static BWImageAndRange audioFileToBWImageAndRange(File audioFile) {
  BWImage image = wavToFrequencyImage(audioFile);
  L<IntRange> parts = markerIntRangesForWAV(audioFile, image);
  BWImageAndRange out = nu(BWImageAndRange, +image);
  if (nempty(parts)) {
    out.start = first(parts).start;
    out.end = first(parts).end;
  }
  ret out;
}