soundgen (version 1.8.2)

osc: 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,
  dynamicRange = 80,
  dB = FALSE,
  maxAmpl = NULL,
  samplingRate = NULL,
  returnWave = FALSE,
  plot = TRUE,
  xlab = NULL,
  ylab = NULL,
  ylim = NULL,
  bty = "n",
  midline = TRUE,
  maxPoints = 10000,
  ...
)

Arguments

x

path to a .wav file or a vector of amplitudes with specified samplingRate

dynamicRange

dynamic range of the oscillogram, dB

dB

if TRUE, plots on a dB instead of linear scale

maxAmpl

the maximum theoretically possible value indicating on which scale the sound is coded: 1 if the range is -1 to +1, 2^15 for 16-bit wav files, etc

samplingRate

sampling rate of x (only needed if x is a numeric vector, rather than a .wav file)

returnWave

if TRUE, returns a log-transformed waveform as a numeric vector

plot

if TRUE, plots the oscillogram

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)

...

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

# NOT RUN {
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 max amplitude
osc(sound, maxAmpl = 100, dB = TRUE)

# Embellish and customize the plot
o = osc(sound, dB = TRUE, samplingRate = 1000, 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 {
# audio file
data(sheep, package = 'seewave')
osc(sheep@left, samplingRate = [e-mail], dB = TRUE)

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

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