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Audio Analyzer

Brief Description

Uses a spectral analysis of the Audio Source to return the value of a selected frequency range, using the Frequency Weights curve to perform a weighted average. When selecting the Frequency Weights parameter, the Curve Editor displays the audio spectrum so you can visualize the frequencies distribution of the Audio signal. When the curve is at 0, the corresponding frequencies are ignored from the resulting value, while frequencies with a higher weight are more prominent in the resulting value. The curve allows you to easily extract e.g only the low frequencies or any specific frequency ranges.

Controls

Parameter / Script Name Type Default Function
Enabled / enabled Boolean On
Audio Source / source Audio -
Channel / channel_index Choice Average Channels Whether to use a specific audio channel to compute the spectrum or to average the channels
- Average Channels
Temporal Radius / temporal_window_radius Float 0.1 Define the temporal window radius over which the spectrum is calculated. The higher the value, the smoother the spectrum will be, but to the cost of a longer calculation time. Note that using a large temporal window can make the past and future audio participate in the output, which can lead to a perceived delay or advance. N.B: the radius of the window is internally clamped so that it can never be smaller than the minimum number of samples required by Bands Count. e.g: If the audio is at 48Khz and Band Count is 8192, the minimum temporal radius is 48000/8192/2, which is 0.085
Bands Count / nb_bands Choice 1024 The number of frequency ranges (or Bands) calculated in output. Note that frequencies always vary between 0 and half the sample rate of the audio signal.
- 1024
- 2048
- 4096
- 8192
- 16384
- 32768
Frequency Weights / weights A curve defining weights applied to each frequencies. Use the Curve Editor to edit the curve based on the visual representation of the audio spectrum. Values of 0 cancel the frequency from participating in the output, whereas higher values enhance the frequencies
Axis Type / axis_type Choice Logarithmic Whether the spectrum is displayed in a logarithmic or linear scale. Since most frequencies are rather low, setting it to logarithmic gives more room to the lower frequencies. Note that the Frequency curve is not adapted when changing the axis type.
- Linear
- Logarithmic
Threshold / threshold Float 0.01 Frequencies with an amplitude below this value will not be taken into account in the resulting weighted mean
Multiplier / multiplier Float 1 Applies a post multiplier to the output value
Follow Time / followTime Boolean On When checked, the audio is sampled at the local time of the pointed audio source. When unchecked, the audio is sampled at the time of this layer