twopass

This plugin implements De Looze and Hirst’s two-pass utterance-specific pitch threshold estimation algorithm. From the researcher’s website:

In order to avoid possible pitch tracking errors, pitch floor and pitch ceiling are set [to q25 * 0.75 and q75 * 1.5 (where q stands for “percentile”), which] have been shown¹²³ to give a better estimation of pitch extrema, i.e. to exclude more octave errors or microprosodic effects at the extreme of the f0 distribution, than setting pitch floor and ceiling parameters to the default values [in Praat] or to default values depending on the gender of the speaker.

The scripts and procedures provided by this plugin are written so that their main intended objective is the creation of Pitch objects with the estimated pitch thresholds. In writing them, scripts provided by the researchers in their website and in the Praat user’s list were taken into consideration.

Scripts

To Pitch (two-pass): floor, ceiling

This script takes a selection of Sound objects, and applies the algorithm described above to each in turn to generate a corresponding Pitch object. The resulting objects are selected at the end.

The parameters passed to the script are the floor and ceiling factors that will be multiplied with the first and third quartiles respectively to estimate the pitch thresholds. A floor factor of 0.75 and a ceiling factor of 1.5 are recommended by the researchers in most cases, but they warn that for “expressive speech”, a ceiling factor of up to 2.5 might give better results.

Passing zeroes instead of these values uses the recommended default values instead.

Batch to Pitch (two-pass): floor, ceiling, input$, output$

Similar to To Pitch (two-pass)…, this script takes floor and ceiling factors, and an input and an output path. Designed for batch processing, this script processes all the sound files in the input$ directory and saves the resulting Pitch objects in the output$ directory.

Passing zeroes as the factors uses the recommended default values.

Procedures

pitchTwoPass: floor, ceiling

sound = selected("Sound")
@pitchTwoPass: 0, 0
assert numberOfSelected("Pitch") == 1

This procedure has the same effect as the To Pitch (two-pass)… script described above, and works in the same way. In fact, it is used internally by all other scripts.

It takes a selected Sound object and generates a Pitch object, which will be selected after completion. For ease, the ID of that object is also stored in the .id variable.