Multimedia Production

MULTIMEDIA PRODUCTION 4(1+3)

Lesson 13: Multimedia Building Blocks - Audio

Preparing digital audio files

Preparing digital audio files is fairly straight forward using analog source materials in which music or sound effects that have been recorded on analog media such as cassette tapes.

• The first step is to digitize the analog material and recording it onto a computer readable digital media. It is necessary to focus on two crucial aspects of preparing digital audio files:

• Balancing the sound quality against available RAM and Hard disk resources.
• Setting proper recording levels to get a good, clean recording.

Remember that the sampling rate determines the frequency at which samples will be drawn for the recording. Sampling at higher rates more accurately captures the high frequency content of your sound. Audio resolution determines the accuracy with which a sound can be digitized.

Formula for determining the size of the digital audio

Monophonic	=	Sampling rate * duration of recording in seconds * (bit resolution / 8) * 1
Stereo	=	Sampling rate * duration of recording in seconds * (bit resolution / 8) * 2

• The sampling rate is how often the samples are taken.
• The sample size is the amount of information stored. This is called as bit resolution.
• The number of channels is 2 for stereo and 1 for monophonic.
• The time span of the recording is measured in seconds.