Transcript Creating Web Documents - Purchase College Faculty Web Server

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