IT2032PAContent Management System (CMS) Nitec in Social Media & Web Technology
CMS Content UpdatingIn 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.
Digital SoundA sound file format is simply a recognizedmethodology for organizing the digitisedsound’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)
Digital SoundWorking with audio in the Internet o Download the entire audio file o Let the audio file streams into the computer
Digital SoundMusical 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
Digital SoundAdvantages 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)
Digital SoundDisadvantages 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
Digital SoundWindows 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 doesnt address compression
Digital SoundAiff 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.
Digital SoundSnd 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
Digital SoundMP3 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
Digital SoundRealAudio 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
Digital SoundWindows 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 Microsofts specification for streaming
CompressionMPEG-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.
CompressionMPEG-2 Digital Audio Compression o adds multiple channels o provides backward compatibility with MPEG-1 decoders
CompressionDolby 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
Audio on the WebBenefits 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
Streaming MediaThe Streaming Media is a powerful technicalinnovation 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.
Streaming Media FormatsThe widely used formats are: o RealNetworks’ RealAudio o MP3 o Adobe Flash o Microsoft’s Window Media o Apple’s QuickTime
Digital AnimationAnimation makes static presentation come alive.
Streaming Media FormatsAnimation is possible because of a biologicalphenomenon known as persistence of visionand a psychological phenomenon called phi
Streaming Media FormatsTweening o The series of frames in between the keyframesFrame Rate o is the frequency (rate) at which an imaging device produces unique consecutive images called frames.
Animation File FormatFli/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
Animation File FormatGIF89 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
Animation File FormatSWF (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
Animation File FormatMNG 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
Animation for the WebHTML makes no provision for animation Animation using: o GIF89 o Adobe SWF o Java Script
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