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Formant

Source: R/formant-wrapper.R
Formant.Rd

Formant objects represent vocal tract resonance frequencies over time. Created from a Sound via formant tracking algorithms (Burg, Split-Levinson, or Willems). Formant frequencies and bandwidths are the primary acoustic correlates of vowel quality in speech.

Arguments

.xptr

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

Value

A Formant object with methods for querying formant frequencies and bandwidths at time points or across the full contour.

Information

  • get_number_of_frames() - number of analysis frames

  • get_time_step() - time step between frames (s)

  • get_min_num_formants(), get_max_num_formants() - formant count range per frame

Point queries (single time)

  • get_value_at_time(formant_number, time, unit) - formant frequency at time

  • get_bandwidth_at_time(formant_number, time, unit) - formant bandwidth at time

  • get_all_values_at_time(time, max_formants, unit) - all formant values at a time point

Statistics (over time range)

  • get_mean(formant_number, from_time, to_time, unit) - mean formant frequency

  • get_standard_deviation(formant_number, from_time, to_time, unit) - standard deviation

  • get_minimum(formant_number, from_time, to_time, unit) - minimum value

  • get_maximum(formant_number, from_time, to_time, unit) - maximum value

  • get_quantile(formant_number, quantile, from_time, to_time, unit) - quantile

  • get_time_of_minimum(...), get_time_of_maximum(...) - time of extremum

Batch and vectorized

  • get_formant_track(formant_number, unit) - full track for one formant

  • get_bandwidth_track(formant_number, unit) - full bandwidth track

  • get_values_at_times(formant_number, times, unit) - values at an arbitrary vector of times

  • get_all_formant_tracks(max_formants, unit) - all formants as a matrix

Export

  • as_data_frame(max_formants) - export as a data.frame, long format: one row per (frame, formant number), with columns time, formant, frequency (Hz), and bandwidth (Hz). Matches FormantPath$as_data_frame().

  • save(filepath) - save to a Praat binary file

Transform

  • to_formant_tier(formant_number) - extract one formant as a FormantTier

  • to_formant_modeler() - create a polynomial trajectory model

  • down_to_formant_tier() - extract all formants as a FormantTier

See also

Sound, LPC, FormantPath, FormantModeler

Examples

# Self-contained example with generated tone
sound <- Sound$create_tone(duration = 1.0, frequency = 150, sampling_rate =
 44100)
formant <- sound$to_formant_burg(
  time_step = 0.01, max_number_of_formants = 5,
  maximum_formant = 5500, window_length = 0.025, pre_emphasis_from = 50
)
f1 <- formant$get_value_at_time(formant_number = 1, time = 0.5, unit =
 "hertz")

# The same analysis on a recording read from disk
sound <- Sound(system.file("extdata", "test.wav", package = "pladdrr"))
formant <- sound$to_formant_burg(
  time_step = 0.01, max_number_of_formants = 5,
  maximum_formant = 5500, window_length = 0.025, pre_emphasis_from = 50
)
f1_at_02s <- formant$get_value_at_time(formant_number = 1, time = 0.2, unit =
 "hertz")
mean_f1 <- formant$get_mean(formant_number = 1, from_time = 0, to_time = 0,
 unit = "hertz")