getAudioTracks() {
    if (this.manifest_ && !this.isRemotePlayback()) {
      const variants = this.getVariantTracks();
      if (!variants.length) {
        return [];
      }
      const active = variants.find((t) => t.active);
      if (!active) {
        return [];
      }
      let filteredTracks = variants;
      if (this.loadMode_ == shaka.Player.LoadMode.MEDIA_SOURCE &&
          !this.isRemotePlayback()) {
        // Filter by current videoId and has audio.
        filteredTracks = variants.filter((t) => {
          return t.originalVideoId === active.originalVideoId && t.audioCodec;
        });
      }
      if (!filteredTracks.length) {
        return [];
      }

      /** @type {!Map<string, shaka.extern.AudioTrack>} */
      const audioTracksMap = new Map();
      for (const track of filteredTracks) {
        let id = track.originalAudioId;
        if (!id && track.audioId != null) {
          id = String(track.audioId);
        }
        if (!id) {
          continue;
        }
        /** @type {shaka.extern.AudioTrack} */
        const audioTrack = {
          active: track.active,
          language: track.language,
          label: track.label,
          mimeType: track.audioMimeType,
          codecs: track.audioCodec,
          primary: track.primary,
          roles: track.audioRoles || [],
          accessibilityPurpose: track.accessibilityPurpose,
          channelsCount: track.channelsCount,
          audioSamplingRate: track.audioSamplingRate,
          spatialAudio: track.spatialAudio,
          originalLanguage: track.originalLanguage,
        };
        audioTracksMap.set(id, audioTrack);
      }
      return Array.from(audioTracksMap.values());
    } else if (this.video_ && this.video_.audioTracks) {
      return Array.from(this.video_.audioTracks).map((audio) =>
        shaka.util.StreamUtils.html5AudioTrackToTrack(audio));
    } else {
      return [];
    }
  }
Return a list of audio tracks compatible with the current video track.

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