PitchTier

Praat PitchTier object: a sequence of time-value points describing a pitch contour.

Arguments

tmin

Start time in seconds, for creating an empty PitchTier.

tmax

End time in seconds, for creating an empty PitchTier.

.xptr

Not for direct use. External pointer to the underlying C++ PitchTier object; set internally when a method returns a new PitchTier.

Value

A PitchTier object with methods for pitch-contour manipulation via time-value points.

Details

PitchTiers are used together with Manipulation objects to modify the pitch contour of sounds. Unlike Pitch objects, which hold sampled data, PitchTiers hold discrete time-value pairs that can be edited directly.

Usage

PitchTier$new(path)          # load from file
PitchTier(tmin, tmax)        # create an empty PitchTier
pitch$down_to_pitch_tier()   # extract from a Pitch object

Query methods

• get_number_of_points() - number of pitch points

• get_value_at_time(time) - interpolated F0 at a time

• get_value_at_index(index) - F0 of a specific point

• get_time_from_index(index) - time of a specific point

• get_minimum(), get_maximum() - F0 range

• get_mean(tmin, tmax) - mean F0 (interpolated curve)

• get_standard_deviation(tmin, tmax) - standard deviation

• get_area(tmin, tmax) - area under the curve

Modification

• add_point(time, value) - add a pitch point (Hz)

• remove_point(index) - remove a point by index

• remove_points_between(tmin, tmax) - remove points in a time range

• multiply_frequencies(factor) - scale all frequencies

• multiply_frequencies_in_range(tmin, tmax, factor) - scale in a range

• shift_frequencies(shift, unit) - add to all frequencies

• shift_frequencies_in_range(tmin, tmax, shift, unit) - shift in a range

• stylize(frequency_resolution, use_semitones) - simplify the contour

• interpolate_quadratically(points_per_parabola, logarithmically) - smooth the contour

Conversion

• to_sound_pulse_train(sample_rate) - synthesize a pulse train

• to_sound_phonation(sample_rate) - synthesize phonation

• to_sound_sine(sample_rate) - synthesize a sine wave

• down_to_point_process() - extract time points

• to_pitch(time_step, pitch_floor, pitch_ceiling) - convert to a Pitch object

Export

• as_data_frame() - convert to a data.table

• as_matrix() - convert to a matrix

• save(path) - write to file

Examples

# Create empty PitchTier and add points
pt <- PitchTier(0, 1)
pt$add_point(0.1, 120)
pt$add_point(0.5, 150)
pt$add_point(0.9, 100)

# Create from Pitch
sound <- Sound$create_tone(frequency = 150, duration = 0.5)
pitch <- sound$to_pitch()
pitch_tier <- pitch$down_to_pitch_tier()

# Modify pitch
pitch_tier$multiply_frequencies(1.5)  # Raise pitch 50%

# Query
f0_at_mid <- pitch_tier$get_value_at_time(0.25)
n_points <- pitch_tier$get_number_of_points()
f0_min <- pitch_tier$get_minimum()
f0_max <- pitch_tier$get_maximum()

# Synthesize
synth <- pitch_tier$to_sound_sine(16000)

# Export
df <- pitch_tier$as_data_frame()