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Estimate band aperiodicity using the D4C algorithm (WORLD vocoder)

trk_d4c.Rd

Computes per-frame, per-band aperiodicity using the D4C (Death, Destruction, Diversion and Disgrace) estimator from the WORLD vocoder via SPTK. Aperiodicity quantifies noise-to-harmonic energy ratio across frequency bands and is the primary input to WORLD's noise excitation model. Use alongside trk_pitch_rapt() or trk_pitch_swipe() for full WORLD vocoder analysis/resynthesis.

Usage

trk_d4c(listOfFiles, beginTime = 0, endTime = 0, windowShift = 5, minF = 60, maxF = 400, voicing_threshold = 0.1, threshold = 0.85, toFile = TRUE, explicitExt = "ap", 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.

windowShift

Numeric. Frame shift in milliseconds; sets output frame rate (1000 / windowShift Hz). Default 5.0 ms.

minF

Numeric. Minimum F0 in Hz used for the internal pitch estimator. Default 60.0 Hz.

maxF

Numeric. Maximum F0 in Hz used for the internal pitch estimator. Default 400.0 Hz.

voicing_threshold

Numeric. Voicing threshold for the internal F0 detector (0–1; higher = more conservative). Default 0.85.

threshold

Numeric. D4C aperiodicity clipping threshold (0–1). Default 0.85.

toFile

Logical. If TRUE, write SSFF output files and return the count written invisibly. If FALSE, return an AsspDataObj. Default TRUE.

explicitExt

Character. Output file extension. Default "ap".

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 track:

aperiodicity

REAL32, band aperiodicity, 0–1 (0 = fully periodic, 1 = fully aperiodic), n_frames × n_bands where n_bands = floor(fs/2 / 3000) + 1.

Frame rate: 1000 / windowShift Hz (default 200 Hz). If toFile = TRUE: integer count of files written, returned invisibly.

Examples

if (FALSE) { # \dontrun{
# Estimate aperiodicity
trk_d4c("recording.wav")

# Process with custom parameters
trk_d4c("speech.wav", minF = 80, maxF = 350, windowShift = 10)

# Process multiple files
trk_d4c(c("file1.wav", "file2.wav"))
} # }