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Creating Web Documents. alt attribute Good and bad uses of ‘multimedia’ Sound files Homework: Discuss with me AND post announcement of Project II. Forms & JavaScript next. Browser kerfuffle. http://www.w3.org/Style/CSS/ Look at this using IE versus Netscape. Alternative to images.
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Creating Web Documents alt attribute Good and bad uses of ‘multimedia’ Sound files Homework: Discuss with me AND post announcement of Project II. Forms & JavaScript next
Browser kerfuffle • http://www.w3.org/Style/CSS/ • Look at this using IE versus Netscape
Alternative to images <img src="bird.gif" alt="bird"> • Browser will display "bird" if graphics turned off, also when mouse over image. Why? • Way to offer more information • Step to making Web site ADA compliant (screen reader program will 'say' the alt text)
Sound • Spoken word • Music • Special effects • Expectations are that Web sites on topics relating to sound must have sound! • What about other Web sites?
Sound • Sound is recorded by a process called sampling (but sampling also has another meaning): • Measure the electrical signal picked up by microphone at [some] interval • Frequency (measured in times/second = Hz for Hertz) and • Amount of information (bits) per measurement • More information (more bits) and sampling more often is better but means larger files
Sound • Find Sound Recorder on your computers
Sound Recorder • Click File/Properties/Convert Now • Note pre-set Telephone quality, Radio, or CD settings.
Digital Audio • Sound Recorder produces a wav file. Wav files are used on Web sites. • This can be changed to other formats using other software products. • Other products for recording (and mixing) often start by creating wav files. • Two other, important formats for the Web are • Mpg = ‘mpeg’, a compressed format • Streaming audio, downloads and plays in packets, so sound starts very quickly.
Playing a wav file • Adding a link <a href=“sound.wav”>Hear this </a> Advantages: Client (site visitor) makes decision to do download Works on most platforms • But what if you want to have sound automatically (without user action): See text for embed and bgsound • Problems with different browsers
MIDI • Musical Instrument Digital Interface is the standard for connecting instruments (for example, keyboards), computers, synthesizers, and software (sequencers) • MIDI is not recorded sound. • MIDI is set of instructions, such as • Start note (numbered according to keys on piano) at specific velocity on given channel • Stop note • Set up instrument (= timbre) on channel
Other possibilities • Integrate sound into a Flash movie • Creating Dynamic Web Documents course • Integrate sound into Director/Shockwave • ?
Homework • Read on sound and other ‘multimedia’ in HTML text • Make posting and read postings on multimedia • Contribute to other Forums • Talk with me AND make announcement on Project II