Digitizing Audio

Audio is an important component of most media productions. Like video, analog sound must be digitized, or sampled, to be used along with digitized videotape. Fortunately, audio is not nearly as hard to digitize as is video. Sampling analog sound breaks up the sound into discrete frequencies. There are two steps in digitizing audio--setting the audio level controls to avoid distortion and setting the audio resolution or quality.

 

The quality (or resolution) of digitized audio and the size of the audio file depend on the sampling rate and bit depth of the audio. The sampling rate, similar to the frame rate for digitizing video, measures the number of frequencies into which the sound is broken. The bit depth, similar to color depth, measures the number of tones per sample. The higher the sampling rate and bit depth, the better the sound quality. Think of audio sampled at 11 kHz and 8-bit resolution as similar to mono sound, and audio sampled at 22 kHz and 16-bit resolution (which requires twice the file size for the audio clip) as similar to stereo or CD sound. CD audio is normally digitized at 44 kHz and 16-bit resolution.

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