Audio

1
Audio

• Chapter 9

2
Objectives

• Discuss role of audio in computing and multimedia
• Describe how digital audio recording devices
  capture sound
• Explain sampling and how it relates to sound
  quality and file size

• Discuss importance of file compression
• Distinguish between audio file formats
• Describe software for working with audio in
  multimedia
• Describe audio devices for multimedia

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Audio in Multimedia

• In a multimedia production, sound and music
  are crucial in helping to establish moods and
  create environments.

Objective 1
4
Audio on PCs

• Many types of sounds are accessible with a PC.
  They include
• Music
• Sound effects
• Spoken narration
• Video soundtracks
• Real-time telephone conversations
• Operating system alerts and prompts

5
Digital Audio Recording

• Digital recording devices capture sound by
  sampling the sound waves.

Objective 2
6
Digital Audio Quality

• Quality and size of digital audio depends on
• The sampling rate
• Number of times per seconda recording device
  captures a segment of sound
• The sample size
• Aka audio resolution
• 8 or 16 bits
• more bits better sound

• The number of channels
• 1 monoaural
• 2 sterophonic
• 5 surround sound
• The time span of the recording
• How many seconds of music

Objective 3
7
What is streaming audio?

• Streaming audio plays as it reaches your PC,
  making it unnecessary to wait until the entire
  file is downloaded to the computer.

8
Audio File Formats

• An audio files format determines what files a
  PC can open and play, and how much space the file
  occupies on a disk. File formats include
• MP3
• WAV
• MIDI

Objective 4 5
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MP3 Format

• MP3 is a standard format for music files sent
  over the Internet. MP3s
• Use one of three MPEG standards for audio
  compression
• Can compress an audio file to about one-twelfth
  of the space it occupies on a CD with no
  significant loss of sound quality

Objective 5
10
WAV Format

• WAV is a standard for sound files on Windows
  and Macintosh PCs. WAVs
• Do not compress audio as much as MP3s
• Are generally used for sound effects and other
  small files

Objective 5
11
MIDI Format

• MIDI is a method and format for recording
  music from synthesizers and other electronic
  instruments. MIDIs
• Are created with a computer that has a sequencer
• Do not contain actual musical notes
• Do not contain sound waves or use sampling
• Are small and load quickly on a Web site

Objective 5
12
Future of Audio on the Web

• Improved quality
• Smaller files
• Surround sound
• Speech synthesis and voice recognition
• Accessibility applications

13
Audio Software for the PC

• Most new PCs come with some software and
  hardware for recording and managing audio files.
• Audio editing software allows you to edit audio
  files and convert them from one format to
  another.
• MIDI software includes programs for recording,
  storing, replaying, and editing MIDI files.
• Composition software allows you to create sheet
  music for many voices or instruments.

Objective 6
Download Audacity
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Audio Hardware Devices

• Audio hardware devices for the PC may include
• Audio or sound cards
• Speakers
• Microphones for voice input
• MIDI input devices
• CD/DVD burners

Objective 7
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Assignment

• Self Assessment Activity online
• Test Tomorrow
• Hands on activity
• Requirements
• Audacity download
• Windows Movie Maker
• Download audio file from internet
• Import to Audacity
• Add another track
• Play with Audacity to learn about it

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Assignment Day 2

• Chapter 9 written Test
• Do
• Activity 9-2 page 375-376
• Activity 9-4 page 379-380

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Assignment Day 3

• Page 209
• Applying Multimedia Skills 1- Selling a Product
• Must create script
• Include sound effects as well as words
• Can use music in background
• Use either Audacity or Movie Maker
• Use more than one track

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Assignment Day 4

• Finish Radio Ad
• Read Chapter 10