animation) One side of the disc
8cm for approx. 80 minutes
Two side of the disc
for approx. 160 minutes
12cm 74 min.
Music CD Audio 8cm 20 min.
(CD Single)
Video CD Audio + Visual 12cm 74 min.
No discs other than those listed above can be reproduced.
This player matches the NTSC TV system. Discs shown with other TV systems (PAL, SECAM)
cannot be used.
2.Authorization of DVDVideo Disc (local code)
Local codes are established in different countries around the world, including Japan, U.S.A./
Canada, Asia and Europe.
Some DVD video disc have established local codes. This is the result of software production
salestactics. They makeDVDvideo discs,especiallyfor newmoviesand songs,andindustrial
use discs, that are to be reproduced only in official sales areas. Therefore, it is possible to see
a message such that says “this disc cannot be reproduced due to the differences in local codes”
when one buys a DVD video disc outside of his/her country and try to play it or industrial use
videos at home.
3.Copyright Protection
To protect copyright, it is prohibited to copy, broadcast, publicly show, broadcast over a cable
system, show at public lectures, or rent (whether or not charging for it) a disc. On DVD video
players, copied picture won’t project as clear an image if it has been copied from another video
deck.
VIDEO CD

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DVD-Series
4.The Expanding DVD World
Inconvertingmusicanddataimagesintoaunifiedfileformat,theborderbetweenTVandaudio
orcomputerisremoved. Asaresult,DVDdiscshavemanypossibleusages,includingpersonal
computer reproduction of DVD software and the playing of traditional audio CDs on the DVD
player due to the compatibility of the hardware.
3-2 Title, Chapter,Track
DVD video discs are divided into big ends called “titles” and small ends called “chapters”. Music
CDs are divided into “tracks”.
Example : For a DVD Video Disc
CD
Audio CD
Public Equipment (TV environment) Computer Application
CD-ROM
DVD-ROM
DVD-Rewritable
DVD
DVD Video Disc
Music CD
Title 1 Title 2
Chapter 1 Chapter 2 Chapter 1 Chapter 2 Chapter 3
Track 1 Track 2 Track 3 Track 4 Track 5
~~~~~
Example: For a Music CD
Title : AsectionoftheDVDcontent divided into large parts. They correspond to the “story”
part of a collection of short stories.
Chapter : SectionsoftheTitle’scontentsaredividedintosmallerparts,suchasscenesandtunes.
It corresponds to the “chapter” of a book.
Track : A section made up of one song in a music CD.
Each title, chapter and track are numbered in order. These numbers are also called “Title
Numbers”, “Chapter Numbers” and “Track Numbers”.
Some discs may not have each number recorded.

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DVD-Series
3-3 Moving Image Digital CompressionTechnology MPEG2
Enables Long Hour Reproduction
Even though the recording capacity of DVD discs is 7 times more than a CD, if a TV image on
NTSC is digitally transferred and recorded, even the DVD disc can record only 4 minutes.
Research of the technology to record more information in a limited recording capacity (data
compression) started in the 1960s. The progression has went from JPEG, MPEG1 to MPEG2.
MPEG1, which was adopted for Video CDs (karaoke, etc.), can record a maximum of 74 minutes
of moving images by compressing the data to 1/100, but the picture quality is inferior to LDs.
MPEG2 offers a high quality picture by compressing the information to approximately 1/40,
addingnewtechnologytoMPEG1andincreasingthecompressionrate. Diversifiedimprovements
includechangesinthedatatransferrate(variable),framerate(double)andpredictingprimenumbers
on corresponding pictures (double) between frames and field DCT.
Comparison of MPEG2 and MPEG1 pictures
Picture compression system MPEG2(DVD) MPEG1(Video CD)
(adopted equipment)
Main picture degree 720 x 480 720 x 480
of resolution picture pixels picture pixels
Frame Rate
Data transfer speed 1~10Mbit/sec. (variable) 1.15Mbit/sec. (fix)
Average compression rate Approximately 1/40 Approximately 1/100
Picture quality More than LD About the same as VHS
*MPEG = Moving Picture Experts Group
This is the title of the compression technology working group, which is a part of the ISO/IEC
Joint Technology Committee, which in turn is part of the substructure of ISO and IEC.
1. Basic idea of MPEG 2
MPEG2 commands technological skill related to compression, which is comprised of about 20
items.
It increases the amount of information not only when complicated or fast moving pictures are
running (about 10Mbps),
but when slow or almost still pictures are running, it dramatically decreases the amount of
information (about 1Mbps).
Overall, it attains a high quality picture with a data transfer rate of average 3.5Mbps.
1/60sec.
60 pictures per 1 second
1/30sec.
30 pictures per 1 second

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DVD-Series
2. Compression Method of Moving Pictures
When you see a TV picture, you think of it as a sequentially moving picture, thanks to the
afterimage effect that “fools” our eyes. But in reality, what you are watching is a series of still
pictures that move sequentially and change at a steady rate.
Therefore, it recognizes monotonous and complicated parts on still picture frames (spatial
information). Than,itdecreasestheamountofdata(highercompression)formonotonousparts
and increases the amount of data (lower compression) for complicated parts.
Also,sincemovingpicturesareasuccessionofstillpictures,thesystemcompareseachpicture
totheonesbeforeitandmemorizesupcomingonesin order to detect how much current picture
moved. It then records only the moving part or parts (time information) as data. Reproduction
is done in reverse (encode) in order to replace data (decode).
3.Steps in Spatial Information Compression (Still Picture)
(1) DCT (Discrete Cosine Transformation)
The picture is divided into small micro blocks. Each block is again divided into smaller
blocks. (See the drawing below.)
Then, the complication of each picture is detected on each block, converting it into DCT
= frequency, in order to sort monotonous parts (unnecessary information) from compli-
cated parts (necessary information) by numeric value.
22 macro blocks
12
8
8
3
16
16
4
15 macro blocks
1 picture macro block
Macro block
Block
(2) Quantization
Thedata convertedintonumericvalue(frequency) byDCT willbemorecompressedin its
flat parts, where more information stays, by dividing it by a common value to make it
quantitated.
A This part is even,
so it is easily compressed. B This part is complicated,
so it is difficult to compress.

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DVD-Series
(3) Coding
To record the quantitated numeric values more efficiently, they will be coded.
To make coding easier, the quantitated value of macro blocks will be scanned
in a zigzag pattern or alternately.
1Ranlength Coding
Because there are a multitude of zeros (unnecessary information) in quantitated value,
it does not show all the zeros. What it shows, for example, is “six 0s” when there are 6
consecutive zeros.
2Valuable length coding
Code is shown in binary numbers. Frequently showing numbers gets the shortest code,
andrarelyappearingnumbers get longer codeinordertodecrease the overall amountof
data.
4.Steps forTime Information Compression (Moving Picture)
Compression of moving pictures is done the same it is for still pictures.
Pictures are divided in macro blocks, and the movement changes on each block is “detected”,
“predicted”and“corrected”.Also,assumingtherearemanyoccasionswhenentirepictureswill
bereplacedbydifferentones,non-compressedoriginalpictures(Ipicture)andlesscompressed
pictures (P picture) are inserted in frames at regular intervals. The pictures between them will
be inserted between these frames by predicting former and latter I and P pictures.
(1) Inserting original pictures between frame assumption
When an entire picture changes (random search, etc.), “detection”, “prediction” and
“correction” of the movement cannot be made.
Therefore, original pictures (intra = I picture) are inserted at intervals of every 6 to 15
frames and predicted pictures (P picture) from I picture every 2 to 6 frames.
Also, mutually predicted pictures among the I and P picture (bi-directionally = B picture)
are inserted between these I and P pictures.
B pictures (frames) on 1 ~ 2 below are predicted and made from I picture (frames) and P
pictures on 0 and 3.
0123456141516
B picture
intra
I picture intra I picture
Closeness to the
original picture P Closeness to the original picture P
B picture B picture
Example: Inserting I every 16 frames and P in every 3 frames.

18
DVD-Series
(2) Movement [Detection]
The system detects each macro block and compares the current picture to the past
memorizedones,andcompilesdataaboutthe directionanddistanceofmovementvectors.
123434
5
*
6
****
Macro block
Past picture (frame) Current picture (frame)
Amount of movement
Itdetectswhichsquare (block) corresponds tothisoneinthe previous picture andmeasuresthe
moved amount and directional vectors.
(3) Movement Compensation Prediction
There are parts similar in previous and successive pictures. Therefore, it is not necessary
totransfereverybitofinformationonthecurrentpicture,sincesimilarpartsoftheprevious
picture can be used.
Todeterminewhatcontentofthe current picture is to be transferred, prediction ismadeby
comparingtheamountanddirectionofmovementinthepreviouslymemorizedpictureand
the current one.
Then, only the parts with margin of error, meaning the parts that changed and/or were
added, are recorded.
Past picture (frame) called f
rom the memory
Past picture, which movement
compensation is made from
movement [detected]
Sending only the unpredicted
information
Current picture (frame)
Movement
compensation

19
DVD-Series
3-4 8/16 Modulation
When the part without a pit continues to track a disc, it becomes difficult to create a laser spot to
follow based on a pit. Also, it is difficult to judge how many 0s and 1s are being followed.
Therefore, it is necessary to limit the length of the part without a pit on the track. That means, it
is necessary to limit the succession of 0s and 1s.
8/16 modulation converts the original 8 bit data into 16 bit to limit the succession of “0s” or “1s”
from 3 to 11. Also, NRZI modulation makes both of the pit edges a “1”. With this, code reading
and recording density accuracy increases. (See below)
0011010001
Before conversion
After conversion

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DVD-Series
4. DVD Servo Circulation
4-1 Outline of Disc Servo
Spindle Motor
CLV Error Signal
Driver
Thread Motor
Focus Drive Signal
Tracking Drive Signal
Thread Drive Signal
FES
(Focus Error Signal) TES (Tracking Error Signal)
OL (Object Lens)
PU (Pick up)
RF Signal
(A, B, C & D) AGC
PLL
RF Amplifier
and
Error Formation EQ Slice
.
Asymmetrical
Revision
Servo IC
(Gain Revision, Phase Compensation)
1.Focus Servo
●Move OL up and down to focus on the disc pit.
●Disc (DVD) face shake ±300µm
Accuracy of Turn Table 150µm p-p _Suppression under ±0.23µm
2.Tracking Servo
●Move the Object Lens between the internal and external circumference (at a right-angle to
the track) to place the beam on the track.
●Disc (DVD) core 100µm p-p
Core at TT, fastened 50µm p-p _Suppression under ±0.022µm
3.Thread Servo
●Becausetheobjectlens’movementissmall(about±0.35m/minthetrackingdirection),the
entire pick-up is moved near the target track with the thread motor.
●In normal reproduction, it is necessary to make a fine movement, in which the object lens
stays around a free neutral point. In this case, it is necessary to make a high-speed move in
order to suppress object lens vibration.