Introduction

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Nov 5, 2013 (3 years and 5 months ago)

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Multiplatform
Applications

2009
-
10 Lecture 1: Introduction

Today’s Session


Module Information


Mobile Platforms


Television Platforms

What is the module about?


Delivering applications and content on multiple
platforms


Computers (you already know this

bit)


Mobile Devices such as phones and
PDAs


Interactive Television


Other devices


Understanding the constraints different platforms
impose on the design process


One size does
not fit all!

Assessment


The module has a 50:50 split


Unseen examination

in January


Coursework assignment


Design and build a prototype of an application designed for
multiple platforms

Module Resources


Teaching

material on
moodle.bolton.ac.uk


Bookmarks: delicious.com/adamisherwood/mwd3002


Facebook


Add

me
facebook.com/adam.isherwood


Fan site: Multiplatform Applications


Free Microsoft

Software

Level 3


In

the final stretch leading to your degree


Not enough just to pass the module any more


You are expected to read the related material


Cannot achieve a 1
st

or a 2:1 just by repeating what is said
in the lectures


Your

answers and assignments must demonstrate
synthesis and
understanding

Prior Learning


Assume

you understand XML and XML Schema


Assume you can handle CSS and XHTML


Assume you can use Visual Studio .Net and a database

Practical

Skills


Publishing

using XML, CSS and XSLT


Mobile publishing using WAP and XHTML
-
MP


User Interface Considerations

Theory


Interactive Television


Enhanced Television


Smartphone
Application Development

Introduction to Mobile
Platforms

Publication Mechanisms


Write content using WAP/WML


Publish

web pages


Mobile version or standard


Write custom applications

In the beginning…


WAP: Wireless Application Protocol


WML: Wireless Markup Language


Early tool for delivering content to

mobile handsets


Supported by large number of phones


even relatively
simple or older handsets

Design Goals


Low bandwidth


9.6kbps


Low
colour
/monochrome


Runs

in little memory on slow processors


Rudimentary graphics support (WBMP format)

WML


XML based format using

defined set of tags


Scripting support


Intended for Tables, Links, Forms and simple graphics


Uses Deck of Cards metaphor for content design


Single page can contain multiple cards in one deck


User can step through cards as a form of navigation


Next & Previous buttons + named anchors to jump to
specific cards

WAP Gateway


Limitations


Designed late 1990s


Phones had very limited spec compared
to modern devices:


Monochrome or
greyscale

display


Typically 5 lines of text on screen


14.4k Modem for data access


No longer a mainstream platform

Modern Phones


3G

gives greater bandwidth


Larger screen resolution and greater
colour

depth


Embedded Web browsers


Closer to computer experience

Mobile
-
specific pages


Version of XHTML for the Mobile Platform XHTML
-
MP


Similar implementation of CSS
-
MP


Broadly similar capabilities to conventional web
browsers


Design considerations for mobile content to be covered
later

Custom

Applications


Networks like 3 offer apps such
as Skype and MSN


Apps like
Facebook

or Twitter
widely offered with high
-
end
phones/contracts


Multitude of
iPhone

apps to
access eBay, Amazon,
Facebook

etc.

Pushing

data not format


Apps send data to a
programme

running on the phone


Layout can use GUI elements from Java, Flash or Cocoa
as supplied by the phone OS


Delivers better interaction for customers by exploiting
phone functionality to the full


Further details in another lecture

Interactive TV

Platforms


There are several major platforms in use in the UK (the most
developed Digital TV country in the world)


Sky Digital


9.2
million subscribers


Virgin Media


3.6
million


Freeview



17.7 million


Freesat



0.6 million

Source: OFCOM April 2009

http://www.ofcom.org.uk/media/news/2009/04/nr_20090406a

Platform issues


Each platform has different operating systems and
technologies employed


Virgin media (formerly NTL/
Telewest
) use the Liberate
system which uses HTML


Freeview

uses MHEG 5 and open standard


Sky uses the
OpenTV

OS but their interactive services
can be built in
OpenTV

or in the new WML for Sky
language

Virgin Media


This system is the closest to web technology


Operates
on a two way interactive broadband link (usually
512K+)


Uses HTML and liberate specific extensions


Homepage for development hints is that supported by NTL at
www.digitalcabletv.co.uk


Includes a downloadable emulator

Freeview

system


Overtaken Sky


Will probably becomes the dominant platform over the course
of next 10 years


Uses MHEG 5 open standard technology


Multimedia and Hypermedia information coding Expert Group


See
http://en.wikipedia.org/wiki/MHEG
-
5

for a definition


Works
using
a carousel


play out of data with no return

Sky System


Uses Proprietary
OpenTV

technology and WML based
SkyWAP

browser (WTVML) for some content


Works using a carousel but can also use a 28.8k modem built
into the box (mostly for back channel work)


More details (and developers tools) at
http://www.skyinteractive.com/sky/our+services/ebusiness/d
efault.htm

Design considerations


TV screens are often physically large


32” (80cm) common


Broadcast TV is lower resolution than a computer monitor


Analogue TV heritage introduces problems


They
have some real issues as display devices

Display considerations


TVs
are

interlaced


That means they build the

frame one
line at a time with
alternate lines with each pass


Odd numbered lines used for first field, even for the second


Uses less transmission bandwidth for analogue broadcast


Older CRT televisions rely on afterglow and persistence of
vision to give flicker
-
free effect


Less appropriate for LCD TV and digital broadcast


Still an issue with HD


1080i
vs

1080p

Screen size


A PAL screen is .... (come on remember!)


But that does not mean you have that to use


A safe area is defined in the centre where you can display
content


This avoids the problems of over scanning or under scanning of
the picture


This overcomes the problems you will have with the wide
range of qualities and age of TV's

Safe and Title Area


The Action safe area of a screen is approximately 90% of the
screen so on PAL that is


648
x

519 or rounded to 650
x

520


The Title safe area is smaller but again is approximated at 80%
of the screen


576
x

461 or rounded to 575 to 460


Pixel size is different (1.06 width pixel
onTV
)


Good outline at
http://www.planetoftunes.com/dv/stills.html

Buzzing


Ever seen someone on
tv

in a tweed jacket


What happens?


Because of the low resolution of screen odd numbered
thickness lines cause bussing


Remember
don't use single lines in display


Also causes problems with text


All text and graphics must be anti aliased

Colours


Colours bleed into one another


Particularly primary colours


High contrast between colours causes problems (white and
black bleed together)


All designs must be tested through a
tv

first


Test colour combinations