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Extract glottal flow waveform using Iterative Adaptive Inverse Filtering (IAIF)

trk_covarep_iaif.Rd

Separates the glottal source from the vocal tract contribution using the IAIF algorithm (Alku 1992) . Returns sample-rate glottal flow and its derivative (MFDR), which are used for voice quality analysis and dysphonia assessment. Prefer this over GFM-IAIF when a sample-domain output at the native audio rate is needed.

Usage

trk_covarep_iaif(listOfFiles, beginTime = 0, endTime = 0, order_vt = NULL, order_gl = NULL, leaky_coef = 0.99, hpfilt = TRUE, toFile = TRUE, explicitExt = "glf", outputDirectory = NULL, verbose = TRUE, ...)

Arguments

listOfFiles

Character vector of audio file paths. Any format supported by av is accepted; non-native inputs are transcoded automatically.

...

Additional arguments (currently unused).

order_vt

Integer. Vocal tract LPC order. NULL (default) sets it automatically to 2 * round(fs/2000) + 4 (typically 12–20).

order_gl

Integer. Glottal source LPC order. NULL (default) sets it automatically to 2 * round(fs/4000) (typically 2–4).

leaky_coef

Numeric. Leaky integration coefficient for lip radiation compensation (0 < leaky_coef < 1). Default 0.99.

hpfilt

Logical. Apply high-pass filter before processing. Default TRUE.

toFile

Logical. If TRUE, write SSFF output files and return file paths. If FALSE, return an AsspDataObj. Default TRUE.

explicitExt

Character. Output file extension. Default "glf".

beginTime

Start time for the extracted portion in seconds. Default: NULL (beginning of signal). Note: uses beginTime/endTime (seconds) matching DSP function conventions, unlike read_audio() which uses begin/end.

endTime

The end time of the section of the sound files that should be analysed (in seconds). Use 0 for end of file.

outputDirectory

The directory where the slice file should be stored. If not defiled (NULL), the sparse slice file will placed in the same folder as the media file.

verbose

Logical. Show a progress bar (sequential path) or a progress-aware parallel apply (pbapply/pbmcapply, if installed).

Value

If toFile = FALSE: an AsspDataObj with tracks:

glottal_flow

REAL64, estimated glottal flow waveform, dimensionless, n_samples × 1. Same length as the input audio.

glottal_derivative

REAL64, glottal flow derivative (MFDR proxy), dimensionless, n_samples × 1.

Frame rate equals the audio sample rate. If toFile = TRUE: character vector of output file paths.

Details

Default LPC orders follow the original COVAREP/MATLAB implementation. order_gl = 3 is recommended; departing from this may yield unreliable source estimates.

References

(Alku 1992)

See also

lst_covarep_vq for voice quality parameters, trk_gfmiaif for GFM-IAIF (LP-coefficient output)

Examples

if (FALSE) { # \dontrun{
# Single file - extract glottal flow
glottal <- trk_covarep_iaif("vowel.wav", toFile = FALSE)
plot(glottal$glottal_flow, type = "l", ylab = "Glottal Flow")
plot(glottal$glottal_derivative, type = "l", ylab = "Glottal Derivative")

# Batch processing
files <- c("a.wav", "e.wav", "i.wav")
result <- trk_covarep_iaif(files, toFile = TRUE)

# Custom filter orders
glottal_custom <- trk_covarep_iaif("audio.wav",
                                   order_vt = 16,
                                   order_gl = 3,
                                   toFile = FALSE)
} # }