IT6501- GRAPHICS AND MULTIMEDIA

III YEAR / V SEMESTER

UNIT IV

PREPARED BY,

Mr.M.KARTHIKEYAN, M.E., AP / IT

VERIFIED BY

HOD PRINCIPAL CEO/CORRESPONDENT

SENGUNTHAR COLLEGE OF ENGINEERING,TIRUCHENGODE – 637 205.

DEPARTMENT OF INFORMATION TECHNOLOGY

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UNIT IVMULTIMEDIA FILE HANDLING

Compression and decompression Data and file format standards Multimedia I/O technologies Digital voice and audio Video image and animation Full motion video

Storage and retrieval technologies.

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LIST OF IMPORTANT QUESTIONSUNIT IV

MULTIMEDIA FILE HANDLING

PART – A1. Compute the storage space in MB required storing a video of VGA resolution, true color and

30 fps, compressed at 30:1.2. State the resolution of Facsimile, Document Images and Photographic Images? 3. What is the compression technique used in Facsimile and Document Images? 4. Explain about Voice Synthesis? 5. What is Isochronous Playback? 6. Explain about Full motion and Live video? 7. Write a brief note on Fractals.8. Explain Fractal Compression? 9. Define Compression Efficiency? 10.What is Image Processing? 11.Explain Image Calibration? 12.What is Grayscale Normalization? 13.What is the need for Compression? 14.State the two types of Compression? 15.What is Lossy Compression? 16.What is Lossless Compression? 17.What are the advantages of Compression? 18.State the types of Lossy Compression? 19.State the types of Lossless Compression? 20.What is Codec? 21.State the Applications of WORM? 22.What is a Juke Box?

PART –B

1. Why compression/decompression is an essential module in multimedia file handling.Explain

the various techniques.(16) (NOV/DEC 2012) (MAY/JUN 2007)

2. Explain in detail about the Overview of data and file format standards.

3. Elaborate on various multimedia I/O technologies. Give examples.(16)(MAY/JUN 2013)

4. In detail,explain the various technologies involved in storage and retrieval of multimedia files comprising of motion videos.Comment on the challenges in it.(16)(NOV/DEC 2012) Write a brief note on optical media and disk technologies.(08)(MAY/JUN 2012)

5. Draw and explain the TWAIN architecture.(08)(MAY/JUN 2012) Or What is TWAIN? Explain the objective and architecture of TWAIN.(16)(APR/MAY 2010)

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NOTES

UNIT IV

MULTIMEDIA FILE HANDLINGPART – A

1. Compute the storage space in MB required storing a video of VGA resolution, true color and 30 fps, compressed at 30:1.The storage space required for storing a video of VGA resolution and 30 fps when it is

compressed at 30:1 is 30MB.

2. State the resolution of Facsimile, Document Images and Photographic Images? •Facsimile -100 to 200 dpi

• Document images -300 dpi (dots/pixels per inch)

• Photographic images -600 dpi

3. What is the compression technique used in Facsimile and Document Images? •Facsimile - CCITT Group3

•Document Images - CCITT Group4

4. Explain about Voice Synthesis? This approach breaks down the message completely to a canonical form based on

phonetics. It is used for presenting the results of an action to the user in a synthesized voice.

It is used in Patient Monitoring System in a Surgical Theatre.

5. What is Isochronous Playback? Isochronous playback is defined as a playback at a constant rate. Audio and Video

systems require isochronous playback.

6. Explain about Full motion and Live video? Full motion video refers to prestored video clip. i.e., video stored in CD

Eg: games, courseware, training manuals, MM online manuals etc Live video refers to live

telecast.

It is live and must be processed while the camera is capturing it i.e., Instant occurring is

transferred at the same time.

Eg: Live Cricket Show (in television)

7. Write a brief note on Fractals.

Fractals are regular objects with a high degree of irregular shapes. It is a lossy

compression technique but it doesn’t change the shape of the image. Fractals are

decompressed images that result from a compression format 4

8. Explain Fractal Compression? Fractal Compression is based on image content i.e., it is based on similarity of patterns

within an image. The steps in Fractal compression are

• a digitized image is broken into segments

• the individual segments are checked against a library of fractals

• the library contains a compact set of numbers called iterated function system codes.

• these system codes will reproduce the corresponding fractal

9. Define Compression Efficiency?

Compression Efficiency is defined as the ratio in bytes of an uncompressed image to the

same image after compression.

10.What is Image Processing? Image Processing refers to processing a digital image using a digital computer.

An image processing system will alter the contents of the image.

It involves Image Recognition, Image Enhancement, Image Synthesis and Image

Reconstruction.

11.Explain Image Calibration? The overall image density is calibrated. In Image calibration the image pixels are adjusted to

a predefined level.

12.What is Grayscale Normalization? The overall grayscale of an image or picture is evaluated to determine if it is skewed in one

direction and if it needs correction.

13.What is the need for Compression? To manage large multimedia data objects efficiently Reduce file size for storage of objects

Compression eliminate redundancies in the pattern of data .

14.State the two types of Compression? Lossy Compression

Lossless Compression

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15.What is Lossy Compression? Lossy compression causes some information to be lost. Even if some data is lost it does not

affect the originality of the image. It is used for compressing audio, greyscale or color

images and video objects in which absolute data accuracy is not essential. it is used in

Medical Screening Systems, Video teleconferencing and Multimedia Electronic messaging

systems.

16.What is Lossless Compression? Lossless compression preserves the exact image throughout the compression and

decompression process. Lossless Compression techniques are good for text data and for

repetitive images in images like binary and grey scale images.

17.What are the advantages of Compression? Compressed data object

Require less disk memory space for storage

Takes, less time for transmission over a network.

18.State the types of Lossy Compression? JPEG (Joint Photographic Experts Group)

MPEG (Moving Picture Experts Group)

Intel DVI (Digital Video Interface)

CCITT H.261(P*64)

Fractal

19.State the types of Lossless Compression? Packbits Encoding

CCITT Group3 1D

CCITT Group3 2D

CCITT Group 4

Lempel-Ziv and Welch Algorithm (LZW)

CCITT – International Consultative Committee for Telephone and Telegraph

20.What is Codec? Compression and decompression software or programs are called codec.

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21.State the Applications of WORM? Legal and Stock Trading Management

Medical Applications

Online Catalogs

Large Volume Distribution

Transaction logging

Multimedia Archival

22.What is a Juke Box? A jukebox is an optical disk device that can automatically load and unload optical

disks. The device that holds over ten to thousands of CD’s and DVD’s. It allows storage and

fast access to large amounts of data

23.State the layers of WORM drive?

Polycarbonate substrate

Recording layer is made up of A Bismuth Tellurium layer

Two layers of Antimony Solenoid

Reflective layer

Protective layer

24.How data is recorded in WORM drive?

Input signal is fed to laser diode

Laser beam strikes the three recording layers

Laser beam is absorbed by Bismuth-Tellurium layer and generates heat

The heat diffuses the atoms in the recording layers and forms a four element alloy

(Sb, Se, Bi, and Te) which is the recorded area.

25.How data is read from WORM drive?

Weak Laser beam is focused to the disk

It is not absorbed due to reduced power level and reflected back

The beam splitter mirror and lens arrangement sends the reflected beam to Photo

detector

The Photo sensor detects the beam and converts it into electrical signal

26.What is RLL?

RLL - Run-Length Limited. RLL is an encoding scheme. The benefit of RLL is that it packs

50% more bits than the MFM scheme, resulting in 26 sectors per track with a 6.4 Mbits/sec

or 798 Kbytes/sec transfer rate.

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27. Explain briefly about Rewriteable Optical Disk technology?

Rewriteable optical media technology allows erasing old data and rewriting new data over

old data. It behaves like a magnetic hard disk where data can be written and erased

repeatedly. Two types of Rewriteable technology are

Magneto-optical technology Phase change rewriteable optical disk.

28.Write short note on Magneto-optical technology?

Magneto-optical technology uses a combination of magnetic and laser technology to

achieve read/write. The disk recorded layer is magnetically recordable. It uses a weak

magnetic field to record data under high temperatures. It requires two passes to write data.

In the first pass, the magneto optical head goes through an erase cycle. In the second pass

it writes the data.

29.Explain the Phase Change technology?

In phase change technology the recording layer changes the physical characteristics from

crystalline to amorphous under the influence of heat from a laser beam. The benefits of

phase change technology are equire only one pass to write the data.

No magnetic technology is needed.

30.What is a multifunction drive?

A multifunction drive is a single drive unit. It is capable of reading and writing a variety of

disk media i.e., CD-ROMS, WORM drives and rewriteable disks. It provides permanence of

read-only device and flexibility of a rewriteable device. It is used in product documentations.

31.Explain Hierarchical storage Management?

The primary goal of hierarchial storage is to route data to lowest cost device that will support

the required performance of that object.

32.Define Cadence.

Cadence is a term used to define the regular rise and fall in the intensity of sound.

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PART –B

1. Why compression/decompression is an essential module in multimedia file handling.Explain the various techniques.(16) (NOV/DEC 2012) (MAY/JUN 2007)

Compression and Decompression

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Need for compression and decompressionA digital process that allows data to be stored or transmitted using lesser than the normal number

of bits. Compression can be lossless, lossy or visually lossless There are several types of which

the JPEG standard of lossy compression is widely used for still imaging. In general, compression

should not be used where images may be required for scientific analysis for although the data loss

may not be visually apparent, it may be essential from a scientific or legal point of view

Compressions in multimedia systems are subjected to certain constraints that are listed below:

The quality of the reproduced data should be adequate for applications

The complexity of the technique used should be minimal, to make a cost effective

compression technique

The processing of the algorithm should not take too long

Various audio rates should be supported. Thus, depending on specific system conditions the

data rates can be adjusted

It should be possible to generate data on one multimedia system and reproduce data on

another system. The compression technique should be compatible with various reproduction

systems

Need for Compression:Consider a digital video sequence at a standard definition TV picture resolution of

720×480 and a frame rate of 30 frames per second (FPS).If a picture is represented

using the RGB color space with 8 bits per component or 3bytes per pixel, size of each

frame is 720×480×3 bytes. The disk space required tostore one second of video is

720×480×3×30 = 31.1 MB.A one hour video would thus require 112 GB. To deliver

video over wired and/orwireless networks, bandwidth required is 31.1×8 = 249 Mbps.

In addition to these extremely high storage and bandwidth requirements, using

uncompressed video will add significant cost to the hardware and systems that process

digital video. Digital video compression is thus necessary even with exponentially

increasing bandwidth and storage capacities.

Fortunately, digital video has significant redundancies and eliminating or reducing

those redundancies results in compression. Video compression can be lossy or loss less.

Loss less video compression reproduces identical video after de-compression. We

primarily consider lossy compression that yields perceptually equivalent, but not identical

video compared to the uncompressed source.

Video compression is typically achieved by exploiting four types of redundancies:

1) perceptual, 2) temporal, 3) spatial, and 4) statistical redundancies.

Decompression:

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Decompression is the inverse of compression. Decompression techniques can

differ from the compression techniques in various ways.

For example, if the applications are symmetric, e.g., dialog applications, then the coding

and decoding should incur more or less the same costs, as the importance here is the

speed factor, rather than quality However, if data will be encoded once, but decoded

many times, as is the case with an image or video retrieval system, then whereas the

decoding speed must approximate real-time, the encoding time may be asymmetric to the

decoding time Usually, better quality/compression ratios are obtained if encoding time is not

a factor.

Compression standardsData compression:

As with any communication, compressed data communication only works when both

the sender and receiver of the information understand the encoding scheme. For example,

this text makes sense only if the receiver understands that it is intended to be interpreted

as characters representing the English language. Similarly, compressed data can only

be understood if the decoding method is known by the receiver.

Compression is useful because it helps reduce the consumption of expensive

resources, such as hard disk space or transmission bandwidth. On the downside,

compressed data must be decompressed to be used, and this extra processing may be

detrimental to some applications.

Non-lossy compression for photographs and videosWhen a compression algorithm is used in an applied environment, the choice of that

algorithm is often governed by the situations where the compression will take place. Good

algorithms for text compression may not be useful to compress a motion picture file,

whereas an algorithm suitable for compression of an audio file may not be a good

choice for a speech file. Obviously, speed of encoding and decoding are important, but

another factor, not yet mentioned in detail, is the question of whether, when one

uncompressed the compressed material, gets back the original. If information is lost

during the compression process, the algorithm is lossy. If the compression algorithm

guarantees the uncompressed material is what was started with, this is called non lossy

compression or lossless compression. Lossless compression technique must be used

when compressing data and programs. For greater compression of video and images

compression technique must be used.

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Lossy compression for photographs and videosA lossy compression method is one where compressing data and then

decompressing it etrieves data that is different from the original, but is close enough to be

useful in some way. Lossy compression is most commonly used to compress multimedia

data (audio, video, still images), especially in applications such as streaming media and

internet telephony. By contrast, lossless compression is required for text and data files,

such as bank records, text articles, etc. In many cases it is advantageous to make a master

lossless file which can then be used to produce compressed files for different purposes; for

example a multi-megabyte file can be used at full size to produce a full-page

advertisement in a glossy magazine, and a 10 kilobyte lossy copy made for a small

image on a web page.

The original contains a certain amount of information; there is a lower limit to the size

of file that can carry all the information. As an intuitive example, most people know that a

compressed ZIP file is smaller than the original file; but repeatedly compressing the file

will not reduce the size to nothing.

Hardware versus Software CompressionThis is performed by the drive at the drive level, hence the name 'hardware

compression'. It has an advantage in that since the compression is done by the drive,

there is no system overhead. Hardware compression is only configurable in so far as it is

either on or off, there is no way to tune or configure the rate of data compression either on

the Hardware, or using ARC serve.

Compression on most modern drives is soft set, meaning that hardware

compression can be enabled or disabled by sending a SCSI command to the drive. If your

drive supports hardware compression settable in this way, an option for compression will

be shown in ARC serve device manager, allowing you to enable or disable hardware

compression. We will look at this in more detail later on in this document. Older drive

technologies may set compression using jumper blocks or DIP switches on the drive

unit.

2. Explain in detail about the Overview of data and file format standards.Multimedia data and information must be stored in a disk file using formats

similar to image file formats. The variety of data it stores includes text, image data,

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audio and video data,computer animations, and other forms of binary data, such as

Musical Instrument Digital Interface (MIDI), control information, and graphical fonts.

The personal computer industry and, more specifically, the Microsoft-Windows-

based systems form the largest base for multimedia systems

The multimedia file formats are

Rich-text format (RTF)

Tagged image file format (TIFF)

Resource image file format (RIFF)

Musical instrument digital interface (MIDI)

Joint Photographic Experts Group (JPEG)

Audio Video Interleaved (AVI) Indeo file format

TWAIN

Rich text formatRTF is a document language used for exchanging text between different word

processors and text-processing applications. RTF is much easier to generate than PDF or

PostScript, and is more word-processor friendly than HTML. RTF has been around for over

a decade, while hundreds of other binary formats have come and gone.

Tiff File FormatBig TIFF Proposal:

The Big TIFF file format is an ongoing attempt to design a next version of TIFF,

specifically targeted at breaking the 4 gigabyte boundary. This page presents an overview

of the current proposal.

TIFF Tag Reference:

A reference on all known baseline, extended, and private TIFF tags. Includes

basic properties of each tag (such as code, name, LibTiff name and data type), as well as a

short description. Also includes a useful search function, and a means for owners of

private tags to submit data about the tags.

TIFF Tag Viewer:

As Tiff Tag Viewer is a free TIFF Tag Viewer application for Windows. It lets you view

each TIFF page's tags/fields (code, data type, count and value). As Tiff Tag Viewer is

an indispensable tool for any professional to diagnose any TIFF file. Whenever a

customer reports your software doesn't handle this or that particular TIFF, use As Tiff Tag

Viewer and discover.

TIFF Tag Reference:

This is a reference on all known baseline, extended, and private TIFF tags. Every

tag page offers a list of basic properties (such as code, name, Lib Tiff name and data

type), as well as a short description.

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Search:

Search for any specific tag or group of tags here.

Baseline Tags:

Baseline tags are those that are listed as part of the core of TIFF, the essentials that all

mainstream TIFF developers should support in their products.

Extension Tags:

Extension tags are those listed as part of TIFF features that may not be supported

by all TIFF readers.

Private Tags:

Private tags are, at least originally, allocated by Adobe for organizations that wish

to store information meaningful only to that organization in a TIFF file. The private tags

listed here are the ones that found their way into the public domain and more general

applications, and the ones that the owning organizations documented for the benefit

of the TIFF community.

Private IFD Tags:

If one needs more than 10 private tags or so, the TIFF specification suggests

that,rather than using a large amount of private tags, one should instead allocate a

single private tag, define it as data type IFD, and use it to point to a so-called 'private

IFD'. In that private IFD, one can next use whatever tags one wants. These private IFD tags

do not need to be properly registered with Adobe; they live in a namespace of their

own, private to the particular type of IFD.

3. Elaborate on various multimedia I/O technologies. Give examples.(16)(MAY/JUN 2013)Multimedia I/O Technologies

Pen Input

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The digital pen is a input device that allows the user to write, draw, point and

gesture (perform an action such as stroke and a loop). Pens have been used in CAD/CAM

system to point and select.

Use of a pen is to point, pick, drag and click on an object. A gesture is another type

of user interface for entering characters and for writing notes on the screen of pen

based system.

The Pen Extensions include a set of dynamic link libraries (DLLs) and drivers that

make applications pen-enabled. The DLLs allow pen-based input and handwriting

recognition.

The Pen Computing system consists of following components:

Electronic pen:

When an electronic pen is used to write or draw, the digitizer encodes the x and y

coordinates of the pen, and the pen status. The pen status includes whether the pen is

touching the digitizer surface (usually the screen) or not, pen pressure, pen angle, pen

rotation, and so on.

The minimum resolution defines that sufficient x-y location data is generated to maintain

the accuracy of the pen path over the digitizing surface.

Digitizer:

The most commonly used digitizers include the following two types:

A transparent digitizer bonded to the thin flat LCD screen of a notebook or palmtop

computer (PDA)

A separate tablet containing electronic digitizing circuitry, with pen or mouse. The

digitizer generates the pen position (x and y coordinates) and the pen status (distance from

the screen surface and pen contact with the screen).

Pen Driver:

A pen driver is a pen device driver that interacts with the digitizer to receive all the

digitized information about the pen location. The pen driver in the windows for Pen

system consists of two drivers:

An installable Windows pen driver and a virtual driver

Video and Image Display System

Video, like sound, is usually recorded and played as an analog signal. To incorporate

video into a multimedia application it has to be digitized. The video in a multimedia

application brings a sense of realism, engage the user and evoke emotions. The visual

technologies employed to display video makes the display system an important architectural

component in the design of any multimedia system

Display System Technologies

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While displaying images and full-motion video in windows it is required to resize the

windows dynamically to cope up with the user preferences In resizing the windows the

number of pixels being displayed would change. That is,when the windows become longer,

pixels per inch of the original rendering change Scaling down to smaller window in achieved

by dropping pixels, but scaling up to a larger window requires adding pixels that do not exist

in the originally captured image Dynamic scaling becomes much more complex if the display

window contains full motion video

The display system generates the visual output of text, graphics and video that the

end user sees. A range of video display standards with possible parameters are presented

in the table

Resolution and Dot pitch

To display an image on a monitor the scanning process takes place. Monitor screen

consists of a number of scan lines A scan line is made of a pixel array. The screen

resolution of the monitor is defined by the product of pixels per scan line and the number of

scan lines. The higher the resolution, the sharper the image.

Each pixel on the screen is made of red, green and blue (RGB) phosphors arranged

in a triad. The distance between on RGB phosphor to the next is called dot pitch smaller the

dot pitch, the finer the size of the pixel and lower the chance of pixel overlap at higher

resolution.

Horizontal and Vertical Refresh Rate, and Flicker

The rate at which the horizontal scan lines are painted horizontal scan frequency and

is measure in kilohertz. The vertical scan frequency depend on the horizontal scan

frequency The sweep starts from left to right and progress gradually to the end of the last

scan line and returns to the top of the screen.Sometimes low vertical refresh rates cause the

human eye not retain a continuous perception of successive images and is referred tom

flicker

Interlaced scan and Non-interlaced Scan Mode

It interlaced scan mode the odd lines are scanned first and then the even lines are

scanned. Hence, it takes two passes to paint or refresh one frame on the screen In non-

interlaced scan mode all lines are scanned in one pass sequentially. Hence, twice the

number of lines are painted on the screen in every pan and thus doubling of the frame

repaint rate Non-interlaced mode is the recommended one to reduce flicker for multimedia

applications using high resolution

CRT Display System

The Cathode Ray Tube (CRT) is a vacuum glass tube with the display screen at one

end and connectors to the control circuits at the other end CRT function using electrostatic

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deflection coils mounted on the outside of the glass envelope to bend the electron beam with

magnetic fields

Phosphor Types

Phosphor is a chemical compound coated on the inside surface of the picture tube. A

triad consists of a set of red green and blue phosphors arranged in a triangle When an

electron beam strikes the phosphor, it glows and generates visible color. The color of the

light and the time period vary from one type of phosphor to another The light given off by the

phosphor during exposure to the electron beam is known as fluorescence, the continuing

glow given off after the beam is removed is known as phosphorescence and the duration of

phosphorescence is known as phosphor’s persistence.

Flat Panel Display system

Color Display System like color monitors used to display millions of colors, associated

with multimedia application

The way the colors are exhibited in a color display system mainly depends on the two

parameters, already discussed, namely

1. Number of colors and

2. Resolution of the display

Further, it depends on the memory capacity of the video controller card called

VRAM.A particular combination of colors and resolution is called the video mode of the

display system Though all presentation display systems basically use the same technology,

called the Liquid Crystal Display (LCD), they are offered in various forms.

LCD Projection PanelsIn this, the output from the computer is directed to a small and compact matrix of

LCDs arranged in a specific pattern. This arrangement is kept over a projection system.

When the projection system is illuminated the graphics in the pattern corresponding to the

output from the computer is displayed, four basic technologies are used for Flat panel

displays

1. Passive matrix monochrome2. Active-matrix monochrome3. Passive-matrix color4. Active-matrix colorThe first two technologies are becoming obsolete and are used in very limited

application passive matrix color LED panel, suffer from lesser color saturation, contrast and

slower response time These are less costlier and are suitable for slide slide show

presentation and predominantly used in notebooks and PDAs

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Active matrix color LCD panels displays and long persistence and are costlier To

improve the efficiency of the LCD displays backlit or sidelit technologies are being used the

Light Emitting Diode (LED) technology. LEDs are electronic devices capable of displaying

any particular combination of RGB color and is also transparent to lights,So when a series of

these LEDs are arranged to form a row-column matrix, they can be used in place of pixels in

monitors and can display the output from the computer

This is the basic principle behind all LED projection system and LCD arranged in the

form of row-column matrix are known as LCD panels

Print Output TechnologiesLaser print technology has continued to evolve, and print quality at 600 dpi started to

make the technology useful for high-speed presses.Typical textbooks printed by offset

presses range from 1200 dpi to 1800 dpi, the 600 dpi sufficient for most industrial manuals

and maintenance books.1200 DPI printers were commonly available during 2008. 2400 DPI

electro photographic printing plate makers, essentially laser printers

that print on plastic sheets, are also available.

An important advantage of this approach is that the manuals can be upgraded very

easily, and printing of new manuals can be achieved almost instantaneously by changing the

files being printed. As compared to high-quality offset printing, where setting up a print job

can take a long time, there is literally no setup time for laser print output. Laser printing

technology is the most common technology for multimedia systems.

Laser Printing Technology

Print technologies have enhancements in the form of speed, resolution, dot size (for

greater clarity at higher resolutions), gray-scale printing, and color printing.These ongoing

enhancements are aimed at achieving the same level of quality and control obtained from an

offset press.

The basic components of the laser printer are:

Paper feed mechanism

Paper guide

Laser assembly

Corona assembly

Fuser

Toner cartridge

The paper feed mechanism moves the paper from a paper tray through the paper

path in the printer. The paper passes over a set of corona wires that induce a charge in

the paper.

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The charged paper passes over a drum coated with fine-grain carbon (toner), and the

toner attaches itself to the paper as a thin film of carbon. The paper is then struck by a

scanning laser beam that follows the pattern of the text or graphics to be printed.

Dye Sublimation Printer

A dye sublimation printer, has a thermal printing head with thousands of very tiny

heating elements, plastic film transfer roll mounted on two rollers and a drum The

transfer roll film contains panels of cyan, magenta, yellow and black eyes.

During printing, individual heating elements can be heated to one of 256 different

temperature levels. The coils are heated to their individual temperature levels under program

control.

The cyan panel is rolled under the thermal printing head first. Tiny spots of cyan dye

from the panel get printer paper, which clings to the drum. The printer paper is coated with

polyester to help absorb the dye quickly. The hotter the temperature of the heating element,

the greater the dye vaporized resulting in a denser and larger dot.

The dye sublimation printer is very applicable to multimedia applications because it

prints in color, and the print quality is very high.

Graphic artists, advertising agencies, the film industry, whoever requires photographic

quality prints with continuous tone can use the printer.

Image ScannersScanners are quite popular for capturing images from hardcopy sources such as

books, magazines, letters, photographs and even camera slides. Scanners operate in similar

fashion to photocopier in that images are electronically captured with an array of light

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sensors. The sensors convert light into color and light intensity one line at a time until the

complete document is viewed.

Types of Scanners

Flat-Bed Scanners

Rotary Drum Scanners

Handheld Scanners

Flat-Bed Scanners:

Flat-bed scanners are best suited for larger documents as well as books and other

odd-shaped source images.The scanning bed in the scanner, a glass plate, is utilized to

place a document for scanning.

A light source, a fluorescent lamp, is mounted on a traction mechanism which moves

from one end of the document to the other end during a scan session. Flatbed scanners are

the workhorses of document image scanning. For heavy-duty scanning operations, flatbed

scanners are fitted with sheet-feeding mechanisms that allow as many as 200 sheets to be

stacked. Typical scanning speeds range from 8 pages / minute to 30 pages / minute.

Rotary Drum Scanners:

A rotary drum scanner contains a drum in the paper transport system. It contains

feeder and stacking trays, and electronics interfaces. It addition to the feeder and stacking

trays, the scanner contains two sets of belts and three sets of roller guides to guide the

paper.The paper is fed from the feed tray and is clinched by the transport mechanism and

wrapped around the drum. The front side of the page is scanned in position 1 as it rolls

around the drum, and the back side of the page is scanned in position 2 as the transport

mechanism pulls the paper from the drum and ejects it out to the stacking tray.

Handheld Scanners:

Handheld scanners are used for casual use to capture a part of a page from a book, a

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manual, or newspapers. It can scan over an area as large as 8.5-inch x 50-inch withsensitive

color image sensor that scans at high 600dpi or standard 300dpi.Handheld scanners are

useful where the document cannot be placed on a flatbed scanner or for the convenience of

carrying a small light scanner.

Handheld scanners offer portability and the convenience of a simple device at a cost

lower than that of a flatbed scanner. There are some problems associated with handheld

scanners. A very steady hand is necessary to guide the scanning motion to avoid skewing,

poor registration, and improper alignment. Handheld scanners use a light bulb as a light

source to illuminate the scan line being scanned. The light is reflected from the document as

the user moves the scanner across the document.

A fixed CCD array absorbs the reflected light and generates analog voltage, which in turn

gets converted to a digital value.

Digital Voice and AudioAudio is any sound output from a source. Digital audio is that, the audio signal

converted into 0s and 1s. Digital audio systems are designed to make use of the range of

human hearing frequency 20Hz to 20 KHz.

The quality of digital audio is characterized by the sampling rate, the sampling

resolution and the number of channels. The sampling rate determines the frequency

response of a digital audio system.

Frequency response refers to the range of frequencies that a medium can reproduce

accurately. The sampling resolution is the number of bits per sample. This determines the

dynamic range which describes the spectrum of the softest to the loudest sound amplitude

levels that a medium can reproduce.

One bit yields 6 dB of dynamic range. For example, 16-bit audio contributes 96dB of

Dynamic range found in CD-quality audio, which is nearly the dynamic range of human

hearing. Different system have different number of channels. For example, mono systems

have single channel, stereo system have two channels (left and right) and dolby surround

systems have 5.1 channels.

In this the five full range channels of audio includes three format channels (left,centre,

right and two surrounds) and a low frequency bass effect channel called the sub-woofer

which has only a limited frequency response of about 100 Hz.Hence, this sub-woofer is

sometimes referred to as the “1” channel. With the higher sampling rate, the more bits per

sample and the more channels, it renders higher quality of the digital audio. Therefore,

higher storage and bandwidth are required.

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The Table gives the description on the above Digital audio and video typically

requires specialized hardware and software for capture and playback. There are three

aspects of the digital audio video operation.

1. Capture - raw analog sources are digitized and compressed via hardware (audio and

video) or software (video).

2. Storage - files are stored and/or transmitted.

3. Playback - playback based on hardware or software digital to analog conversion.

4. In detail,explain the various technologies involved in storage and retrieval of multimedia files comprising of motion videos.Comment on the challenges in it.(16)(NOV/DEC 2012) Write a brief note on optical media and disk technologies.(08)(MAY/JUN 2012)

Optical storage demerits and latencyOptical data storage, which once appeared to be a failing technology in the

marketplace, is quickly finding its way into homes and offices with the multimedia

revolution. It has become one of the important enabling technologies fusing together the

entertainment and computing industries. Although the basic concepts for optical storage

were first proposed in the United States in the 1960s, over the last decade Japan has clearly

pulled ahead in terms of development and production.

In view of the important role optical storage is likely to play in the future, it may be

critical for the data storage and optoelectronics industries to design a catch-up strategy.

CD-ROMA CDROM (compact disk read-only memory), also written as CD-ROM, is a type of

optical storage media that allows data to be written to it only once.Storage refers to devices

or media that can retain data for relatively long periods of time (e.g., years or even decades).

This contrasts with memory, whose contents can be accessed (i.e., read and written to) at

extremely high speeds but which are retained only temporarily (i.e., while in use or only as

long as the power supply remains on).

Most storage devices and media are rewritable, including hard disk drives (HDDs),

floppy disks, USB (universal serial bus) key drives, magnetic tape and some types of optical

disks.

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CD-ROM Standards:The most popular way to organize data in CD-ROMs is according to the ISO 9660 standard.

ISO 9660 specifies a very minimal file system, which is even simpler than the one used by

MS-DOS.

This has the advantage of making it compatible with almost every operating system.

Additional benefits, including longer filenames and symbolic links, are provided by the Rock

Ridge extension.

The standard CDROM holds 650 or 700 megabytes (MB) of data, which, when

compressed, is comparable to the data than can be accommodated in printed books

occupying several hundred feet of shelf space. This, together with their low cost of

production, light weight (less than 30 grams) and durability, makes CD-ROMs a popular

means of distribution of software and storage of data.

DVDs (digital video disks or digital versatile disks) typically have a capacity at least 4.4 GB

of data, roughly seven times the amount of CD-ROMs.

DVD technology is similar to CD technology except that a higher precision laser is used,

which makes possible a higher recording density. As is the case with CDs, there are

rewritable DVDs and DVDs that can be written to only once (i.e., DVD-ROMs).

Mini Disk (MD)Identification:

A mini disc itself is 2.5 inches in diameter and is encased in a hard plastic shell,

giving it a similar appearance to a computer floppy disc.

Function:

Once inserted into an MD player, a disc can record off of a microphone or other audio

player through a stereo coaxial connection. The recorded tracks can be labeled, move to

different positions on the disc or erased.

Time Frame:

A mini disc contains between 70 and 80 minutes worth of audio disc space, which can

be separated into as many tracks as desired.

History:

The mini disc was first released by Sony Electronics in 1992. Other manufacturers

like Maxell and TDK have since produced their own discs.

Effects:

Mini discs can often be connected to computers through a player's USB connection

and then share MP3 files. The computer will need driver software from the player's

manufacturer.

Potential:

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Mini discs have not had mainstream popularity in Europe or America. However, they

have found a niche in portable live field recordings.

WORM Optical DrivesA storage medium from which data is read and to which it is written by lasers. Optical

disks can store much more data -- up to 6 gigabytes (6 billion bytes) -- than most portable

magnetic media, such as floppies.

There are three basic types of optical disks:

CD-ROM: Like audio CDs, CD-ROMs come with data already encoded onto them.

The data is permanent and can be read any number of times, but CD-ROMs cannot be

modified.

WORM: Stands for write-once, read -many. With a WORM disk drive, you can write data

onto a WORM disk, but only once. After that, the WORM disk behaves just like a

CD-ROM.

Erasable: Optical disks that can be erased and loaded with new data, just like magnetic

disks. These are often referred to as EO (erasable optical) disks. These three technologies

are not compatible with one another; each requires a different type of disk drive and

disk.Even within one category, there are many competing formats, although CD-ROMs are

relatively standardized.

Rewritable Optical Disk TechnologiesThe two mainstream technologies for rewritable optical data storage are based on

magneto-optical (MO) and phase-change (PC) media. In both cases a focused laser beam is

used to raise the temperature of the medium beyond a certain critical temperature (i.e.,

melting and crystallization temperatures in the case of PC, and the Curie temperature in the

case of MO) for writing, erasure, and overwriting of data.

The readout of information from these media relies on the change of reflectivity of the

medium (PC), or the effect of the medium on the state of polarization of the laser

beam (MO).

The performance of these data storage systems is characterized by the storage

density of the media, achievable data rates during recording and readout, longevity,

reliability, and cost of the finished products.

Magneto-optical Technology:

As implied by the name, these drives use a hybrid of magnetic and optical

technologies, employing laser to read data on the disk, while additionally needing magnetic

field to write data. An MO disk drive is so designed that an inserted disk will be exposed to a

magnet on the label side and to the light (laser beam) on the opposite side. The disks, which

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come in 3.5in and 5.25in formats, have a special alloy layer that has the property of

reflecting laser light at slightly different angles depending on which way it's magnetized, and

data can be stored on it as north and south magnetic spots, just like on a hard disk. While a

hard disk can be magnetized at any temperature, the magnetic coating used on MO media is

designed to be extremely stable at room temperature, making the data unchangeable unless

the disc is heated to above a temperature level called the Curie point, usually around 200

degrees centigrade. Instead of heating the whole disc, MO drives use a laser to target and

heat specific regions of magnetic particles. This accurate technique enables MO media to

pack in a lot more information than other magnetic devices. Once heated the magnetic

particles can easily have their direction changed by a magnetic field generated by the

read/write head.

Phase Change Rewriteable Optical Disk:A type of rewritable optical disk that employs the phase change recording method.

Using this technique, the disk drive writes data with a laser that changes spots on the disk

between amorphous and crystalline states.

An optical head reads data by detecting the difference in reflected light from

amorphous and crystalline spots.

A medium-intensity pulse can then restore the original crystalline structure.

Magneto-optical and dye-polymer technologies offer similar capabilities for developing re-

writable optical disks.

Multifunction Drives:The emergence of optical disk storage technology with high density and long lifetime

is a great event in information science and technology. Nowadays the high storage density

optical disks are the key devices for data storage at the dawn of a full-scale multimedia age.

The new storage media are still the bottleneck in high density optical storage. It is an

important task to search for new optical recording media with high performance and to

explore new preparation approaches to obtain high quality recording films. A series of

organic materials for optical storage have been studied for a long time, but only a few of

them have obtained practical application. For example, some cyanine and phthalocyanine

dyes have been used in recordable compact disks (CD-R). For erasable (or rewritable)

disks, the most applicable storage media are inorganic materials, such as magneto-optical

and phase change materials.

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Multifunction DrivesHierarchical Storage Management

Hierarchical Storage Management (HSM) is a data storage technique which

automatically moves data between high-cost and low-cost storage media. HSM systems

exist because high-speed storage devices, such as hard disk drive arrays, are more

expensive (per byte stored) than slower devices, such as optical discs and magnetic tape

drives. While it would be ideal to have all data available on high-speed devices all the time,

this is prohibitively expensive for many organizations. Instead, HSM systems store the bulk

of the enterprise's data on slower devices, and then copy data to faster disk drives when

needed. In effect, HSM turns the fast disk drives into caches for the slower mass storage

devices.The HSM system monitors the way data is used and makes best guesses as to

which data can safely be moved to slower devices and which data should stay on the fast

devices.

Permanent vs. Transient Storage Issues:There are endless threads on this (which admittedly are hard to find by searching) but

the general consensus AFAIK is that HDDs (with redundancy) are the most convenient and

reliable solution, followed by DVD-Rs (CD-R capacity is too low to be of much use these

days of RAW and high-MP images). As long as you spin a hard drive up every month or so

(which is probably not a problem if it's a backup device) and have a secondary backup

(because HDDs do go bad every now and then) you should be fine. I'd also avoid portable

HDDs and get a standard 3.5" drive in an external enclosure -- much more reliable and if the

power supply or plugs go bad you simply swap the drive into a new enclosure (for $20). The

problem with DVD-Rs is that they need good storage conditions and even then they can go

bad with no warning. Recovering data from a rotten DVD is next to impossible.

Online storage is too unreliable IMO (there have been instances of online storage

companies going under), ZIP drives are/were hopelessly unreliable, and the jury is still

out on flash-memory based storage -- CF and SD cards are probably too delicate,but SSDs

could turn out to be a better bet for long-term storage.

Optical Disk Library (Jukebox):Also called an "optical jukebox," it is an optical disk storage system that houses

multiple disc platters.It is similar to a music jukebox, except that instead of "playing one

tune," more than one drive can be used to read and write several discs simultaneously. Such

devices are made for rewritable optical discs, write once discs and CD-ROMs, and can

hold from a handful to several thousand discs or cartridges.

Hierarchical Storage Applications:

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Characteristics of Hierarchical Storage:Also known as tiered storage, the driving rationale for using hierarchical storage is the

notion that costs can be reduced by storing all or part of collection of files (bitstreams) on

lower performing, less expensive storage technologies while keeping a copy of some part of

the collection on a high performing, more expensive storage technology for immediate use.

There may be any number of tiers in the hierarchy but the most common

implementations consist of one or two tiers of random access disk followed by tape storage

as the lowest tier. The hierarchical storage manager implements some policy for determining

on what tier files are stored to meet system goals and moving files between tiers as dictated

by the policy. In real world implementations, many other needs may be fulfilled by

hierarchical storage such as backup, replication, high availability and disaster recovery.

However, it is cost that underlies any decision to deploy hierarchical storage. At this

time, magnetic tape provides the lowest cost in most deployment scenarios.

Cache Management for Storage SystemsA type of memory that is used in high-performance systems, inserted between the

processor and memory proper. The memory hierarchy on a system contains registers in the

processor, which are the highest-speed storage, and, at a slightly lower level of accessibility,

the contents of the main memory.

The cache is intended to reduce the discrepancy in accessibility between these two

types of unit, and functions by holding small regions that map the contents of main

memory. The formal behavior of the cache corresponds closely to that of the working set in a

paging system. Some magnetic disk controllers have a cache. The working of the cache is

not visible

to the main CPU, but again provides a mapping of the current contents of part of the disk

units in order to provide improved performance.

Low-Level Disk Caching:Disk drive capabilities and processing power are steadily increasing, and this power gives us

the possibility of using disks as data processing devices rather than merely for data

transfers. In the area of malicious code (malware) detection, anti-virus (AV) engines are slow

and have trouble correctly identifying many types of malware. Our goal is to help make

malware detection more reliable and more efficient by using the disk drive’s processor.

Using the extra processing power available on modern disk drives can provide significant

advantages in detecting malware including reducing the traditional AV engine’s workload on

the host CPU by partitioning the workload between the host AV engine and the disk drive,

improving the detection of stealth malware by providing a low-level view of the system, and

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recognizing virus behavior by observing disk I/O traffic directly. Several research questions

must be addressed before these benefits can be realized: how to correctly partition work

between the AV engine and the disk drive processor, how to design interfaces between the

operating system (OS) or host AV engine and the disk drive that provide satisfactory

performance without compromising security, and how to recognize malicious behavior based

on the dynamic analysis of low-level data accesses.

Cache Organization for Hierarchical Storage Systems:

We propose and analyze a two-level cache organization that provides high memory

bandwidth. The first-level cache is accessed directly by virtual addresses. It is small, fast,

and, without the burden of address translation, can easily be optimized to match the

processor speed. The virtually-addressed cache is backed up by a large physically-

addressed cache; this second-level cache provides a high hit ratio and greatly reduces

memory traffic. We show how the second-level cache can be easily extended to solve the

synonym problem resulting from the use of a virtually-addressed cache at the first level.

Moreover, the second-level cache can be used to shield the virtually-addressed first

level cache from irrelevant cache coherence interference. Finally, simulation results show

that this organization has a performance advantage over a hierarchy of physically-addressed

caches in a multiprocessor environment.

Cache Organization for Distributed Client-Server Systems:

With the continuing decline in the cost of computing, we have witnessed a dramatic

increase in the number of independent computer systems. These machines do not compute

in isolation, but rather are often arranged into a distributed system consisting of single-user

machines (workstations) connected by a fast local-area network (LAN).

The workstations need to share resources, often for economic reasons. In particular,

it is desirable to provide the sharing of disk files. Current network technology does not

provide sufficiently high transfer rates to allow a processor’s main memory to be shared

across the network. Management of shared resources is typically provided by a trusted

central authority. The workstations, being controlled by their users, cannot be guaranteed to

be always available or be fully trusted. The solution is to use server machines to administer

the shared resources. A file server is such a machine that makes available a large quantity

of disk storage to the client workstations. The clients have little, if any, local disk storage,

relying on the server for all long term storage. The disparity in speeds between processor

and remote disk make an effective caching scheme desirable. However, no efficient, fully

transparent solutions exist for coherence in a distributed system.

Distributed data base systems use locking protocols to provide coherent sharing of objects

between clients on a network. These mechanisms are incorporated into the systems at a

very high level, built on a non-transparent network access mechanism, and are not

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concerned with performance improvements. We prefer a solution that is integral to the

network file system, and provides the extra performance of an embedded cache. Several

distributed file systems that include some form of caching exist. The next sections present a

survey of their characteristic features.

5. Draw and explain the TWAIN architecture.(08)(MAY/JUN 2012) Or What is TWAIN? Explain the objective and architecture of TWAIN.(16)(APR/MAY 2010)

To avoid the custom interface problem ,the TWAIN working group formed an

open std interface for input device.

The std interface was designed to allow application to interface with different

types of input devices such as cameras , scanners etc and the benefits are as

follows,

Application developers can code to a single TWAIN that allows application to

interface to all TWAIN device.

Device manufactures can write device drivers for their proprietary devices and

allow the device to be used by all TWAIN complaint application.

TWAIN allows users to invoke “Acquire” and “select source” to select one of

multiple device.

TWAIN architecture

Application Layer

Protocol Layer

Acquisition Layer

Device Layer

Network

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Local device

Source Manager

User Application #1User Application #2

TWAIN CODE TWAIN CODE

Local source Remote source

Twain architecture defines set of architecture programming interface and protocol to

acquire data from input device , and it is shown in the figure.

TWAIN objectives Supports multiple platforms

Supports multiple devices

Widespread acceptance with standard interface

Standard extendibility and backward compatibility.

Application layer This set up a logical connection with device , and set guidelines for the he user inter -

face to select the source from a given list of logical devices.#

It also specifies user interface guidelines to acquire data from the selected sources.

Protocol layer The protocol layer is responsible for communication between the application and ac-

quisition layer.

It specifies the services provided by sources, establishing a session, physical connec-

tion to device

Source Manager The functions of source managers as follows,

Provide std API fro all TWAIN sources.

Provide selection of sources for user

Establish logical sessions between application and source.

Keep track of session.

Load or unload sources as demanded by application.

Pass all return code from source to application.

Maintain a default source.

Act as traffic cop to make sure that transaction andcommunication are routed to ap-

propriate sources.

Acquisition LayerThe acquisition layer contains virtual device and it acts directly with device driver. The

virtual layer is called source and the source can be local and logically connected to a local

device and performs the following functions.

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Device control Acquisition of data from device Transfer of data Provision of user interface to control the device

Cue chunkIt identifies a series of position in the waveform data stream.

Playlist chunk

It specifies a play order for a series of cue points

Associated chunk

Provides the ability to attach information such as labels.

Instrumental chunk

The wave form is perfect file format for sorting a sampled sound synthesizer’s sample

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