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
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
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
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