osc: Oscillogram

In tatters/soundgen: Sound Synthesis and Acoustic Analysis

Oscillogram

Description

Plots the oscillogram (waveform) of a sound on a linear or logarithmic scale (in dB). To get a dB scale, centers and normalizes the sound, then takes a logarithm of the positive part and a flipped negative part, which is analogous to "Waveform (dB)" view in Audacity. For more plotting options, check oscillo.

Usage

osc(
  x,
  samplingRate = NULL,
  scale = NULL,
  from = NULL,
  to = NULL,
  dynamicRange = 80,
  dB = FALSE,
  returnWave = FALSE,
  reportEvery = NULL,
  cores = 1,
  plot = TRUE,
  savePlots = NULL,
  main = NULL,
  xlab = NULL,
  ylab = NULL,
  ylim = NULL,
  bty = "n",
  midline = TRUE,
  maxPoints = 10000,
  width = 900,
  height = 500,
  units = "px",
  res = NA,
  ...
)

Arguments

x	path to a folder, one or more wav or mp3 files c('file1.wav', 'file2.mp3'), Wave object, numeric vector, or a list of Wave objects or numeric vectors
samplingRate	sampling rate of x (only needed if x is a numeric vector)
scale	maximum possible amplitude of input used for normalization of input vector (only needed if x is a numeric vector)
from, to	if NULL (default), analyzes the whole sound, otherwise from...to (s)
dynamicRange	dynamic range, dB. All values more than one dynamicRange under maximum are treated as zero
dB	if TRUE, plots on a dB instead of linear scale
returnWave	if TRUE, returns a log-transformed waveform as a numeric vector
reportEvery	when processing multiple inputs, report estimated time left every ... iterations (NULL = default, NA = don't report)
cores	number of cores for parallel processing
plot	if TRUE, plots the oscillogram
savePlots	full path to the folder in which to save the plots (NULL = don't save, ” = same folder as audio)
main	plot title
xlab, ylab	axis labels
ylim	override default amplitude scale for non-centered sounds
bty	box type (see '?par')
midline	if TRUE, draws a line at 0 dB
maxPoints	the maximum number of points to plot (speeds up the plotting of long audio files, but beware of antialiasing)
width, height, units, res	graphical parameters for saving plots passed to png
...	Other graphical parameters passed on to 'plot()'

Value

If returnWave = TRUE, returns the input waveform on the original or dB scale: a vector with range from '-dynamicRange' to 'dynamicRange'.

Examples

sound = sin(1:2000/10) *
        getSmoothContour(anchors = c(1, .01, .5), len = 2000)

# Oscillogram on a linear scale without bells and whistles, just base R
plot(sound, type = 'l')

# Oscillogram options with soundgen
osc(sound)             # linear
osc(sound, dB = TRUE)  # dB

# For numeric vectors, indicate samplingRate and scale (max amplitude)
osc(sound, samplingRate = 1000, scale = 100, dB = TRUE)

# Embellish and customize the plot
o = osc(sound, samplingRate = 1000, dB = TRUE, midline = FALSE,
        main = 'My waveform', col = 'blue', returnWave = TRUE)
abline(h = -80, col = 'orange', lty = 3)
o[1:10]  # the waveform in dB

## Not run: 
# Wave object
data(sheep, package = 'seewave')
osc(sheep, dB = TRUE)

# Plot a section
osc(sheep, from = .5, to = 1.2)

# for long files, reduce the resolution to plot quickly (careful: if the
# resolution is too low, antialiasing may cause artifacts)
osc(sheep, dB = TRUE, maxPoints = 2500)
osc(sheep, samplingRate = 5000, maxPoints = 100)

# files several minutes long can be plotted in under a second
osc('~/Downloads/speechEx.wav', maxPoints = 20000)

# saves oscillograms of all audio files in a folder
osc('~/Downloads/temp2', savePlots = '')

## End(Not run)

tatters/soundgen documentation built on Aug. 22, 2023, 4:24 p.m.