Apple Shake 4 - Manual (Page 287)

Chapter 9 Using the Audio Panel 287
A progress bar appears to show you how long this process takes.
Opening the Globals tab reveals the Audio parameter that has been created,
underneath the localParameters subtree. This parameter is now ready for use as an
expression from within other parameters in your project.
Create Curves Options
These parameters in the Create Curves subtree of the Audio Panel let you customize
how keyframe information is extracted from the audio waveform.
Update from Globals
Indicates if timing for the audio export should come from script globals or from the
audio tab. Click “update now” to read settings from the Globals tab.
Time Range
The frame range of the audio to be extracted.
Interval (frames)
A key is entered every N frames, controlled by the Interval parameter.
Type
This parameter defines how the volume of the audio in your project is analyzed.
• Peak means the generated value is the highest absolute value the waveform reaches
during that interval.
• RMS (“Root Mean Square”), on the other hand, uses the square root of the mean of
the squares on the absolute values of the waveform over the interval. In other words,
each absolute displacement value in the interval is squared, the average of all those
squared values is calculated, and its square root is taken as the representative value
for that interval. The RMS method is said to be more representative of the actual
perceived volume of an interval of digital audio.
Logarithmic (dB)
When deactivated, the returned value is the actual value from the audio file. The
sample values are normalized from -1.0 to 1.0, with 1.0 =0 dBFS. Therefore, the usual
range in this mode is 0.0 to 1.0. Values may exceed 1.0 if the audio is clipping
(exceeding 1.0, or 0 dBFS).
If “logarithmic” mode is on, the value generated is converted to a dB scale, normalized
linearly over 90 decibels from 0.0 to 1.0. A value of 0.0 would thus represent -90 dBFS
(or lower), and 1.0 would represent 0 dBFS.