getAudioData() {
    if (this.audioData_.length && !this.audioPes_.length) {
      for (const audioDataArray of this.audioData_) {
        const audioData = shaka.util.Uint8ArrayUtils.concat(...audioDataArray);
        const pes = this.parsePES_(audioData);
        let previousPes = this.audioPes_.length ?
            this.audioPes_[this.audioPes_.length - 1] : null;
        if (pes && pes.pts != null && pes.dts != null && (!previousPes ||
            (previousPes.pts != pes.pts && previousPes.dts != pes.dts))) {
          this.audioPes_.push(pes);
        } else if (this.audioPes_.length) {
          const data = pes ? pes.data : audioData;
          if (!data) {
            continue;
          }
          previousPes = this.audioPes_.pop();
          previousPes.data =
              shaka.util.Uint8ArrayUtils.concat(previousPes.data, data);
          this.audioPes_.push(previousPes);
        }
      }
    }
    return this.audioPes_;
  }
Return the audio data

@return {!Array<shaka.extern.MPEG_PES>}
@export