dot-spectrogram: Spectrogram per sound

In soundgen: Sound Synthesis and Acoustic Analysis

Spectrogram per sound

Description

Internal soundgen function called by spectrogram and analyze.

Usage

.spectrogram(
  audio,
  dynamicRange = 80,
  windowLength = 50,
  step = windowLength/2,
  overlap = NULL,
  specType = c("spectrum", "reassigned", "spectralDerivative")[1],
  logSpec = TRUE,
  rasterize = FALSE,
  wn = "gaussian",
  zp = 0,
  normalize = TRUE,
  smoothFreq = 0,
  smoothTime = 0,
  qTime = 0,
  percentNoise = 10,
  noiseReduction = 0,
  output = c("original", "processed", "complex", "all")[1],
  specManual = NULL,
  plot = TRUE,
  osc = c("none", "linear", "dB")[2],
  heights = c(3, 1),
  ylim = NULL,
  yScale = "linear",
  contrast = 0.2,
  brightness = 0,
  blur = 0,
  maxPoints = c(1e+05, 5e+05),
  padWithSilence = TRUE,
  colorTheme = c("bw", "seewave", "heat.colors", "...")[1],
  col = NULL,
  extraContour = NULL,
  xlab = NULL,
  ylab = NULL,
  xaxp = NULL,
  mar = c(5.1, 4.1, 4.1, 2),
  main = NULL,
  grid = NULL,
  width = 900,
  height = 500,
  units = "px",
  res = NA,
  internal = NULL,
  ...
)

Arguments

audio	a list returned by readAudio
dynamicRange	dynamic range, dB. All values more than one dynamicRange under maximum are treated as zero
windowLength	length of FFT window, ms (multiple values in a vector produce a multi-resolution spectrogram)
step	you can override overlap by specifying FFT step, ms - a vector of the same length as windowLength (NB: because digital audio is sampled at discrete time intervals of 1/samplingRate, the actual step and thus the time stamps of STFT frames may be slightly different, eg 24.98866 instead of 25.0 ms)
overlap	overlap between successive FFT frames, %
specType	plot the original FFT ('spectrum'), reassigned spectrogram ('reassigned'), or spectral derivative ('spectralDerivative')
logSpec	if TRUE, log-transforms the spectrogram
rasterize	(only applies if specType = 'reassigned') if TRUE, the reassigned spectrogram is plotted after rasterizing it: that is, showing density per time-frequency bins with the same resolution as an ordinary spectrogram
wn	window type accepted by ftwindow, currently gaussian, hanning, hamming, bartlett, blackman, flattop, rectangle
zp	window length after zero padding, points
normalize	if TRUE, scales input prior to FFT
smoothFreq, smoothTime	length of the window for median smoothing in frequency and time domains, respectively, points
qTime	the quantile to be subtracted for each frequency bin. For ex., if qTime = 0.5, the median of each frequency bin (over the entire sound duration) will be calculated and subtracted from each frame (see examples)
percentNoise	percentage of frames (0 to 100%) used for calculating noise spectrum
noiseReduction	how much noise to remove (non-negative number, recommended 0 to 2). 0 = no noise reduction, 2 = strong noise reduction: spectrum - (noiseReduction * noiseSpectrum), where noiseSpectrum is the average spectrum of frames with entropy exceeding the quantile set by percentNoise
output	specifies what to return: nothing ('none'), unmodified spectrogram ('original'), denoised and/or smoothed spectrogram ('processed'), or unmodified spectrogram with the imaginary part giving phase ('complex')
specManual	manually calculated spectrogram-like representation in the same format as the output of spectrogram(): rows = frequency in kHz, columns = time in ms
plot	should a spectrogram be plotted? TRUE / FALSE
osc	"none" = no oscillogram; "linear" = on the original scale; "dB" = in decibels
heights	a vector of length two specifying the relative height of the spectrogram and the oscillogram (including time axes labels)
ylim	frequency range to plot, kHz (defaults to 0 to Nyquist frequency). NB: still in kHz, even if yScale = bark, mel, or ERB
yScale	scale of the frequency axis: 'linear' = linear, 'log' = logarithmic (musical), 'bark' = bark with hz2bark, 'mel' = mel with hz2mel, 'ERB' = Equivalent Rectangular Bandwidths with HzToERB
contrast	controls the sharpness or contrast of the image: <0 = decrease contrast, 0 = no change, >0 increase contrast. Recommended range approximately (-1, 1). The spectrogram is raised to the power of exp(3 * contrast)
brightness	makes the image lighter or darker: <0 = darker, 0 = no change, >0 = lighter, range (-1, 1). The color palette is preserved, so "brightness" works by capping an increasing proportion of image at the lightest or darkest color. To lighten or darken the palette, just change the colors instead
blur	apply a Gaussian filter to blur or sharpen the image, two numbers: frequency (Hz), time (ms). A single number is interpreted as frequency, and a square filter is applied. NA / NULL / 0 means no blurring in that dimension. Negative numbers mean un-blurring (sharpening) the image by dividing instead of multiplying by the filter during convolution
maxPoints	the maximum number of "pixels" in the oscillogram (if any) and spectrogram; good for quickly plotting long audio files; defaults to c(1e5, 5e5); does not affect reassigned spectrograms
padWithSilence	if TRUE, pads the sound with just enough silence to resolve the edges properly (only the original region is plotted, so the apparent duration doesn't change)
colorTheme	black and white ('bw'), as in seewave package ('seewave'), matlab-type palette ('matlab'), or any palette from palette such as 'heat.colors', 'cm.colors', etc
col	actual colors, eg rev(rainbow(100)) - see ?hcl.colors for colors in base R (overrides colorTheme)
extraContour	a vector of arbitrary length scaled in Hz (regardless of yScale, but nonlinear yScale also warps the contour) that will be plotted over the spectrogram (eg pitch contour); can also be a list with extra graphical parameters such as lwd, col, etc. (see examples)
xlab, ylab, main, mar, xaxp	graphical parameters for plotting
grid	if numeric, adds n = grid dotted lines per kHz
width, height, units, res	graphical parameters for saving plots passed to png
internal	a long list of stuff for plotting pitch contours passed by analyze()
...	other graphical parameters

soundgen documentation built on Dec. 1, 2025, 9:08 a.m.