analyze: Acoustic analysis

View source: R/analyze.R

analyzeR Documentation

Acoustic analysis


Acoustic analysis of one or more sounds: pitch tracking, basic spectral characteristics, formants, estimated loudness (see getLoudness), roughness (see modulationSpectrum), novelty (see ssm), etc. The default values of arguments are optimized for human non-linguistic vocalizations. See vignette('acoustic_analysis', package = 'soundgen') for details. The defaults and reasonable ranges of all arguments can be found in defaults_analyze. For high-precision work, first extract and manually correct pitch contours with pitch_app, PRAAT, or whatever, and then run analyze(pitchManual = ...) with these manual contours.


  samplingRate = NULL,
  scale = NULL,
  from = NULL,
  to = NULL,
  dynamicRange = 80,
  silence = 0.04,
  windowLength = 50,
  step = 25,
  overlap = 50,
  specType = c("spectrum", "reassign", "spectralDerivative")[1],
  wn = "gaussian",
  zp = 0,
  cutFreq = NULL,
  nFormants = 3,
  formants = list(),
  loudness = list(SPL_measured = 70),
  roughness = list(windowLength = 15, step = 3, amRes = 10),
  novelty = list(input = "melspec", kernelLen = 100),
  pitchMethods = c("dom", "autocor"),
  pitchManual = NULL,
  entropyThres = 0.6,
  pitchFloor = 75,
  pitchCeiling = 3500,
  priorMean = 300,
  priorSD = 6,
  priorAdapt = TRUE,
  nCands = 1,
  minVoicedCands = NULL,
  pitchDom = list(domThres = 0.1, domSmooth = 220),
  pitchAutocor = list(autocorThres = 0.7, autocorSmooth = 7, autocorUpsample = 25,
    autocorBestPeak = 0.975),
  pitchCep = list(cepThres = 0.75, cepZp = 0),
  pitchSpec = list(specThres = 0.05, specPeak = 0.25, specHNRslope = 0.8, specSmooth =
    150, specMerge = 0.1, specSinglePeakCert = 0.4, specRatios = 3),
  pitchHps = list(hpsNum = 5, hpsThres = 0.1, hpsNorm = 2, hpsPenalty = 2),
  pitchZc = list(zcThres = 0.1, zcWin = 5),
  harmHeight = list(harmThres = 3, harmTol = 0.25, harmPerSel = 5),
  subh = list(method = c("cep", "pitchCands", "harm")[1], nSubh = 5, tol = 0.05, nHarm =
    5, harmThres = 12, harmTol = 0.25, amRange = c(10, 200)),
  flux = list(thres = 0.15, smoothWin = 100),
  amRange = c(10, 200),
  fmRange = c(5, 1000/step/2),
  shortestSyl = 20,
  shortestPause = 60,
  interpol = list(win = 75, tol = 0.3, cert = 0.3),
  pathfinding = c("none", "fast", "slow")[2],
  annealPars = list(maxit = 5000, temp = 1000),
  certWeight = 0.5,
  snakeStep = 0,
  snakePlot = FALSE,
  smooth = 1,
  smoothVars = c("pitch", "dom"),
  summaryFun = c("mean", "median", "sd"),
  invalidArgAction = c("adjust", "abort", "ignore")[1],
  reportEvery = NULL,
  cores = 1,
  plot = FALSE,
  osc = "linear",
  showLegend = TRUE,
  savePlots = NULL,
  pitchPlot = list(col = rgb(0, 0, 1, 0.75), lwd = 3, showPrior = TRUE),
  extraContour = NULL,
  ylim = NULL,
  xlab = "Time",
  ylab = NULL,
  main = NULL,
  width = 900,
  height = 500,
  units = "px",
  res = NA,



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


sampling rate of x (only needed if x is a numeric vector)


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 (s)


dynamic range, dB. All values more than one dynamicRange under maximum are treated as zero


(0 to 1 as proportion of max amplitude) frames with RMS amplitude below silence * max_ampl adjusted by scale are not analyzed at all.


length of FFT window, ms


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 between successive FFT frames, %


plot the original FFT ('spectrum'), reassigned spectrogram ('reassigned'), or spectral derivative ('spectralDerivative')


window type accepted by ftwindow, currently gaussian, hanning, hamming, bartlett, rectangular, blackman, flattop


window length after zero padding, points


if specified, spectral descriptives (peakFreq, specCentroid, specSlope, and quartiles) are calculated only between cutFreq[1] and cutFreq[2], Hz. If a single number is given, analyzes frequencies from 0 to cutFreq. For ex., when analyzing recordings with varying sampling rates, set to half the lowest sampling rate to make the spectra more comparable. Note that "entropyThres" applies only to this frequency range, which also affects which frames will not be analyzed with pitchAutocor.


the number of formants to extract per STFT frame (0 = no formant analysis, NULL = as many as possible)


a list of arguments passed to findformants - an external function called to perform LPC analysis


a list of parameters passed to getLoudness for measuring subjective loudness, namely SPL_measured, Pref, spreadSpectrum. NULL = skip loudness analysis


a list of parameters passed to modulationSpectrum for measuring roughness. NULL = skip roughness analysis


a list of parameters passed to ssm for measuring spectral novelty. NULL = skip novelty analysis


methods of pitch estimation to consider for determining pitch contour: 'autocor' = autocorrelation (~PRAAT), 'cep' = cepstral, 'spec' = spectral (~BaNa), 'dom' = lowest dominant frequency band, 'hps' = harmonic product spectrum, NULL = no pitch analysis


manually corrected pitch contour. For a single sound, provide a numeric vector of any length. For multiple sounds, provide a dataframe with columns "file" and "pitch" (or path to a csv file) as returned by pitch_app, ideally with the same windowLength and step as in current call to analyze. A named list with pitch vectors per file is also OK (eg as returned by pitch_app)


pitch tracking is only performed for frames with Weiner entropy below entropyThres, but other spectral descriptives are still calculated (NULL = analyze everything)

pitchFloor, pitchCeiling

absolute bounds for pitch candidates (Hz)

priorMean, priorSD

specifies the mean (Hz) and standard deviation (semitones) of gamma distribution describing our prior knowledge about the most likely pitch values for this file. For ex., priorMean = 300, priorSD = 6 gives a prior with mean = 300 Hz and SD = 6 semitones (half an octave)


adaptive second-pass prior: if TRUE, optimal pitch contours are estimated first with a prior determined by priorMean,priorSD, and then with a new prior adjusted according to this first-pass pitch contour


maximum number of pitch candidates per method, normally 1...4 (except for dom, which returns at most one candidate per frame)


minimum number of pitch candidates that have to be defined to consider a frame voiced (if NULL, defaults to 2 if dom is among other candidates and 1 otherwise)


a list of control parameters for pitch tracking using the lowest dominant frequency band or "dom" method; see details and ?soundgen:::getDom


a list of control parameters for pitch tracking using the autocorrelation or "autocor" method; see details and ?soundgen:::getPitchAutocor


a list of control parameters for pitch tracking using the cepstrum or "cep" method; see details and ?soundgen:::getPitchCep


a list of control parameters for pitch tracking using the BaNa or "spec" method; see details and ?soundgen:::getPitchSpec


a list of control parameters for pitch tracking using the harmonic product spectrum or "hps" method; see details and ?soundgen:::getPitchHps


a list of control parameters for pitch tracking based on zero crossings in bandpass-filtered audio or "zc" method; see getPitchZc


a list of control parameters for estimating how high harmonics reach in the spectrum; see details and ?soundgen:::harmHeight


a list of control parameters for estimating the strength of subharmonics per frame - that is, spectral energy at integer ratios of f0: see ?soundgen:::subhToHarm


a list of control parameters for calculating feature-based flux (not spectral flux) passed to getFeatureFlux


target range of frequencies for amplitude modulation, Hz: a vector of length 2 (affects both amMsFreq and amEnvFreq)


target range of frequencies for analyzing frequency modulation, Hz (fmFreq): a vector of length 2


the smallest length of a voiced segment (ms) that constitutes a voiced syllable (shorter segments will be replaced by NA, as if unvoiced)


the smallest gap between voiced syllables (ms): large value = interpolate and merge, small value = treat as separate syllables separated by an unvoiced gap


a list of parameters (currently win, tol, cert) passed to soundgen:::pathfinder for interpolating missing pitch candidates (NULL = no interpolation)


method of finding the optimal path through pitch candidates: 'none' = best candidate per frame, 'fast' = simple heuristic, 'slow' = annealing. See soundgen:::pathfinder


a list of control parameters for postprocessing of pitch contour with SANN algorithm of optim. This is only relevant if pathfinding = 'slow'


(0 to 1) in pitch postprocessing, specifies how much we prioritize the certainty of pitch candidates vs. pitch jumps / the internal tension of the resulting pitch curve


optimized path through pitch candidates is further processed to minimize the elastic force acting on pitch contour. To disable, set snakeStep = 0


if TRUE, plots the snake

smooth, smoothVars

if smooth is a positive number, outliers of the variables in smoothVars are adjusted with median smoothing. smooth of 1 corresponds to a window of ~100 ms and tolerated deviation of ~4 semitones. To disable, set smooth = 0


functions used to summarize each acoustic characteristic, eg "c('mean', 'sd')"; user-defined functions are fine (see examples); NAs are omitted automatically for mean/median/sd/min/max/range/sum, otherwise take care of NAs yourself


what to do if an argument is invalid or outside the range in defaults_analyze: 'adjust' = reset to default value, 'abort' = stop execution, 'ignore' = throw a warning and continue (may crash)


when processing multiple inputs, report estimated time left every ... iterations (NULL = default, NA = don't report)


number of cores for parallel processing


if TRUE, produces a spectrogram with pitch contour overlaid


"none" = no oscillogram; "linear" = on the original scale; "dB" = in decibels


if TRUE, adds a legend with pitch tracking methods


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


a list of graphical parameters for displaying the final pitch contour. Set to list(type = 'n') to suppress


name of an output variable to overlap on the pitch contour plot, eg 'peakFreq' or 'loudness'; can also be a list with extra graphical parameters, eg extraContour = list(x = 'harmHeight', col = 'red')


frequency range to plot, kHz (defaults to 0 to Nyquist frequency). NB: still in kHz, even if yScale = bark, mel, or ERB

xlab, ylab, main

plotting parameters

width, height, units, res

parameters passed to png if the plot is saved


other graphical parameters passed to spectrogram


Each pitch tracker is controlled by its own list of settings, as follows:

pitchDom (lowest dominant frequency band)
  • domThres (0 to 1) to find the lowest dominant frequency band, we do short-term FFT and take the lowest frequency with amplitude at least domThres

  • domSmooth the width of smoothing interval (Hz) for finding dom

pitchAutocor (autocorrelation)
  • autocorThres voicing threshold (unitless, ~0 to 1)

  • autocorSmooth the width of smoothing interval (in bins) for finding peaks in the autocorrelation function. Defaults to 7 for sampling rate 44100 and smaller odd numbers for lower values of sampling rate

  • autocorUpsample upsamples acf to this resolution (Hz) to improve accuracy in high frequencies

  • autocorBestPeak amplitude of the lowest best candidate relative to the absolute max of the acf

pitchCep (cepstrum)
  • cepThres voicing threshold (unitless, ~0 to 1)

  • cepZp zero-padding of the spectrum used for cepstral pitch detection (final length of spectrum after zero-padding in points, e.g. 2 ^ 13)

pitchSpec (ratio of harmonics - BaNa algorithm)
  • specThres voicing threshold (unitless, ~0 to 1)

  • specPeak,specHNRslope when looking for putative harmonics in the spectrum, the threshold for peak detection is calculated as specPeak * (1 - HNR * specHNRslope)

  • specSmooth the width of window for detecting peaks in the spectrum, Hz

  • specMerge pitch candidates within specMerge semitones are merged with boosted certainty

  • specSinglePeakCert (0 to 1) if F0 is calculated based on a single harmonic ratio (as opposed to several ratios converging on the same candidate), its certainty is taken to be specSinglePeakCert

pitchHps (harmonic product spectrum)
  • hpsNum the number of times to downsample the spectrum

  • hpsThres voicing threshold (unitless, ~0 to 1)

  • hpsNorm the amount of inflation of hps pitch certainty (0 = none)

  • hpsPenalty the amount of penalizing hps candidates in low frequencies (0 = none)

Each of these lists also accepts graphical parameters that affect how pitch candidates are plotted, eg pitchDom = list(domThres = .5, col = 'yellow'). Other arguments that are lists of subroutine-specific settings include:

harmonicHeight (finding how high harmonics reach in the spectrum)
  • harmThres minimum height of spectral peak, dB

  • harmPerSel the number of harmonics per sliding selection

  • harmTol maximum tolerated deviation of peak frequency from multiples of f0, proportion of f0


Returns a list with $detailed frame-by-frame descriptives and a $summary with one row per file, as determined by summaryFun (e.g., mean / median / SD of each acoustic variable across all STFT frames). Output measures include:


total duration, s


duration from the beginning of the first non-silent STFT frame to the end of the last non-silent STFT frame, s (NB: depends strongly on windowLength and silence settings)


time of the middle of each frame (ms)


frequency (Hz) and depth (0 to 1) of amplitude modulation estimated from a smoothed amplitude envelope


frequency and purity of amplitude modulation estimated via modulationSpectrum


root mean square of amplitude per frame, calculated as sqrt(mean(frame ^ 2))


same as ampl, but ignoring silent frames


Cepstral Peak Prominence, dB (a measure of pitch quality, the ratio of the highest peak in the cepstrum to the regression line drawn through it)


lowest dominant frequency band (Hz) (see "Pitch tracking methods / Dominant frequency" in the vignette)


Weiner entropy of the spectrum of the current frame. Close to 0: pure tone or tonal sound with nearly all energy in harmonics; close to 1: white noise


Normalized Shannon entropy of the spectrum of the current frame: 0 = pure tone, 1 = white noise

f1_freq, f1_width, ...

the frequency and bandwidth of the first nFormants formants per STFT frame, as calculated by phonTools::findformants


feature-based flux, the rate of change in acoustic features such as pitch, HNR, etc. (0 = none, 1 = max); "epoch" is an audio segment between two peaks of flux that exceed a threshold of flux = list(thres = ...) (listed in output$detailed only)


frequency of frequency modulation (FM) such as vibrato or jitter, Hz


depth of FM, semitones


purity or dominance of the main FM frequency (fmFreq), 0 to 1


the amount of energy in upper harmonics, namely the ratio of total spectral mass above 1.25 x F0 to the total spectral mass below 1.25 x F0 (dB)


how high harmonics reach in the spectrum, based on the best guess at pitch (or the manually provided pitch values)


harmonics-to-noise ratio (dB), a measure of harmonicity returned by soundgen:::getPitchAutocor (see "Pitch tracking methods / Autocorrelation"). If HNR = 0 dB, there is as much energy in harmonics as in noise


subjective loudness, in sone, corresponding to the chosen SPL_measured - see getLoudness


spectral novelty - a measure of how variable the spectrum is on a particular time scale, as estimated by ssm


the frequency with maximum spectral power (Hz)


post-processed pitch contour based on all F0 estimates

quartile25, quartile50, quartile75

the 25th, 50th, and 75th quantiles of the spectrum of voiced frames (Hz)


the amount of amplitude modulation, see modulationSpectrum


the center of gravity of the frame’s spectrum, first spectral moment (Hz)


the slope of linear regression fit to the spectrum below cutFreq (dB/kHz)


estimated depth of subharmonics per frame: 0 = none, 1 = as strong as f0. NB: this depends critically on accurate pitch tracking


the ratio of f0 to subharmonics frequency with strength subDep: 2 = period doubling, 3 = f0 / 3, etc.


is the current STFT frame voiced? TRUE / FALSE

See Also

pitch_app getLoudness segment getRMS


sound = soundgen(sylLen = 300, pitch = c(500, 400, 600),
  noise = list(time = c(0, 300), value = c(-40, 0)),
  temperature = 0.001,
  addSilence = 50)  # NB: always have some silence before and after!!!
# playme(sound, 16000)
a = analyze(sound, samplingRate = 16000, plot = TRUE)
str(a$detailed)  # frame-by-frame
a$summary        # summary per sound

## Not run: 
# For maximum processing speed (just basic spectral descriptives):
a = analyze(sound, samplingRate = 16000,
  plot = FALSE,         # no plotting
  pitchMethods = NULL,  # no pitch tracking
  loudness = NULL,      # no loudness analysis
  novelty = NULL,       # no novelty analysis
  roughness = NULL,     # no roughness analysis
  nFormants = 0         # no formant analysis

# Take a sound hard to analyze b/c of subharmonics and jitter
sound2 = soundgen(sylLen = 900, pitch = list(
  time = c(0, .3, .8, 1), value = c(300, 900, 400, 2300)),
  noise = list(time = c(0, 900), value = c(-40, -20)),
  subDep = 10, jitterDep = 0.5,
  temperature = 0.001, samplingRate = 44100, pitchSamplingRate = 44100)
# playme(sound2, 44100)
a2 = analyze(sound2, samplingRate = 44100, priorSD = 24,
             plot = TRUE, ylim = c(0, 5))

# Compare the available pitch trackers
analyze(sound2, 44100,
  pitchMethods = c('dom', 'autocor', 'spec', 'cep', 'hps', 'zc'),
  # don't use priors to see weird pitch candidates better
  priorMean = NA, priorAdapt = FALSE,
  plot = TRUE, yScale = 'bark')

# Fancy plotting options:
a = analyze(sound2, samplingRate = 44100, plot = TRUE,
  xlab = 'Time, ms', colorTheme = 'seewave',
  contrast = .5, ylim = c(0, 4), main = 'My plot',
  pitchMethods = c('dom', 'autocor', 'spec', 'hps', 'cep'),
  priorMean = NA,  # no prior info at all
  pitchDom = list(col = 'red', domThres = .25),
  pitchPlot = list(col = 'black', pch = 9, lty = 3, lwd = 3),
  extraContour = list(x = 'peakFreq', type = 'b', pch = 4, col = 'brown'),
  osc = 'dB', heights = c(2, 1))

# Analyze an entire folder in one go, saving spectrograms with pitch contours
# plus an html file for easy access
s2 = analyze('~/Downloads/temp',
  savePlots = '',  # save in the same folder as audio
  showLegend = TRUE, yScale = 'bark',
  width = 20, height = 12,
  units = 'cm', res = 300, ylim = c(0, 5))
s2$summary[, 1:5]

# Different options for summarizing the output
a = analyze(sound1, 44100,
            summaryFun = c('mean', 'range'))
a$summary  # one row per sound
# ...with custom summaryFun, eg time of peak relative to duration (0 to 1)
timePeak = function(x) which.max(x) / length(x)  # without omitting NAs
timeTrough = function(x) which.min(x) / length(x)
a = analyze(sound2, samplingRate = 16000,
            summaryFun = c('mean', 'timePeak', 'timeTrough'))

# Analyze a selection rather than the whole sound
a = analyze(sound, samplingRate = 16000, from = .1, to = .3, plot = TRUE)

# Use only a range of frequencies when calculating spectral descriptives
# (ignore everything below 100 Hz and above 8000 Hz as irrelevant noise)
a = analyze(sound, samplingRate = 16000, cutFreq = c(100, 8000))

## Amplitude and loudness: analyze() should give the same results as
# dedicated functions getRMS() / getLoudness()
# Create 1 kHz tone
samplingRate = 16000; dur_ms = 50
sound3 = sin(2*pi*1000/samplingRate*(1:(dur_ms/1000*samplingRate)))
a1 = analyze(sound3, samplingRate = samplingRate, scale = 1,
             windowLength = 25, overlap = 50,
             loudness = list(SPL_measured = 40),
             pitchMethods = NULL, plot = FALSE)
a1$detailed$loudness  # loudness per STFT frame (1 sone by definition)
getLoudness(sound3, samplingRate = samplingRate, windowLength = 25,
            overlap = 50, SPL_measured = 40, scale = 1)$loudness
a1$detailed$ampl  # RMS amplitude per STFT frame
getRMS(sound3, samplingRate = samplingRate, windowLength = 25,
       overlap = 50, scale = 1)$detailed
# or even simply: sqrt(mean(sound3 ^ 2))

# The same sound as above, but with half the amplitude
a_half = analyze(sound3 / 2, samplingRate = samplingRate, scale = 1,
                 windowLength = 25, overlap = 50,
                 loudness = list(SPL_measured = 40),
                 pitchMethods = NULL, plot = FALSE)
a1$detailed$ampl / a_half$detailed$ampl  # rms amplitude halved
a1$detailed$loudness/ a_half$detailed$loudness
# loudness is not a linear function of amplitude

# Analyzing ultrasounds (slow but possible, just adjust pitchCeiling)
s = soundgen(sylLen = 100, addSilence = 10,
  pitch = c(25000, 35000, 30000),
  formants = NA, rolloff = -12, rolloffKHz = 0,
  pitchSamplingRate = 350000, samplingRate = 350000, windowLength = 5,
  pitchCeiling = 45000, invalidArgAction = 'ignore')
# s is a bat-like ultrasound inaudible to humans
a = analyze(s, 350000, plot = TRUE,
            pitchCeiling = 45000, priorMean = NA,
            windowLength = 2, overlap = 0,
            nFormants = 0, loudness = NULL)
# NB: ignore formants and loudness estimates for such non-human sounds

# download 260 sounds from Anikin & Persson (2017)
# unzip them into a folder, say '~/Downloads/temp'
myfolder = '~/Downloads/temp'  # 260 .wav files live here
s = analyze(myfolder)  # ~ 10-20 minutes!
# s = write.csv(s, paste0(myfolder, '/temp.csv'))  # save a backup

# Check accuracy: import manually verified pitch values (our "key")
# pitchManual   # "ground truth" of mean pitch per sound
# pitchContour  # "ground truth" of complete pitch contours per sound
files_manual = paste0(names(pitchManual), '.wav')
idx = match(s$file, files_manual)  # in case the order is wrong
s$key = pitchManual[idx]

# Compare manually verified mean pitch with the output of analyze:
cor(s$key, s$summary$pitch_median, use = 'pairwise.complete.obs')
plot(s$key, s$summary$pitch_median, log = 'xy')
abline(a=0, b=1, col='red')

# Re-running analyze with manually corrected contours gives correct
pitch-related descriptives like amplVoiced and harmonics (NB: you get it "for
free" when running pitch_app)
s1 = analyze(myfolder, pitchManual = pitchContour)
plot(s$summary$harmonics_median, s1$summary$harmonics_median)
abline(a=0, b=1, col='red')

## End(Not run)

soundgen documentation built on Sept. 29, 2023, 5:09 p.m.