code: function (replayData) {
      var data = this.data;
      var self = this;
      var sceneEl = this.el;
  
      if (this.isReplaying) { return; }
  
      // Wait for camera.
      if (!this.el.camera) {
        this.el.addEventListener('camera-set-active', function waitForCamera () {
          self.startReplaying(replayData);
          self.el.removeEventListener('camera-set-active', waitForCamera);
        });
        return;
      }
  
      this.replayData = replayData;
      this.isReplaying = true;
  
      this.cameraEl.removeAttribute('motion-capture-replayer');
  
      Object.keys(replayData).forEach(function setReplayer (key) {
        var replayingEl;
  
        if (key === 'camera') {
          // Grab camera.
          replayingEl = self.cameraEl;
        } else {
          // Grab other entities.
          replayingEl = sceneEl.querySelector('#' + key);
          if (!replayingEl) {
            error('No element found with ID ' + key + '.');
            return;
          }
        }
  
        log('Setting motion-capture-replayer on ' + key + '.');
        replayingEl.setAttribute('motion-capture-replayer', {loop: data.loop});
        replayingEl.components['motion-capture-replayer'].startReplaying(replayData[key]);
      });
    }
docs: Set player on camera and controllers (marked by ID).
  
  @params {object} replayData - {
  camera: {poses: [], events: []},
  [c1ID]: {poses: [], events: []},
  [c2ID]: {poses: [], events: []}
  }