Android AVRCP

https://www.cnblogs.com/fuyaozhishang/p/7639675.html

https://gist.github.com/davidalbers/953eb949314fd6607616

https://android.googlesource.com/platform/packages/apps/Bluetooth/+/fb798085afa118749864d1fae0506851a1390b87/src/com/android/bluetooth/avrcp/Avrcp.java

https://stackoverrun.com/cn/q/5804224

https://stackoverrun.com/cn/q/3579014

https://developer.android.com/reference/android/media/RemoteControlClient.MetadataEditor

https://www.youtube.com/watch?v=EC5-cEbr520&feature=youtu.be&t=25m18s