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LECTURE 4Technological Aspects

Of Multimedia

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Basic ConceptsMPC StandardsHardware Storage DevicesCD-ROMOther Types of CD-ROMDigital Versatile Disk (DVD)CD-IProprietary SystemsMass Storage DevicesHDTVDigital Audio BroadcastingMicrophones Music related Technologies

Contents

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Analog Binary SystemBits & BytesAnalog to Digital Converter (ADC) ADC are electronic devices which converts analog signals to a digital form for use in computers, digital audio and other communication equipment.

Digital to Analog Converter (DAC) Convert digital signals into analog.

Basic Concepts

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MPC

MPC (Multimedia PC) was an early attempt to specify a standard for multimedia computing by computer manufacturers.

MPC Specification 386 SX, 16 MHz Hard disk : 30 Mb RAM : 2 MB CD-ROM Sound Card (8-bit) ,Microphone Input, Audio Output

MPC Standards

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MPC 2The MPC 2 Specification :486SX, 25 MHzHard Disk : 160 MBRAM : 4 MBCD-ROMSound Card (16 bit), MIDI Playback

MPC 3

The MPC 3 Specification:Pentium, 75 MHzHard Disk : 540 MBRAM : 8 MBCD-ROM Quad SpeedMPEQ & Sound Card

MPC 2 and MPC 3

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Fixed Hard DisksFloppy DisksHigh Capacity DisksPCMCIA CardsOptical DisksRewritable Optical DisksDigital Audio Tape (DAT)Digital Linear Tape (DLT)Magnetic TapeStorage Consideration for Product Delivery

Hardware Storage Devices

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PCMCIA Cards

The Personal Computer Memory Card InternationalAssociation (PCMCIA) established a standard forcredit card sized devices which were capable of being used interchangeably between computers.

The PCMCIA standard defines the physical aspects,electrical specifications and software architecturefor cards. All are 2.12 inches wide by 3.37 inches deep but the thickness varies. The standard defines 3types of card: Type 1 - used for memory enhancements e.g. RAM Type 2 - used for memory enhancements and I/O devices e.g. modems and network cards Type 3 - used for I/O devices and storage devices

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There are 2 factors need to be considered when examining the performance of hardware storagedevices; the access time and the data transfer rate.

Hardware storage devices can be categorised into sequential access media and direct access (also known as random access) media.

Data held on a direct access media is stored in a location that is determined using an address generating algorithm operating on the data record’s key.

Hardware Storage

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Storage Considerations for Product Delivery

The choice of delivery media to be used for anymultimedia system depends on a number of factors.

SpeedMedia such as video and large graphic images placehigh demands on the data transfer rate of the mediaused.

CostHere not only should the cost of the data of the mediabe taken into account but also cost of recording data onto the chosen media

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Storage Considerations for Product Delivery

Storage CapacityMultimedia projects tend to require a large amountof storage capacity due to the use of video, soundand graphics.

Installed BaseThe choice of delivery media should also take intoaccount its popularity.

RewritabilitySome applications require periodical updating. Not alltypes of media can be rewritten to so again this mustbe taken into account

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What is CD-ROM?History of CD-ROMAdvantages & Disadvantages of CD-ROMCD-ROM Production CostsCD-ROM Storage Capacity CD-ROM StandardsRed, Yellow, Green, Orange, Blue, White Book StandardsISO-9660 Standard

CD-ROM

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CD-ROM looks exactly the same as the audio compactdisks, both are digital but on CD-ROMs the bits containsdata rather than music.

CD-ROMs are widely used for music, games, computerprograms, distributing and backing up data.

What is CD-ROM ?

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1977 - The first digital audio disc prototype were shown in Japan.

1980 - Sony and Philips propose a CD standard.

1982 - Sony & Philips develop CD products.

1983 - CD technology is introduced in the USA

1984 - Second generation CD players are released.

1988 - CD-recordable (CD-R) technology is introduced.

1996 - DVD technology is introduced.

History of CD-ROM

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Advantages of CD-ROM

Holds large amount of data.Cannot be tampered or accidentally erased.CD-ROMs are not damaged by magnetic fields or x-rays. Have faster access read times than magnetic tape.Cheap to produce.

Disadvantages of CD-ROM

Generally slower than hard disks.Content is static.Can easily pirated.

Advantages & Disadvantages of CD-ROMAdvantages & Disadvantages of CD-ROM

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There are many different ways of encoding data on a CD-ROM disk.

In order to decode and retrieve the information stored inthe disk, it is necessary for the computer which reads the disk understand how it is arranged and what various codes mean.

The organisation of data and sector structure of a CD-ROMdisk is defined by the Yellow Book produced by Philip andSony, however it does not define the specific structure ofthe files, directories and paths in which those data are stored.

The ISO 9660 defines the external characteristics of the blocks in which data are stored on the disk. Almost all systems support ISO 9660.

CD-ROM Standards

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Compact Disk Digital Audio (CD-DA)

CD-ROM Extended Architecture (CD-ROM XA) The CD-ROM/XA differs from the basic CD-ROM in that the data is recorded in a more efficient way, employing better compression techniques.

Video CD The market is expected to grow alongside DVD. VCD is based on MPEG1 digital video. The ActiveMovie software allow VCD’s to be played on the PC with full screen video.

Other Types of CD-ROM

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Introduction

DVD is set to make an enormous impact on both the home and office environments. The DVD specification was announced in 1995 and is little larger than the standard CD but has a much larger (4.7 GB of data) capacity. The advent of double sided DVD will increase this capacity to 8.5GB or 4 hours of video.

Digital Versatile Disk (DVD)

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DVD-Audio capable of storing far more audio data than a CD & up to 5 channels can be used for Dolby surround use.DVD- ROM Enable far more sophisticated and complex multimedia systems to be developed.DVD-Video DVD is seen to be future distribution medium for movies.DVD-R A worm (write once read many) version of the DVD capable of supporting any of the above formats.DVD-E Similar to DVD-R but can be written to and erased many times.

Formats of DVD

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CD-I

Music with pictures requires a high quality stereosound channel plus an equivalent availablebandwidth for slowly changing still pictures.

Philips and Sony create an all-embracing single standard for this form of electronic publishing.This system is called Compact Disc Interactive.CD-I is both a media standard and complete specification..

Among the applications of CD-I are: Audio recording Games Entertainment and Educational materials

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What are proprietary Systems? Proprietary systems are developed to capture a specific market sector by introducing machines with new features.

Examples Commodore Dynamic Total Vision (CDTV) Video Information Systems (Tandy VIS) 3DO Nintendo 64 Sega Satum Sony Playstation

Proprietary Systems

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Mass Storage Devices

As the amount of data being stored on a computersis increasing dramatically there is a growing requirement for incorporating multiple storage unitsinto one system.

There are 3 key types of mass storage technology:

Optical jukeboxes which utilise many optical disks.

Tape libraries

RAID (Redundant Array of Inexpensive Disks) systems

which incorporate a number of disks into a system

providing increased access times and some form of

data protection.

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Introduction High Definition television (HDTV) has been much heard but has got off to a very slow start with little consumer interest.

Reasons for HDTV delays Existing Infrastructure Lacked of agreed worldwide standards High Costs Bandwidth

HDTV

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VIDEOGAMES

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VIDEOGAME

Nintendo Game Cube

Sony PlayStation2

Microsoft XBox

Games #

CPU

RAM

Hard Drive

Internet

DVD Drive

5-7

485MHz

40MB

No

No

No

175

295MHz

32MB

40GB (ext.)

External

Yes

15-20

733MHz P3

64MB

8GB

Built-in

Yes

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Introduction Using latest technology to introduce full digital broadcasting.

Benefits Improved CD quality sound. No interference. More accurate tuning. Ability to time-shift programmes as required.

Digital Audio Broadcasting (DAB)

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TypesMicrophones can be categorised in two ways, either bythe type of transducer used, or by the acoustic propertiesof the microphone.

Transducer types Dynamic Condenser Ceramic Carbon

Microphones

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Music Related Technologies

Mixers

The mixer is one of the most essential items ofany recording studio. It is a piece of hardwarewhich enables the user to take numerous signals,apply sound processing, control relative volumes,and route them to one of many outputs.

SamplersA sampler records sound digitally. After a particularsound has been recorded into the machine’s RAM, it can then be played and controlled by a MIDI keyboard.

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Music Related Technologies

Synthesisers

Sequencer

Synthesisers are instruments which create tones,played by a keyboard. Today’s synthesisers are MIDI instruments, either with a keyboard on which to play the notes, or in a modular form towhich a MIDI controller can be attached.

The sequencer is a device which records MIDI data for editing and playback. The sequencer existin 2 guises: either in hardware form, or as softwarefor a computer.

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Music Related Technologies

Musical Instrument Digital Interface (MIDI)

The MIDI was introduced in early 80s and it isthe international standard for digital music.

Its importance is that it specifies the cabling and aserial communications protocol which allows different electronic instruments, equipment and computers to work together. Benefits of MIDI :

It provides a standard method of controlling MIDIcompatible musical instruments.It allows many MIDI compatible instruments to becontrolled centrally.MIDI files are very small.