School of Computer Science & Information Technology

School of Computer Science & Information Technology

G6DPMM - Lecture 8G6DPMM - Lecture 8

Multimedia Hardware & Storage TechnologyMultimedia Hardware & Storage Technology

Multimedia Development PlatformsMultimedia Development Platforms Microsoft WindowsMicrosoft Windows

Multimedia capable since 3.1 (c. 1992)Multimedia capable since 3.1 (c. 1992) Win32 – Windows API since 1995Win32 – Windows API since 1995 DirectX – Game API since 1995DirectX – Game API since 1995

DirectDraw (bitmap graphics), Direct3D (3D graphics), DirectInput (mouse DirectDraw (bitmap graphics), Direct3D (3D graphics), DirectInput (mouse and other controllers), DirectPlay (network communications), DirectSound and other controllers), DirectPlay (network communications), DirectSound (waveform sound), DirectMusic (high level music), DirectShow (streaming (waveform sound), DirectMusic (high level music), DirectShow (streaming audio/video), DirectSetup (installation)audio/video), DirectSetup (installation)

Frequent version updates (9.0) and compatibility issuesFrequent version updates (9.0) and compatibility issues

WinFX – new API in LonghornWinFX – new API in Longhorn

Apple MacintoshApple Macintosh Always multimedia capable (i.e. since 1984)Always multimedia capable (i.e. since 1984) OS has changed radically several times – Unix since the release OS has changed radically several times – Unix since the release

of OSX in 2001of OSX in 2001 Quicktime – multimedia framework released in 1991Quicktime – multimedia framework released in 1991

Multimedia Development Platforms (cont.)Multimedia Development Platforms (cont.)

Windows vs Mac for multimedia developmentWindows vs Mac for multimedia development Historically multimedia developers have mostly used Historically multimedia developers have mostly used

MacintoshMacintosh Now hardware is comparableNow hardware is comparable Most tools are available on bothMost tools are available on both Mac slightly more expensive, but have far more bundled Mac slightly more expensive, but have far more bundled

multimedia development hardware and softwaremultimedia development hardware and software Other platformsOther platforms

LinuxLinux Viable delivery platform, not used widely for development Viable delivery platform, not used widely for development

(due to lack of tools)(due to lack of tools) Other UnixOther Unix

Silicon graphicsSilicon graphics Very high end workstationsVery high end workstations Now largely overtaken by Macs and WindowsNow largely overtaken by Macs and Windows

Requirements for MultimediaRequirements for Multimedia Fast processorFast processor High quality displayHigh quality display High quality soundHigh quality sound All modern computers have these!All modern computers have these!

Suitable i/o devicesSuitable i/o devices NB mouse not always suitable – eg for public kiosksNB mouse not always suitable – eg for public kiosks

High capacity storageHigh capacity storage

Magnetic Storage DevicesMagnetic Storage DevicesSliders physically move an Sliders physically move an

electromagnetic head over the surface electromagnetic head over the surface of a spinning disk.of a spinning disk.

Ferrous coating is magnetized, Ferrous coating is magnetized, storing bits.storing bits.

Bits are arranged in concentric Bits are arranged in concentric circles – called tracks.circles – called tracks.

Magnetic Storage Devices (2)Magnetic Storage Devices (2) Floppy diskFloppy disk

1.4 Mb & very slow (0.06 Mb per second)1.4 Mb & very slow (0.06 Mb per second) Rapidly becoming obsolete – useless for multimediaRapidly becoming obsolete – useless for multimedia

Hard diskHard disk Fast, cheap and largeFast, cheap and large Typically 60Gb – 1TbTypically 60Gb – 1Tb 16-66 Mb per second16-66 Mb per second Can now be made very smallCan now be made very small

Zip / Jaz disks (Iomega)Zip / Jaz disks (Iomega) 100Mb – 2 Gb100Mb – 2 Gb Up to 20 Mb per secondUp to 20 Mb per second Used as “giant floppy”Used as “giant floppy” Other similar devicesOther similar devices

Flash StorageFlash Storage Flash RAM is non-volatile RAMFlash RAM is non-volatile RAM

Retains data even when there is no currentRetains data even when there is no current May be formatted and used as if it were magnetic mediaMay be formatted and used as if it were magnetic media

Flash RAM cartridgesFlash RAM cartridges Various proprietary standardsVarious proprietary standards

Memory Stick (Sony)Memory Stick (Sony) SmartMediaSmartMedia CompactFlashCompactFlash SecureDigital (SD) MemorySecureDigital (SD) Memory

Typically 8-512MbTypically 8-512Mb Used in devices such as digital cameras & MP3 playersUsed in devices such as digital cameras & MP3 players

Portable USB devicesPortable USB devices Flash RAMFlash RAM Hard diskHard disk

Optical Storage DevicesOptical Storage Devices

Laserdisk (analogue – largely obsolete)Laserdisk (analogue – largely obsolete) CD-ROM & DVD (digital)CD-ROM & DVD (digital) Pits are moulded into a polycarbonate surface, Pits are moulded into a polycarbonate surface,

encoding digital dataencoding digital data This surface is coated with a This surface is coated with a

reflective aluminium layerreflective aluminium layer Data is read by deflecting Data is read by deflecting

lasers while the disk is lasers while the disk is spinningspinning

Compact DiskCompact Disk CD-DA (Digital Audio)CD-DA (Digital Audio)

Developed for the music industry in 1982 by Sony & Philips Developed for the music industry in 1982 by Sony & Philips Stores 70 minutes stereo digital audioStores 70 minutes stereo digital audio

EncodingEncoding Transition between pit and land represents 1Transition between pit and land represents 1 No transition represents 0No transition represents 0

ManufactureManufacture Pre-masteringPre-mastering Glass masterGlass master PressingPressing

Mastering is expensiveMastering is expensive Pressing is extremely cheapPressing is extremely cheap

CD-ROMCD-ROM CD-ROM (Read Only Memory)CD-ROM (Read Only Memory)

Developed in 1985 by Sony & PhilipsDeveloped in 1985 by Sony & Philips Provides digital data storage for computersProvides digital data storage for computers 650-700Mb650-700Mb Modern CD-ROM is capable of an average data transfer rate of Modern CD-ROM is capable of an average data transfer rate of

4.5 Mb/s4.5 Mb/s

Two important international standardsTwo important international standards European Computer Manufacturers AssociationEuropean Computer Manufacturers Association

ECMA-119 – defines CD-ROM physical hardwareECMA-119 – defines CD-ROM physical hardware International Standards OrganisationInternational Standards Organisation

ISO-9669 – defines CD-ROM file and directory conventionsISO-9669 – defines CD-ROM file and directory conventions Many other standards (and compatibility issues) in the past. Many other standards (and compatibility issues) in the past.

These are now largely resolved, and CD-ROM is mostly These are now largely resolved, and CD-ROM is mostly interoperableinteroperable

CD-R & CD-RWCD-R & CD-RW

CD-R – CD WriteableCD-R – CD Writeable Write once, thereafter use as a CD-ROMWrite once, thereafter use as a CD-ROM Drive has a more powerful laser that can burn a dye layer of an otherwise Drive has a more powerful laser that can burn a dye layer of an otherwise

reflective blank – therefore creating optical “pits”reflective blank – therefore creating optical “pits” CD-RW – CD RewritableCD-RW – CD Rewritable

Can be overwritten many timesCan be overwritten many times Pits can be ereased by the laser melting the plastic Pits can be ereased by the laser melting the plastic

CD-R & CD-RW are most useful for backup and pre-masteringCD-R & CD-RW are most useful for backup and pre-mastering Cannot be mass produced Cannot be mass produced

Blanks are more expensive, and burning takes too longBlanks are more expensive, and burning takes too long Supposedly less robust than CD-ROMSupposedly less robust than CD-ROM CD-writers require lasers that can operate at different power levelsCD-writers require lasers that can operate at different power levels Most CD-writers are compatible with CD-ROM, CD-R & CD-RWMost CD-writers are compatible with CD-ROM, CD-R & CD-RW

DVDDVD Digital Video Disk / Digital Versatile DiskDigital Video Disk / Digital Versatile Disk Developed by Sony & Phillips in 1994Developed by Sony & Phillips in 1994

Replacement for VHS and LaserdiskReplacement for VHS and Laserdisk

Same technology as CD-ROM with the following differencesSame technology as CD-ROM with the following differences Track width – half (0.74Track width – half (0.74µ µ vs 1.6 vs 1.6 µ)µ) Pit length – half (0.4Pit length – half (0.4µ µ vs 0.83 vs 0.83 µ)µ) Speed – thrice (3.8m/s vs 1.3 m/s)Speed – thrice (3.8m/s vs 1.3 m/s) Laser wavelength red rather than infra-red (365nm vs 780 nm)Laser wavelength red rather than infra-red (365nm vs 780 nm) Disk may be 2-sidedDisk may be 2-sided Better error correction (by an order of magnitude)Better error correction (by an order of magnitude)

Hence much higher data capacityHence much higher data capacity 4.7 – 17.08 Gb, depending upon format4.7 – 17.08 Gb, depending upon format

DVD (cont.)DVD (cont.)

DVD backwardly compatible with CDDVD backwardly compatible with CD Manufacture very similar to CDManufacture very similar to CD Designed for video, audio & multimediaDesigned for video, audio & multimedia Specification includes:Specification includes:

File systemFile system Video compression standardsVideo compression standards Audio compression standardsAudio compression standards Copy protectionCopy protection Region lockingRegion locking

DVD WritingDVD Writing Technology similar to CD-writersTechnology similar to CD-writers However, there are several competing standardsHowever, there are several competing standards

DVD-R / DVD-RWDVD-R / DVD-RW DVD+R / DVD+RWDVD+R / DVD+RW DVD-RAMDVD-RAM

These standards have different physical mediaThese standards have different physical media Drives and software may be standard specific or Drives and software may be standard specific or

multi-standardmulti-standard DVD in the futureDVD in the future

Technology for HDTVTechnology for HDTV Currently warring standards!Currently warring standards!

Standards

Standards are crucial for interoperability of Standards are crucial for interoperability of hardware and softwarehardware and software Hardware standardsHardware standards Data standardsData standards Software standardsSoftware standards

Formalised StandardsFormalised Standards de factode facto standards (industry standards) standards (industry standards)

Formalised Standards

Formal standards are published by recognised standards Formal standards are published by recognised standards bodiesbodies

Governmental standards bodiesGovernmental standards bodies American National Standards Institute (ANSI)American National Standards Institute (ANSI) British Standards Institute (BSI)British Standards Institute (BSI)

International Organisation for Standardisation (ISO)International Organisation for Standardisation (ISO) Professional BodiesProfessional Bodies

Institute for Electrical and Electronic Engineers (IEEE)Institute for Electrical and Electronic Engineers (IEEE) International Telecommunications Union (ITU)International Telecommunications Union (ITU) Electronic Industries Association (EIA)Electronic Industries Association (EIA)

Industry Standards

Created by corporations (eg IBM, Microsoft, Created by corporations (eg IBM, Microsoft, Intel, Apple etc)Intel, Apple etc)

Open Open vsvs closed standards closed standards Industry Standards may or may not become Industry Standards may or may not become de de

facto facto standards in common usestandards in common use Open industry standards, if they are widely Open industry standards, if they are widely

adopted (ie adopted (ie de factode facto standards) are standards) are sometimessometimes adopted by standards organisationsadopted by standards organisations

De facto standardsDe facto standards Anyone can create a standard! It only matters if it is widely used.Anyone can create a standard! It only matters if it is widely used.

Control of successful standards is an issueControl of successful standards is an issue They may become formal standardsThey may become formal standards They may establish their own organisationThey may establish their own organisation

WWWWWW Invented by Tim Berners-Lee at CERN in 1990Invented by Tim Berners-Lee at CERN in 1990 W3C founded by MIT in 1994W3C founded by MIT in 1994 Now W3C is essentially an independent standards bodyNow W3C is essentially an independent standards body

Hardware StandardsHardware Standards

Many hardware standards are formalised and tightly Many hardware standards are formalised and tightly defined egdefined eg RS-232 (serial) - EIARS-232 (serial) - EIA IDE - originally Compaq, now ANSIIDE - originally Compaq, now ANSI SCSI - originally Seagate, now ISOSCSI - originally Seagate, now ISO

Some standards are more problematicSome standards are more problematic

The VGA “standard”The VGA “standard”

Video Graphics ArrayVideo Graphics Array Industry standard - set by IBM in mid 1980’sIndustry standard - set by IBM in mid 1980’s VGA displays VGA displays eithereither 320 x 200 in 256 colours 320 x 200 in 256 colours oror 640 x 480 in 640 x 480 in

16 colours16 colours

Super-VGA (SVGA)Super-VGA (SVGA) This is not a standard - video hardware has proprietary low This is not a standard - video hardware has proprietary low

level APIlevel API This causes This causes majormajor compatibility problems for multimedia compatibility problems for multimedia

Partly solved by MS WindowsPartly solved by MS Windows More completely solved by DirectXMore completely solved by DirectX