Extract formants from wav file in CSV format using Praat and wrassp::forest trackers

wav2formants_csvs.R

# install.pacakges(...) if you do not have the packages below
library(tidyverse)
library(stringr)
library(wrassp)
library(glue)

wav2formants_csvs <- function(in_file) {
    stopifnot(grepl("\\.wav$", in_file))
    stopifnot(file.exists(in_file))
    
    absolute_path   <- normalizePath(in_file)
    
    praat_formants  <- str_replace(absolute_path, "\\.wav$", ".formants.praat.csv")
    forest_formants <- str_replace(absolute_path, "\\.wav$", ".formants.forest.csv")
    script_file     <- tempfile(fileext = ".praat")
    
    # More info, see http://www.fon.hum.uva.nl/praat/manual/Scripting_6_9__Calling_from_the_command_line.html
    # Basically, where is the Praat.exe or Praat.app file on your computer?
    praat_path <- "/Applications/Praat.app/Contents/MacOS/Praat"
    
    write('
        form Test command line calls
        sentence input_file 
        sentence output_file 
        endform
        
        Read from file: input_file$
        To Formant (burg): 0, 5, 5500, 0.025, 50
        Down to Table: "no", "yes", 6, "no", 3, "yes", 3, "yes"
        Save as comma-separated file: output_file$
    ', file = script_file)
    
    praat_call   <- glue('{praat_path} --run {script_file} "{absolute_path}" "{praat_formants}"')
    
    # Execute praat_call as one would in a command line
    system(praat_call)
    
    forest_obj   <- forest(listOfFiles = absolute_path, toFile = FALSE)
    forest_times <- seq(
        from = 0,
        to = nrow(forest_obj$fm) / attr(forest_obj, "sampleRate"),
        length.out = nrow(forest_obj$fm)
    ) %>% signif(digits = 4)

    forest_df  <- cbind(
        time = forest_times,
        forest_obj$fm %>% tibble::as_data_frame() %>% set_names(paste0("f", 1:ncol(.)))
    )

    write_csv(x = forest_df, path = forest_formants)
}