https://blog.wongcw.com/2018/10/12/android%e5%81%b7%e6%8b%8d%e7%a5%9e%e5%99%a8appbackground-video-recorder%e4%bd%a0%e5%b7%b2%e4%b8%8a%e9%8f%a1%e4%ba%86/