Raises or lowers pitch with or without also shifting the formants (resonance
frequencies) and performing a time-stretch. The three operations (pitch
shift, formant shift, and time stretch) are independent and can be performed
in any combination, statically or dynamically. shiftPitch can also be
used to shift formants without changing pitch or duration, but the dedicated
shiftFormants is faster for that task.
shiftPitch(
x,
multPitch = 1,
multFormants = multPitch,
timeStretch = 1,
samplingRate = NULL,
freqWindow = NULL,
dynamicRange = 80,
windowLength = 40,
step = 2,
overlap = NULL,
wn = "gaussian",
interpol = c("approx", "spline")[1],
propagation = c("time", "adaptive")[1],
preserveEnv = NULL,
transplantEnv_pars = list(windowLength = 10),
normalize = TRUE,
play = FALSE,
saveAudio = NULL,
reportEvery = NULL
)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
1 = no change, >1 = raise pitch (eg 1.1 = 10% up, 2 = one
octave up), <1 = lower pitch. Anchor format accepted for multPitch /
multFormant / timeStretch (see soundgen)
1 = no change, >1 = raise formants (eg 1.1 = 10% up, 2 = one octave up), <1 = lower formants
1 = no change, >1 = longer, <1 = shorter
sampling rate of x (only needed if x is a
numeric vector)
the width of spectral smoothing window, Hz. Defaults to
detected f0 prior to pitch shifting - see shiftFormants for
discussion and examples
dynamic range, dB. All values more than one dynamicRange under maximum are treated as zero
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, %
window type accepted by ftwindow, currently
gaussian, hanning, hamming, bartlett, rectangular, blackman, flattop
the method for interpolating scaled spectra and anchors
the method for propagating phase: "time" = horizontal propagation (default), "adaptive" = an experimental implementation of "vocoder done right" (Prusa & Holighaus 2017)
if TRUE, transplants the amplitude envelope from the
original to the modified sound with transplantEnv. Defaults
to TRUE if no time stretching is performed and FALSE otherwise
a list of parameters passed on to
transplantEnv if preserveEnv = TRUE
if TRUE, scales input prior to FFT
full path to the folder in which to save audio files (one per detected syllable)
when processing multiple inputs, report estimated time left every ... iterations (NULL = default, NA = don't report)
Algorithm: phase vocoder. Pitch shifting is accomplished by performing a time
stretch (at present, with horizontal or adaptive phase propagation) followed
by resampling. This shifts both pitch and formants; to preserve the original
formant frequencies or modify them independently of pitch, a variant of
link{transplantFormants} is performed to "transplant" the original or
scaled formants onto the time-stretched new sound.
# NOT RUN {
s = soundgen(sylLen = 200, ampl = c(0,-10),
pitch = c(250, 350), rolloff = c(-9, -15),
noise = -40,
formants = 'aii', addSilence = 50)
# playme(s)
s1 = shiftPitch(s, samplingRate = 16000, freqWindow = 400,
multPitch = 1.25, multFormants = .8)
# playme(s1)
# }
# NOT RUN {
## Dynamic manipulations
# Add a chevron-shaped pitch contour
s2 = shiftPitch(s, samplingRate = 16000, multPitch = c(1.1, 1.3, .8))
playme(s2)
# Time-stretch only the middle
s3 = shiftPitch(s, samplingRate = 16000, timeStretch = list(
time = c(0, .25, .31, .5, .55, 1),
value = c(1, 1, 3, 3, 1, 1))
)
playme(s3)
## Various combinations of 3 manipulations
data(sheep, package = 'seewave') # import a recording from seewave
playme(sheep)
spectrogram(sheep)
# Raise pitch and formants by 3 semitones, shorten by half
sheep1 = shiftPitch(sheep, multPitch = 2 ^ (3 / 12), timeStretch = 0.5)
playme(sheep1, sheep@samp.rate)
spectrogram(sheep1, sheep@samp.rate)
# Just shorten
shiftPitch(sheep, multPitch = 1, timeStretch = 0.25, play = TRUE)
# Raise pitch preserving formants
sheep2 = shiftPitch(sheep, multPitch = 1.2, multFormants = 1, freqWindow = 150)
playme(sheep2, sheep@samp.rate)
spectrogram(sheep2, sheep@samp.rate)
# }
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