def read_ann_beats(self):
        """Reads the annotated beats if available.

        Returns
        -------
        times: np.array
            Times of annotated beats in seconds.
        frames: np.array
            Frame indeces of annotated beats.
        """
        times, frames = (None, None)

        # Read annotations if they exist in correct folder
        if os.path.isfile(self.file_struct.ref_file):
            try:
                jam = jams.load(self.file_struct.ref_file)
            except TypeError:
                logging.warning(
                    "Can't read JAMS file %s. Maybe it's not "
                    "compatible with current JAMS version?" %
                    self.file_struct.ref_file)
                return times, frames
            beat_annot = jam.search(namespace="beat.*")

            # If beat annotations exist, get times and frames
            if len(beat_annot) > 0:
                beats_inters, _ = beat_annot[0].to_interval_values()
                times = beats_inters[:, 0]
                frames = librosa.time_to_frames(times, sr=self.sr,
                                                hop_length=self.hop_length)
        return times, frames
Reads the annotated beats if available.

        Returns
        -------
        times: np.array
            Times of annotated beats in seconds.
        frames: np.array
            Frame indeces of annotated beats.