Coloring the Audio Waveform Display

The most common visual representation of audio is its waveform display, which is a graph showing the amplitude (loudness) over time. It indicates when the audio is loud or soft, but provides no information about how the audio sounds. Here, colors are derived automatically from the frequency content of audio and used to paint the waveform display, making it possible to see the audio!

In rough terms, shades of red are used for high-pitched sounds; greens and blues are used mostly for mid-range sounds; and bass sounds are represented by dark colors. Similar sounds are indicated by similar colors, and changes in sound are shown as changes in color. The coloring makes the waveform display tremendously more useful.

See examples of colored and uncolored waveform displays in the Sound Gallery. You can also download a QuickTime Demo (3.3 MB).

Colored waveform display showing an excerpt from Kenny G's Songbird