https://blog.wongcw.com/2018/10/12/musictools-v2-2-0-%e5%85%8d%e8%b4%b9%e7%9a%84%e6%97%a0%e6%8d%9f%e9%9f%b3%e4%b9%90%e4%b8%8b%e8%bd%bd%e5%b7%a5%e5%85%b7/