getAACCodec_(qualityLevel, fourCCValue, codecPrivateData) {
    let objectType = 0;

    // Chrome problem, in implicit AAC HE definition, so when AACH is detected
    // in FourCC set objectType to 5 => strange, it should be 2
    if (fourCCValue === 'AACH') {
      objectType = 0x05;
    }
    if (!codecPrivateData) {
      // AAC Main Low Complexity => object Type = 2
      objectType = 0x02;
      if (fourCCValue === 'AACH') {
        // High Efficiency AAC Profile = object Type = 5 SBR
        objectType = 0x05;
      }
    } else if (objectType === 0) {
      objectType = (parseInt(codecPrivateData.substr(0, 2), 16) & 0xF8) >> 3;
    }

    return 'mp4a.40.' + objectType;
  }
@param {!shaka.extern.xml.Node} qualityLevel
@param {string} fourCCValue
@param {?string} codecPrivateData
@return {string}
@private