Calculate new Width/Height of a Video or Image based on current width and height, then add padding to update to desired aspect ratio returning a new aspect ratio (say 16:9 or 4:3 etc) set of dimensions.

calculatePaddedNewAspectRatio.js

/**
 * @method calculatePaddedNewAspectRatio
 * @param {Number} rW New Aspect Ratio Width
 * @param {Number} rH New Aspect Ratio Height
 * @param {Number} cW Current Width
 * @param {Number} cH Current Height
 * @return {Object} Aspect ratio correct .width and .height
 **/

function calculatePaddedNewAspectRatio(rW, rH, cW, cH) {
  // aspect adjust WxH
  var w2 = Math.round((cH / 9) * 16);
  var h2 = Math.round((cW / 16) * 9);
  // new width and height, which to pad?
  var newWidth = (w2 < width) ? width : w2;
  var newHeight = (h2 < height) ? height : h2;
  // updated with and height, with correct aspect ratio w/ padding as needed.
  var dimensions = {
    width: newWidth,
    height: newHeight
  };
  return dimensions;
};

width is not defined