1 © Netskills Quality Internet Training, University of Newcastle Multimedia Web Pages © Netskills, Quality Internet Training, University of Newcastle Netskills is a trademark of Netskills, University of Newcastle. Partly funded by the

2 © Netskills Quality Internet Training, University of Newcastle Topics What is multimedia? Multimedia formats and technologies Audio Video Streaming media SMIL VRML

3 © Netskills Quality Internet Training, University of Newcastle Multimedia Web Pages What is multimedia? Any combination of: Text Graphics Animation Audio Video Virtual Reality Example:

4 © Netskills Quality Internet Training, University of Newcastle Viewing Multimedia: Plug-ins Browsers limited to displaying text and images Plug-ins enable browsers to handle other media Video, animation… Plug-ins are usually freely distributed Software to generate files viewed by plug-in are usually commercial Newer browsers have pre-installed plug-ins Plug-in resources available at:

5 © Netskills Quality Internet Training, University of Newcastle Examples of Plug-ins Flash, Real Player and QuickTime Support animation, audio, video, interaction and virtual reality Can provide user controls: Zoom, fast forward, rewind… Examples:

6 © Netskills Quality Internet Training, University of Newcastle Multimedia in Web Pages Media files included in a web page using: tag in Internet Explorer tag in Netscape browsers Can use both tags to increase compatibility <object classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B" codebase=" <embed src="tune.wav" pluginspage=" Range of attributes can also be used Autoplay, height, width, loop… Repeat for both and

7 © Netskills Quality Internet Training, University of Newcastle Audio Formats There are many audio formats, including:.wav Microsoft's sound format.aiff Originally for Mac, now also for PCs.au Audio format developed by Sun.ra RealAudio, increasingly popular commercial format.midi Musical Instrument Digital Interface

8 © Netskills Quality Internet Training, University of Newcastle MP3 Format Format for efficient compression of digital audio 'Near CD' quality audio with small file sizes Non-proprietary format (open standard) Files can be distributed via the internet Using MP3 Create MP3s from CDs using encoding software Download (not always legal!) Playback requires MP3 player - e.g. Winamp Causing radical changes in the music industry Record companies selling MP3 albums via the web

9 © Netskills Quality Internet Training, University of Newcastle Video Formats Usually include both audio and video Can be very large files Slow to download Common formats include:.avi - Audio Video Interleave Developed by Microsoft.mov - QuickTime movie format Developed by Apple, but now cross-platform Also supports QuickTime 3D or VR.mpg - Moving Pictures Experts Group ISO standard for audio and video compression

10 © Netskills Quality Internet Training, University of Newcastle Streaming Media Streaming media can be played whilst downloading Less time waiting for playback to begin Streamable media Audio, video, slides… Different media can be streamed simultaneously Can be pre-recorded or live Quality of playback is bandwidth dependent Buffering used to smooth network delays Examples of streaming media: video.ldc.lu.se/terena.htm news.bbc.co.uk/1/hi/programmes/newsnight/default.stm

11 © Netskills Quality Internet Training, University of Newcastle Products for Streaming RealNetworks RealProducer Creation of files in 'rm' format RealServer Streamed delivery of files RealPlayer Playback of rm files (free) Apple QuickTime QuickTime player Macromedia Director (Shockwave) Shockwave files are streamed Integrates with RealAudio/RealVideo uk.real.com

12 © Netskills Quality Internet Training, University of Newcastle SMIL Synchronised Multimedia Integration Language HTML-like language for choreographing multimedia Audio, video, images, animation, text… SMIL file instructs client to: Retrieve media files from server(s) Synchronise playback Requires plug-in/player QuickTime (SMIL 1.0) Real Player (SMIL 2.0) IE5.5 (+) supports a Microsoft implementation of SMIL W3C recommendation

13 © Netskills Quality Internet Training, University of Newcastle VRML Virtual Reality Modelling Language Three-dimensional (3D) imaging format Object properties specified using text-based language Cube {depth 1 height 1 width 1} VRML player controls allow users to manipulate view of object Pan, zoom, rotate, fly, etc. Examples of VRML:

14 © Netskills Quality Internet Training, University of Newcastle Legal requirement for materials to be accessible Regardless of users ability/disability Disability Discrimination Act (1995) Special Educational Needs and Disability Act (2002) Multimedia accessibility issues Large file size can slow content delivery Playback typically requires plug-ins Media may be inaccessible to: Users with disabilities (deaf, blind…) Assistive technologies (e.g. screenreaders) Only use multimedia where justified Provide appropriate alternatives Text transcripts, captioned video, audio descriptions... Accessibility

15 © Netskills Quality Internet Training, University of Newcastle Summary Web pages can include a range of media Audio, video, animation, VRML… Formats for each media may have different characteristics Quality, compression, file size, streaming… Select appropriate format for each media Media playback typically requires plug-ins Will these be available to your users? Streaming improves delivery of large media files over the web