Apple Motion 4 - Manual (Page 1354)

Parameters in the Inspector
Source Audio: Sets the audio track from which to read audio data. Can be set to any
single audio track in the project, or the Master track. Either drag an audio clip or a video
clip with audio into the Source Audio well, or use the pop-up menu to choose a source
for audio analysis.
Note: In order for the Audio Parameter behavior to have an effect on an object, audio
must be present in the Timeline at the position of the behavior.
Respond To: A pop-up menu that sets the type of audio data analysis to perform. Choose
either Amplitude or Transients. If set to Amplitude, the behavior responds to peak values
of a particular frequency. If set to Transients, the behavior responds to rapid changes in
frequency.
Graph Range: A pop-up menu that sets the initial range of frequency values to be analyzed
by the behavior. There are four menu options: All Frequencies, Bass, Mid, or Treble. The
choice of display affects the frequency range of the Low Frequency and High Frequency
parameters below.
Audio Graph: Displays a visual representation of the Source Audio data analyzed by the
behavior per frame.
During playback initiated by the Play button beneath the Audio Graph, the selected
Source Audio data is displayed. If audio analysis is being performed, progress is displayed
in the Audio Graph area as shown below.
The values of Low Frequency, High Frequency, Floor, and Ceiling can be set by dragging
the small triangles along the bottom or right side of the graph, or set numerically using
the four sliders underneath the graph to isolate certain frequencies and values for analysis.
Low Frequency: Sets the low frequency threshold of audio analysis. Only audio frequencies
above this value will be analyzed. Values range from 1 Hz to 22,050 Hz.
1354 Chapter 20 Working with Audio