The document discusses digital audio and animation formats for use on the web. It provides details on common audio formats like WAV, MP3, MIDI and animation formats like GIF, SWF, and describes their advantages and disadvantages. Streaming media allows compressing and transmitting audio over the internet by breaking it into packets. Common streaming formats are RealAudio, Windows Media. Animation is possible due to persistence of vision and phi phenomena.
2. CMS Content Updating
In this chapter, you will learn:
o Define what is “digital audio”
o Identify the various sound formats and its
characteristics
o Describe the advantages and disadvantages of the
various formats across platforms.
o Define what “digital animation”
o Identify the characteristics and file extensions of
various animation formats.
o Describe the advantages and disadvantages of the
various formats across platforms.
3. Digital Sound
A sound file format is simply a recognized
methodology for organizing the digitised
sound’s data bits and bytes into a data file.
Audio in Macintosh
o On Macintosh, digitized sound is stored as data
files (file extension .AIF or .SDII
Audio in Windows
o Microsoft has established a common audio file
format called the wave audio format (wav)
4. Digital Sound
Working with audio in the Internet
o Download the entire audio file
o Let the audio file streams into the computer
5. Digital Sound
Musical Instrument Digital Interface –
MIDI Format
o It is not a digital audio format but a form of music
notation
o Both Mac and Windows make use of MIDI files
o A MIDI interface is built into many sound cards of
the PC
o MIDI sounds are typically stored in files with the
.MID extension
6. Digital Sound
Advantages of MIDI Format
o it is a near universal playback
o easy integration into existing HTML pages
o MIDI sizes are relatively small (2 KB and 25 KB)
7. Digital Sound
Disadvantages of MIDI Format
o it uses entirely different method of producing
sound
o it is basically a music notation and not a storage
format for digitized audio
o it is limited to jingles, instrumental tunes and
ambient synthesizer background sounds
8. Digital Sound
Windows WAVE Format (.wav)
o Developed by Microsoft and IBM and is the
common audio file format used for Windows.
o may be compressed or uncompressed
o one of the common formats used to store and
play audio data
o it doesn't address compression
9. Digital Sound
Aiff Format (.aiff, .aif)
o stands for Audio Interchange File Format and
was developed by Apple for storage of sounds
o a flexible file format
o allows the specification of arbitrary sampling
rates, sample size, number of channels, and
application-specific format chunks.
10. Digital Sound
Snd Format (.snd)
o The SND (Sound ) was developed by Apple
Computer Inc.
o SND files are not cross-platform
o Not supported by all web browser
11. Digital Sound
MP3 Format (.mp3)
o Uses a compression ratio capable of bringing file
sizes down to approximately a megabyte a
minute
o uses a lossy compression scheme
o MP3 stands for MPEG 1 layer 3
o usually 10-12 times smaller than normal 44Khz
16-bit stereo wav files
o MP3 files are the sound part of the MPEG video
format
12. Digital Sound
RealAudio Fomat (.rm, ram)
o developed for the Internet by Real Media
o also supports video
o features true streaming technology
o allows streaming of audio (on-line music, Internet
radio) with low bandwidths
o reduces significant file size reductions
13. Digital Sound
Windows Media Audio Format (.wma)
o is a relatively late entry into the field of
proprietary audio formats
o performs very good at lower bit-rates
o produce quality indistinguishable from the
original CD at 128 kbps
o supported by most full-featured player programs
o is royalty-free when incorporated into software
that runs on the Windows platform
o ASF is Microsoft's specification for streaming
14. Compression
MPEG-1 Digital Audio Compression
o Layer I – not commonly used and seldom
discussed.
o Layer II – used in DVD audio.
o Layer III – commonly called MP3. It is a popular
format for compressed music on the Internet.
16. Compression
Dolby Digital Audio Compression
o also known as AC-3
o chosen audio compression for the new digital
television transmission
o allows up to 5.1 channels of discrete digital audio
to be compressed
17. Audio on the Web
Benefits
o communicate ideas through informative
dialogue, narration and voice content
o improve site navigation with sound effects
o enliven the entertainment pages
o provide background music to your
presentation
o online music sales and distribution of digitized
audio clips
18. Streaming Media
The Streaming Media is a powerful technical
innovation
1. Compress a digital audio file
2. Breaking it into small packets
3. Sent one after another over the internet.
4. When the packets reached their destination
5. They are decompressed and re-assembled
6. Played by the user’s system.
19. Streaming Media Formats
The widely used formats are:
o RealNetworks’ RealAudio
o MP3
o Adobe Flash
o Microsoft’s Window Media
o Apple’s QuickTime
21. Streaming Media Formats
Animation is possible because of a biological
phenomenon known as persistence of vision
and a psychological phenomenon called phi
22. Streaming Media Formats
Tweening
o The series of frames in between the keyframes
Frame Rate
o is the frequency (rate) at which an imaging device
produces unique consecutive images called
frames.
23. Animation File Format
Fli/Flc Format
FLC - Animator Pro Flic Files
o This is the main animation file format created by
Animator Pro.
FLI - Original Animator Flic Files
o limited to 320x200 resolutions
o file structure is very similar to that of a FLC file
24. Animation File Format
GIF89
o allows multiple images to be put into a single file
and then displayed as an animation in a Web
browser
o Allows for transparency
25. Animation File Format
SWF (Small Web Format or Shockwave Flash)
o was designed to deliver vector graphics and
animation over the Internet
o designed to meet the following goals:
• On-screen Display
• Network Delivery
• Simplicity
• File Independence
• Scalability
• Speed
26. Animation File Format
MNG
o is short for Multiple-image Network Graphics
o designed to replace the animated GIF
o designed to animate a series of JPG images in as
complicated a way as possible
27. Animation for the Web
HTML makes no provision for animation
Animation using:
o GIF89
o Adobe SWF
o Java Script
