dot-segment: Internal soundgen function

.segmentR Documentation

Internal soundgen function

Description

A helper function called internally by segment() for segmenting a single sound.

Usage

.segment(
  audio,
  shortestSyl = 40,
  shortestPause = 40,
  method = c("env", "spec", "mel")[3],
  propNoise = NULL,
  SNR = NULL,
  noiseLevelStabWeight = c(1, 0.25),
  windowLength = 40,
  step = NULL,
  overlap = 80,
  reverbPars = list(reverbDelay = 70, reverbSpread = 130, reverbLevel = -35,
    reverbDensity = 50),
  interburst = NULL,
  peakToTrough = SNR + 3,
  troughLocation = c("left", "right", "both", "either")[4],
  maxDur = 30,
  saveAudio = NULL,
  addSilence = 50,
  plot = FALSE,
  plotname = "",
  savePlots = NULL,
  main = NULL,
  xlab = "",
  ylab = "Signal, dB",
  showLegend = FALSE,
  width = 900,
  height = 500,
  units = "px",
  res = NA,
  maxPoints = c(1e+05, 5e+05),
  specPlot = NULL,
  contourPlot = list(lty = 1, lwd = 2, col = "green"),
  sylPlot = list(lty = 1, lwd = 2, col = "blue"),
  burstPlot = list(pch = 8, cex = 3, col = "red"),
  ...
)

Arguments

audio

a list returned by readAudio

shortestSyl

minimum acceptable length of syllables, ms

shortestPause

minimum acceptable break between syllables, ms (syllables separated by shorter pauses are merged)

method

the signal used to search for syllables: 'env' = Hilbert-transformed amplitude envelope, 'spec' = spectrogram, 'mel' = mel-transformed spectrogram (see tuneR::melfcc)

propNoise

the proportion of non-zero sound assumed to represent background noise (note that complete silence is not considered, so padding with silence won't affect the algorithm)

SNR

expected signal-to-noise ratio (dB above noise), which determines the threshold for syllable detection. The meaning of "dB" here is approximate since the "signal" may be different from sound intensity

noiseLevelStabWeight

a vector of length 2 specifying the relative weights of the overall signal level vs. stability when attempting to automatically locate the regions that represent noise. Increasing the weight of stability tends to accentuate the beginning and end of each syllable.

windowLength

length of FFT window, ms

step

you can override overlap by specifying FFT step, ms (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, %

reverbPars

parameters passed on to reverb to attempt to cancel the effects of reverberation or echo, which otherwise tend to merge short and loud segments like rapid barks

interburst

minimum time between two consecutive bursts (ms). Defaults to the average detected (syllable + pause) / 2

peakToTrough

to qualify as a burst, a local maximum has to be at least peakToTrough dB above the left and/or right local trough(s) (controlled by troughLocation) over the analysis window (controlled by interburst). Defaults to SNR + 3 dB

troughLocation

should local maxima be compared to the trough on the left and/or right of it? Values: 'left', 'right', 'both', 'either'

maxDur

long files are split into chunks maxDur s in duration to avoid running out of RAM; the outputs for all fragments are glued together, but plotting is switched off. Note that noise profile is estimated in each chunk separately, so set it low if the background noise is highly variable

saveAudio

full path to the folder in which to save audio files (one per detected syllable)

addSilence

if syllables are saved as separate audio files, they can be padded with some silence (ms)

plot

if TRUE, produces a segmentation plot

savePlots

full path to the folder in which to save the plots (NULL = don't save, ” = same folder as audio)

xlab, ylab, main

main plotting parameters

showLegend

if TRUE, shows a legend for thresholds

width, height, units, res

parameters passed to png if the plot is saved

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)

specPlot

a list of graphical parameters for displaying the spectrogram (if method = 'spec' or 'mel'); set to NULL to hide the spectrogram

contourPlot

a list of graphical parameters for displaying the signal contour used to detect syllables (see details)

sylPlot

a list of graphical parameters for displaying the syllables

burstPlot

a list of graphical parameters for displaying the bursts

...

other graphical parameters passed to graphics::plot


soundgen documentation built on Aug. 14, 2022, 5:05 p.m.