Transcript 4_hardware - Personal web pages for people of Metropolia

Lecture 4: Multimedia Hardware
Introduction
 The word platform was traditionally
associated with hardware: the
computer platform.
 However, it can also describe
software as well as hardware (Mac
platform vs. Windows platform)
 WWW: the platform is the
combination of browser, computer
and OS (+ plug-ins)
Introduction
 For an offline application the OS and computer
is generally enough but sometimes more
detail, such as the graphics adapter, is
important
 Definition: The platform is whatever you have
to specify in order to run the application
 What kind of display is needed, or how big
hard disk, or how fast Internet connection
Introduction
 Three options that will be discussed in
relation to platforms:
 The delivery platform: what does your
user have to use in order to see your
application?
 The delivery medium: how do you get
the application to the user?
 The development and testing platform:
what do you need to use in order to
make the application in the first place?
Selection of the proper platform
 Selection of the proper platform for
developing your multimedia project may be
based on
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your personal preference of computer
your budget constraints
project delivery requirements
the type of material and content in the project
 Today you can produce multimedia projects
with equal ease in either the Windows or
Macintosh environment
Memory and storage devices
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RAM and ROM
Hard drives
CD-ROM, DVD, BlueRay
USB memory modules
Input devices
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Keyboards
Mice
Touchscreens
Magnetic Card Encoders and Readers
Graphics Tablets
Flat-bed Scanners
OCR Devices (Optical CharacterRecognition)
Infrared Remotes
Voice Recognition Systems
Digital Still and Video Cameras
Output hardware
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Audio Devices
Amplifiers and Speakers
Monitors
Video Devices
Projectors
Printers
Communication devices
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Cable Modems
xDSL technologies
Wireless (WLAN)
3G/4G
etc…
Delivery platforms
 Usually customers in Multimedia projects
have already knowledge of delivery
platforms, because they use a certain
machine and software, or because the
target market for the application has
mostly machines of a particular type.
 If a customer asks for your advice, you
have to
 Ask the right questions about the requirements
 Work out how to identify the positive and
negative factors influencing the choice
Online delivery
 WWW is somewhat simple for publishing since all web
browsers understand HTML; the web is the most
cross-platform format (despite some issues with
JavaScript and ActiveX etc).
 Issues affecting the delivery on Internet:
 Speed of access
 Updating
 Security/payment
 The “unlimited” size of the data space than can be
provided online
 You can restrict access, charge users for access, and
even keep track of who has accessed your information
and when
Online delivery
 The speed with which your potential users can access
your application is unpredictable; tens of Kbps – tens of
Mbps
 The bottleneck is the end-user’s web connection
 Do what you can: have a fast server and a fast Internet
connection
 Streaming and buffering are methods that try to remove
the problem of download times
 ONLINE DELIVERY PRO’S &CONS?
(groupwork)
Online delivery – pros and cons
 Pros
 A low cost and sophisticated possibilities
 The application can be fixed at any time
 Potentially an infinite amount of space to hold
information
 The web’s reach is global and instant
 Cons
 a heterogeneous user base
 you need to decide how much you can cater for
the differences in the users’ systems
 Security implications
 Slow connections
Mobile multimedia
 Mobile applications do not differ that
much from conventional computer
delivery
 The bandwidth problem is more
important, since it may be very
dependent on your distance from a
base station
 At least the billing is easy since the
system always tracks down the user
Interactive television
 The arrival of digital television brings with it
the possibility of interactive services
 Set-top boxes for televisions; also
integrated models are available; IPTV
 Video-on-demand (VOD) may provide
another market for interactive services on
the TV or via net to a PC (push and pull
models)
 Today’s set-top boxes use push model
Computers and O/S’s
 For multimedia, there are several
issues:
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Screen resolution, bit depth
Sound parameters
The speed of the CD/DVD/BlueRayDVD
The way that the video is handled
The amount of RAM in the system
The size of the hard disk
Computers and O/S’s
 PC is not only a Windows machine, it
can also be a Macintosh or a Linux
system
 Multimedia products usually support
only Windows and Apple
 Competing platforms: game consoles,
such as Xbox, PS3, GameCube and
their forthcoming successors
Criteria for offline choice
 As a developer you don’t have the freedom
to choose the platform best suited to
deliver your multimedia vision
 The market will drive your choice (which
machine is prevalent in the target sector)
 Businesses used to have business machines
(PC’s with no multimedia capabilities) but it
has changed
 Do a research and try to find the lowest
common denominator for the machinery
your customers have
Cross-platform chameleons
 It is possible for a computer to emulate
another
 The more powerful the platform, the more
easily it can emulate another
 A further refinement of this technique is the
virtual machine, where the application code
runs in a specified environment
 The environment is provided by a program
(the virtual machine) that runs on the host
machine
 To run the application on a new platform,
you need only a new virtual machine
Virtual machines
 Virtual machines need fast
processors, otherwise it’s best suited
to low-interactivity applications,
because the interpreted software is
likely to run more slowly than
software compiled to run directly on
the target machine
 There is also the problem of the
abilities and drawbacks of particular
machines. A virtual machine has to
have an audiovisual capability, and
this will be the same or less than the
capabilities of its host
Incompatibility situations
 The software does not work at all
 The software runs in a less optimum
way; performance drops, maybe
fewer colors in pictures, movies may
run sluggishly
 Incompatibility issues still exist on
the web
Delivery medium
 Besides deciding on what computer
platform the end-user will actually
use your production, there is the
question of how you will actually
distribute the content.
 If it’s a web page, then the WWW is
the medium
 To a certain extent this will depend
on the size of the application, and
might even have been specified up
front
Optical disks
 This medium has become universal; it may
never lose its supremacy as a carrier
 Different incarnations: CD-ROM, DVD,
BlueRay
 DVD is a higher-density format that CD
(the basics of the technologies are quite
similar)
 Replication of optical disks is cheap
Hybrid delivery
 Sometimes you can use both on- and
offline delivery (quite common today)
 Web links can be part of DVDs
 CDs and DVDs are often updated
from the web (fixes and additions are
saved on the hd)
Websites and server/browser
balance
 There are four software components in the web
page chain: the page itself, the browser, any
software that dynamically generates the pages
(PHP or similar CGI system), and the server
itself
 The web page runs on the browser, and the
dynamic page generation software runs on the
server
 HTML, Java, JavaScript and plug-ins are part of
the page/browser combination
 Sometimes you have to decide whether a
particular task is best handled by HTML or a
server program
Websites and server/browser
balance
 Particular task can be carried out at
the client side or the server side
 JavaScript is run on the client side
and CGI programs run on the server
 Both technologies have their
advantages
Platforms for development
and testing
 You do not have to develop your application
on the delivery platform
 A cross-platform application is usually
developed on one and tested on all delivery
platforms (even a low-level code can be
produced on a different computer using a
cross-compiler)
 Even though majority of multimedia
applications are created for Windows, they
are quite often developed on Macintosh
(not that much anymore, but few years ago
the software was usually first released for
Mac)
Platforms for development and
testing
 Create and manipulate your assets (sound,
graphics etc) in the highest convenient
standard and convert down, if necessary, at
the last moment
 You must have at least one workstation that is
similar to the delivery platform so that you can
test the performance and carry out debugging
 Remember that you can never have
all possible platform combinations
Author once and deliver
everywhere
 We need techniques that allow us to author
once an deliver on many platforms
 XML is one part of the solution to this: it
allows the content structure to be
separated from the way it is laid out; layout
can change depending on the platform
 Although we are talking about media
convergence, the range of platforms
available is still increasing