LECTURE 4 Technological Aspects Of Multimedia

1

Contents

Basic Concepts MPC Standards Hardware Storage Devices CD-ROM Other Types of CD-ROM Digital Versatile Disk (DVD) CD-I Proprietary Systems Mass Storage Devices HDTV Digital Audio Broadcasting Microphones Music related Technologies

2

Basic Concepts

Analog Binary System Bits & Bytes Analog 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.

3

MPC Standards

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 4

MPC 2 and MPC 3

MPC 2

The MPC 2 Specification : 486SX, 25 MHz Hard Disk : 160 MB RAM : 4 MB CD-ROM Sound Card (16 bit), MIDI Playback

MPC 3

The MPC 3 Specification: Pentium, 75 MHz Hard Disk : 540 MB RAM : 8 MB CD-ROM Quad Speed MPEQ & Sound Card 5

Hardware Storage Devices

Fixed Hard Disks Floppy Disks High Capacity Disks PCMCIA Cards Optical Disks Rewritable Optical Disks Digital Audio Tape (DAT) Digital Linear Tape (DLT) Magnetic Tape Storage Consideration for Product Delivery 6

PCMCIA Cards

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

The PCMCIA standard defines the physical aspects, electrical specifications and software architecture for cards. All are 2.12 inches wide by 3.37 inches deep but the thickness varies. The standard defines 3 types 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 7 Type 3 - used for I/O devices and storage devices

Hardware Storage

There are 2 factors need to be considered when examining the performance of hardware storage devices; 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.

8

Storage Considerations for Product Delivery

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

Speed

Media such as video and large graphic images place high demands on the data transfer rate of the media used.

Cost

Here not only should the cost of the data of the media be taken into account but also cost of recording data onto the chosen media 9

Storage Considerations for Product Delivery Storage Capacity

Multimedia projects tend to require a large amount of storage capacity due to the use of video, sound and graphics.

Installed Base

The choice of delivery media should also take into account its popularity.

Rewritability

Some applications require periodical updating. Not all types of media can be rewritten to so again this must 10 be taken into account

CD-ROM

What is CD-ROM?

History of CD-ROM Advantages & Disadvantages of CD-ROM CD-ROM Production Costs CD-ROM Storage Capacity CD-ROM Standards Red, Yellow, Green, Orange, Blue, White Book Standards ISO-9660 Standard 11

What is CD-ROM ?

CD-ROM looks exactly the same as the audio compact disks, both are digital but on CD-ROMs the bits contains data rather than music.

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

12

History of CD-ROM

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.

13

1996

- DVD technology is introduced.

Advantages & Disadvantages of CD-ROM 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.

14

CD-ROM Standards

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

In order to decode and retrieve the information stored in the 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-ROM disk is defined by the Yellow Book produced by Philip and Sony, however it does not define the specific structure of the 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 15 systems support ISO 9660.

Other Types of CD-ROM

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. 16

Digital Versatile Disk (DVD)

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.

17

Formats of DVD

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 18 times.

CD-I

Music with pictures requires a high quality stereo sound channel plus an equivalent available bandwidth 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 19

Proprietary Systems

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 20

Mass Storage Devices

As the amount of data being stored on a computers is increasing dramatically there is a growing requirement for incorporating multiple storage units into 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 21 data protection.

HDTV

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 22

VIDEOGAMES

23

VIDEOGAME

Games # Nintendo Game Cube

5-7

Sony PlayStation2

175

Microsoft XBox

15-20

CPU

485MHz 295MHz 733MHz P3

RAM

40MB 32MB 64MB

Hard Drive

No 40GB (ext.) 8GB

Internet

No External Built-in

DVD Drive

No Yes Yes 24

Digital Audio Broadcasting (DAB)

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 .

25

Microphones

Types

Microphones can be categorised in two ways, either by the type of transducer used, or by the acoustic properties of the microphone.

Transducer types

Dynamic Condenser Ceramic Carbon 26

Music Related Technologies

Mixers

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

Samplers

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

27

Music Related Technologies

Synthesisers

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 to which a MIDI controller can be attached.

Sequencer

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

28

Music Related Technologies

Musical Instrument Digital Interface (MIDI)

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

Its importance is that it specifies the cabling and a serial communications protocol which allows different electronic instruments, equipment and computers to work together. Benefits of MIDI : It provides a standard method of controlling MIDI compatible musical instruments.

It allows many MIDI compatible instruments to be controlled centrally.

29 MIDI files are very small.