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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 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 RAM and ROM Hard drives CD-ROM, DVD, BlueRay USB memory modules Input devices 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 Audio Devices Amplifiers and Speakers Monitors Video Devices Projectors Printers Communication devices 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: 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