Multiplatform Applications 2009-10 Lecture 1: Introduction.

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 platformsComputers (you already know this bit)Mobile Devices such as phones and PDAs Interactive TelevisionOther 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 assignmentDesign 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

FacebookAdd me facebook.com/adam.isherwoodFan site: Multiplatform Applications

Free Microsoft Software

Level 3

In the final stretch leading to your degreeNot enough just to pass the module any more

You are expected to read the related materialCannot achieve a 1st 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 pagesMobile 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 designSingle page can contain multiple cards in one deckUser can step through cards as a form of navigationNext & 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 displayTypically 5 lines of text on screen14.4k 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

PlatformsThere 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 2009http://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 MediaThis 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 systemOvertaken 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 SystemUses 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/default.htm

Design considerationsTV 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 considerationsTVs 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 sizeA 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 AreaThe Action safe area of a screen is approximately 90%

of the screen so on PAL that is648 x 519 or rounded to 650 x 520

The Title safe area is smaller but again is approximated at 80% of the screen576 x 461 or rounded to 575 to 460Pixel size is different (1.06 width pixel onTV)

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

BuzzingEver 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