svoid playAudioFile(File f) {
  if (fileHasExtension(f, "mp3") || isMP3FileByContent(f))
    playMp3(f);
  else if (fileHasExtension(f, "wav") || isRIFFFileByContent(f))
    playWAV(f);
  else
    fail("Can't play audio file: " + f2s(f));
}