createCea708PacketFromBytes = (bytes, pts) => {
    const cea708Bytes = bytes.map((code, i) => {
      return {
        pts,
        type: shaka.cea.DtvccPacketBuilder.DTVCC_PACKET_DATA,
        value: code,
        order: i,
      };
    });
    return new shaka.cea.DtvccPacket(cea708Bytes);
  }
Takes in a array of bytes and a presentation timestamp (in seconds),
and converts it into a CEA-708 DTVCC Packet.
@param {!Array<number>} bytes
@param {number} pts
@return {!shaka.cea.DtvccPacket}