Internal soundgen function.
findSyllables(ampl, step, windowLength, threshold, shortestSyl, shortestPause)time difference between two points in the envelope (ms)
length of FFT window, ms
all continuous segments above this value are considered to be syllables
minimum acceptable length of syllables, ms
minimum acceptable break between syllables, ms (syllables separated by shorter pauses are merged)
downsampled amplitude envelope: dataframe with columns "time" and "value"
Returns a dataframe with timing of syllables.
Called by segment.