Chapter Concepts

Multimedia for the Web: Creating Digital Excitement

Multimedia Element — Sound

Chapter 8 2Multimedia for the Web

Discuss the Use of Sound on the WebUnderstand the Basic Principles of SoundExamine Digital Audio SourcesExplore Digital Audio SoftwareDiscover Audio File Formats for the Web

Chapter Concepts


The element of sound can be important to achieve the goals of a multimedia Web siteSound adds another dimensionIf improperly created, sound files can take too much time to download

Introduction

Chapter 8

Introduction

4Multimedia for the Web


Streaming audio: the sound file will begin playing after part of the file is downloadedTo help ensure effectiveness, it is important to incorporate sound files that are high quality, appropriate, and consistent with the goals of the multimedia Web site

Introduction


Discuss the Use of Soundon the Web

Web has made it very easy for users to purchase and download music files directly from online music storesEntertainment and game industry has spurred the growth of computers with multimedia capabilities


Web sites designed for entertainment have background music that sets the mood to light and cheery, or dark and drearyAudio can either be synched with the occurrence of other objects in the production, or it can serve as a trigger when clicked



Providing controls (such as skip, pause, mute, volume adjustment, etc.) is an effective way of keeping users involved and motivatedThe decision to incorporate sound into a multimedia Web site should have solid reasoning behind it



Sounds are either content sounds or ambient soundsContent sounds furnish information– Narration, dialogue are content sounds

Ambient sounds reinforce messages and set the moodMany splash screens or intro pages use background music to set a mood



When you speak, vibrations, called sound waves, are createdThese sound waves have a recurring pattern; an analog wave pattern called a waveform

Understanding the BasicPrinciples of Sound


Amplitude: Distance between the valley and the peak of a waveformDecibel (dB): Smallest variation in amplitude detected by the human earFrequency: Number of peaks that occur in one second measured by the distance between the peaks



Digitizing or Sound Sampling: The process of converting analog soundto numbersDigital Audio: An analog sound that has been converted to numbers


Chapter 8

Sound sampling



Two factors that determine sound quality are sample rate and resolutionSample Rate:– Number of waveform samples per second

or the number of times the sample is taken– Measured in kilohertz, with 11 kHz, 22

kHz, and 44 kHz being the most common sampling rates

Sound Quality


Resolution:– Number of binary bits processed for

each sound wave– Sometimes referred to as sample size– As the number of bits used to sample

the sound increases, the range and the quality of the sound also improves

Sound Quality


Mono versus Stereo SoundMono sounds: Flat and unrealistic compared to stereo soundsStereo sounds: Much more dynamic and lifelikeMono sound files are sometimes a more appropriate choice on the Web where storage and transfer are major concerns


Web Audio: Downloaded or streamedDownloaded audio file must be entirely saved to the user’s computer before it can be playedStreaming: More advanced process that allows sound file to be played as it is downloading; before entire file is transferred to the user’s computer

Downloaded versus Streamed


Compression: Technique that mathematically reduces size of a fileBeneficial for storing and transferring sound filesType of Compression applied impacts quality of sound file and file size

Compression


Clip audio gives access to prerecorded digital audio clips of music and sound effects

Examine Digital Audio Sources


Most of the sound on CDs has been sampled at almost 45,000 samples per second, which is very high qualityBe sure to carefully read the licensing agreements that come with clip audio

Examine Digital Audio Sources


In addition to using prerecorded audio files, you can record, digitize, and process your own sound files

Producing Digital Audio


PlanningProper planning is critical if sound is to be incorporated into multimedia Web siteIf the Web site is interactive, flowcharts should distinguish between which sounds are played as users make different choices


Minimally, a sound card and software program are needed to digitize soundThe sound card samples or digitizes the sound based on the sample rate (11, 22, or 44 kHz) and resolution (8- or 16-bit), and then produces the digital approximation of the analog signal

Recording


Microphones translate analog signals into electrical impulsesAn analog-to-digital converter (ADC), converts the electrical impulses to numbers that can be stored, understood, and manipulated by a microprocessor

Recording


MIDI: Standard format agreed on by the major manufacturers of musical instrumentsMIDI standard was established so musical instruments can communicate sound information with one another

Recording


RecordingTo communicate, MIDI instruments have “in” and “out” ports that enable them to be connected to another MIDI-ready device


ProcessingToday’s computers and synthesizers make it possible for the average person to produce high quality, relatively inexpensive recorded sound and musicPieces of sound files may need to be copied and moved or several sound files may need to be mixed and spliced together


AssemblingSociety of Motion Picture and Television Engineers (SMPTE) was developed to provide frame-accurate video and audio dataBy using professional SMPTE codes, beats of music can be set to match changes in video for all standard video frame rates


DeliveringTo play sound on a computer system, the user needs a sound card and speakers, or a headsetThe digital audio file is sent through a digital-to-analog converter (DAC) so that it can be heardImportant to test sounds under a variety of different conditions


Explore Digital Audio Software

Traditional sound studio equipment is utilized to record, mix, edit audio; costs tens of thousands of dollarsWith sound editing and mixing software,sound files can be produced for muchless money



In the sound editing and mixing industry, there are a number of high-quality licensed and shareware packages worth mentioningBIAS: Berkley Integrated Audio Software (BIAS); a leader in developing solutions for sound editing and mixing



Peak: Leading digital audio editor for Macintosh platform; ideal formanipulating sound filesSony: Leading developer and marketer of digital media and Internet software tools



Sound Forge: Similar to Peak, but designed for Windows platform– Set the quality of sound file including

sample rate, the resolution or sample size, file to be mono or stereo

Vegas: Frame-by-frame audio and video synchronization; high-quality streaming media, multitrack recording



ACID: music production software offers sound professionals freedom to create custom musicDigidesign Pro Tools: world’s leading nonlinear audio editing workstation and solutions



Pro Tools: most powerful and popular high-end audio solution on the marketAdobe Audition: formerly Cool Edit; digital audio software package that is comprehensive, yet easy to learn– Includes extensive top-quality digital

effects and it can mix multiple tracks


Discover Audio File Formats for the Web

All three media players (QuickTime, RealPlayer, Windows Media Player):– Equipped to open and display most

popular audio file formats– Possess the ability to play live

streaming audioQuickTime and RealPlayer: best choices for streaming media



Sound file formats include:– AAC (Advanced Audio Coding):

MPEG-4; format of choice for Web– AIFF or AIF (Audio Interchange File

Format): Macintosh waveform format



Sound file formats include:– AB (Audio/Basic): Sun audio format

developed by Sun Microsystems to Play on Unix, NeXT, and Sun Sparc workstations

– EA (Emblaze Audio): Sound format developed specifically for Internet by GEO for its Emblaze products



– MIDI (Musical Instrument Digital Interface): Internationally accepted file format for storing MIDI data

– MP3 (MPEG—Audio Layer 3): Open standard technology uses file compression to create near-CD quality audio files



– Real formats (RA, RAM, RM): Excellent compression, incredibly popular, widespread support for streaming audio

– SWF: compressed Macromedia Flash or Shockwave Flash file type designed for animation



– WAV: Waveform format; Commonly used, supported format on Windows

– WMA (Windows Media Audio): Powerful compression technology delivering audio and video quality at any bit rate

Chapter 8

Web-based audio file formats



Discuss the Use of Sound on the WebUnderstanding the Basic Principles of SoundSound QualityMono versus Stereo SoundDownloaded versus Streamed

Summary


CompressionExamine Digital Audio Sources Producing Digital AudioPlanningRecording

Summary


ProcessingAssembling DeliveringExplore Digital Audio SoftwareDiscover Audio File Formats for the Web

Summary

Documents

Chapter Concepts