ppt

Audio and Video

Curtis Thomas

385E Information Architecture and Design I

Overview

• The Medium

• Popular Formats

• Design Guidelines

• Library of Congress Analysis

• IA and Audio / Video

The Medium

• Streaming Media

• Codecs

Streaming Media

Streaming media was made possible by the creation of two protocols:

• User Datagram Protocol (UDP)• RealTime Streaming Protocol (RTSP)

UDP and RTSP

• Continuously send information even when data dropout occurs

• Users get information in chunks

• Network congestion can cause a lapse in the video or audio feed

Codecs• Transform data streams by discarding any

unnecessary data

• Audio codecs discard frequencies that fall outside of the range of human hearing

• Video codecs predict picture content from previously viewed images in the stream

Popular Formats

• RealMedia

• Apple’s QuickTime

• MPEG, MP3, WAV

RealMedia RealMedia is a streaming audio and video

format

• Useful for slower Internet connections• Reduced audio quality• Slower video playback (3 to 6 fps)• Heavily affected by Internet traffic

QuickTime Offers a streaming format as well as

smaller downloadable files

• Higher quality streaming format than RealMedia

• Average file size is 5 to 6 megs per minute of video

• Greater bandwidth demands

Various FormatsMPEG (Video)• High quality• 9 megs per minute of video

MP3 (Audio)• High quality, fast downloads

WAV (Audio)• Highest audio quality• Longer download times• Must wait for download to finish completely

General Design Guidelines

• Inform users of technological demands• Provide clear access to software• Avoid gratuitous “eye candy”• Stick with standard formats• Provide controls

Video Guidelines

• Plain page summary

• Screenshots from video content

• Segment long clips

• Choose clips with minimal motion

Audio Guidelines

• Summarize content

• Give users control

• Provide estimated download times

Library of CongressAmerican Memory Website

Video Content

Audio Content

IA and Audio / VideoThe key to successful Web multimedia is to tailor your content for Web delivery.

Do not simply translate video and audio content to the computer screen.

Employ design guidelines and use the strength of computers to make content exciting and approachable.

References

American Memory from the Library of Congress, Retrieved on October 20, 2004 from: http://memory.loc.gov/ammem/index.html

Beggs, J. and Thede D. (2001). Designing Web Audio: Chapter 5: Introduction to Streaming Media. Retrieved October on 22, 2004 from:http://www.oreilly.com/catalog/sound/chapter/ch05.html

Nielsen, J. (1999). Video and Streaming Media. Retrieved on October 22, 2004 from:http://www.useit.com/alertbox/990808.html

Streaming media – Wikipedia, Retrieved on October 22, 2004 from:http://en.wikipedia.org/wiki/Streaming_media

Codec – Wikipedia, Retrieved on October 20, 2004 from:http://en.wikipedia.org/wiki/Codec

QuickTime – Wikipedia, Retrieved on October 20, 2004 from:http://en.wikipedia.org/wiki/QuickTime

Windows Media – Wikipedia, Retrieved on October 20, 2004 from:http://en.wikipedia.org/wiki/Windows_Media

Windows Media Audio – Wikipedia, Retrieved on October 20, 2004 from:http://en.wikipedia.org/wiki/Windows_Media_Audio

Windows Media Video – Wikipedia, Retrieved on October 20, 2004 from:http://en.wikipedia.org/wiki/Windows_Media_Audio