Android4.4
输入输出设备
输入输出设备，定义在frameworks/base/media/java/android/media/AudioSystem.java和system/core/include/system/audio.h
// output devices DEVICE_OUT_EARPIECE = 0x1, //听筒 DEVICE_OUT_SPEAKER = 0x2, //扬声器 DEVICE_OUT_WIRED_HEADSET = 0x4, //带话筒的耳机 DEVICE_OUT_WIRED_HEADPHONE = 0x8, //不带话筒的耳机 DEVICE_OUT_BLUETOOTH_SCO = 0x10, //蓝牙.面向连接（SCO）方式：主要用于话音传输 DEVICE_OUT_BLUETOOTH_SCO_HEADSET = 0x20, //蓝牙耳机,带话筒 DEVICE_OUT_BLUETOOTH_SCO_CARKIT = 0x40, //蓝牙车载设备 DEVICE_OUT_BLUETOOTH_A2DP = 0x80, //蓝牙立体声 DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES = 0x100, //蓝牙立体声音耳机 DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER = 0x200, DEVICE_OUT_AUX_DIGITAL = 0x400, DEVICE_OUT_ANLG_DOCK_HEADSET = 0x800, DEVICE_OUT_DGTL_DOCK_HEADSET = 0x1000, DEVICE_OUT_FM_HEADPHONE = 0x800, DEVICE_OUT_FM_SPEAKER = 0x1000, DEVICE_OUT_SPEAKER_SSPA2 = 0x2000, DEVICE_OUT_HDMI = 0x4000, DEVICE_OUT_FM_TRANSMITTER = 0x8000, DEVICE_OUT_DEFAULT = 0x8000, // input devices DEVICE_IN_COMMUNICATION = 0x10000, DEVICE_IN_AMBIENT = 0x20000, DEVICE_IN_BUILTIN_MIC = 0x40000, DEVICE_IN_BLUETOOTH_SCO_HEADSET = 0x80000, DEVICE_IN_WIRED_HEADSET = 0x100000, DEVICE_IN_AUX_DIGITAL = 0x200000, DEVICE_IN_VOICE_CALL = 0x400000, DEVICE_IN_BACK_MIC = 0x800000, DEVICE_IN_VT_MIC = 0x1000000, DEVICE_IN_FMRADIO = 0x2000000, DEVICE_IN_DEFAULT = 0x80000000,
