CHAPTER 4: SOUND

1. Audio file formats

1.1. Professional sound -reduce space but reliability -space can be conserved

1.2. Inexpensive media -prevent hard disk from being overloaded -equipment and standards must be in accordance with requirements

1.3. Audio CDs -the Red Book -16 bits and 44.1KHz

1.4. Sound for your mobile

1.5. Sound for the internet

2. Adding sound to multimedia projects

2.1. Digital audio or MIDI data should be selected on the basis of the location and time of use

2.2. -Create or purchase source material -Edit the sounds to fit your project -Test sounds to timed properly

3. Introduction to Sound

3.1. Sound is the waves of pressure created by vibrations in the air

3.2. Vary in: - amplitude - frequency - pitch

3.3. "Acoustics" in physics

4. Digital Audio

4.1. DIGITAL AUDIO DATA stored in the form of samples

4.2. SAMPLES - the amplitude (loudness) of sound

4.3. Quality of digital recording depends on sampling rate (frequency) -samples taken per second

4.4. Digital audio is DEVICE INDEPENDENT

4.5. Quantization - value of sample rounded off to the nearest integer

4.6. Size of monophonic digital recording = sampling rate x (bit resolution/8) x1

4.7. Size of stereo recording = sampling rate x duration of recording in seconds x (bit resolution/8) x 2

5. MIDI Audio

5.1. Can be changed w/o affecting pitch of music or degrading audio quality

5.2. Requires knowledge of music theory

5.3. Stored in numeric form

5.4. Not digitized sound

5.5. device dependent

6. Recording and editing digital audio

6.1. Multimedia sound is either digitally recorded audio or MIDI music

6.2. Macintosh - AIFF/AIFC Windows - WAV files

6.3. MP3 - saves space MP4 - audio and video streamed together ACC - Apple's iTunes store