Convert input audio to video output representing frequency spectrum using Continuous Wavelet Transform and Morlet wavelet.

The filter accepts the following options:

size, s

Specify the video size for the output. For the syntax of this option, check the "Video size" section in the ffmpeg-utils manual. Default value is 640x512.

rate, r

Set the output frame rate. Default value is 25.

scale

Set the frequency scale used. Allowed values are:

• linear
• log
• bark
• mel
• erbs
• sqrt
• cbrt
• qdrt

Default value is linear.

iscale

Set the intensity scale used. Allowed values are:

• linear
• log
• sqrt
• cbrt
• qdrt

Default value is log.

min

Set the minimum frequency that will be used in output. Default is 20 Hz.

max

Set the maximum frequency that will be used in output. Default is 20000 Hz. The real frequency upper limit depends on input audio’s sample rate and such will be enforced on this value when it is set to value greater than Nyquist frequency.

imin

Set the minimum intensity that will be used in output.

imax

Set the maximum intensity that will be used in output.

logb

Set the logarithmic basis for brightness strength when mapping calculated magnitude values to pixel values. Allowed range is from 0 to 1. Default value is 0.0001.

deviation

Set the frequency deviation. Lower values than 1 are more frequency oriented, while higher values than 1 are more time oriented. Allowed range is from 0 to 10. Default value is 1.

pps

Set the number of pixel output per each second in one row. Allowed range is from 1 to 1024. Default value is 64.

mode

Set the output visual mode. Allowed values are:

magnitude

Show magnitude.

phase

Show only phase.

magphase

Show combination of magnitude and phase. Magnitude is mapped to brightness and phase to color.

channel

Show unique color per channel magnitude.

stereo

Show unique color per stereo difference.

Default value is magnitude.

slide

Set the output slide method. Allowed values are:

• replace
• scroll
• frame

direction

Set the direction method for output slide method. Allowed values are:

lr

Direction from left to right.

rl

Direction from right to left.

ud

Direction from up to down.

du

Direction from down to up.

bar

Set the ratio of bargraph display to display size. Default is 0.

rotation

Set color rotation, must be in [-1.0, 1.0] range. Default value is 0.