Android 录屏相关

首先要做的是设置属性REMOTE_SUBMIX

mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.REMOTE_SUBMIX);

Android 10及以下的录屏

  目标  frameworks\av\services\audiopolicy\enginedefault\src\Engine.cpp

if(mAvailableOutputDevices.getDevice(AUDIO_DEVICE_OUT_REMOTE_SUBMIX, String8("0")) != 0) {
       device2 = availableOutputDeviceTypes & AUDIO_DEVICE_OUT_REMOTE_SUBMIX;
}

修改为

if (mAvailableOutputDevices.getDevice(AUDIO_DEVICE_OUT_REMOTE_SUBMIX, String8("0")) != 0) {
       device2 = availableOutputDeviceTypes & AUDIO_DEVICE_OUT_REMOTE_SUBMIX;
                               
       device2 |= (availableOutputDeviceTypes & AUDIO_DEVICE_OUT_WIRED_HEADPHONE);
                               
       device2 |= (availableOutputDeviceTypes & AUDIO_DEVICE_OUT_SPEAKER);
} 

Android 11

目标frameworks\av\services\audiopolicy\enginedefault\src\Engine.cpp

 if ((remoteSubmix = availableOutputDevices.getDevice(
                    AUDIO_DEVICE_OUT_REMOTE_SUBMIX, String8("0"),
                    AUDIO_FORMAT_DEFAULT)) != nullptr) {
                devices2.add(remoteSubmix);
            }

修改为

 if ((remoteSubmix = availableOutputDevices.getDevice(
                    AUDIO_DEVICE_OUT_REMOTE_SUBMIX, String8("0"),
                    AUDIO_FORMAT_DEFAULT)) != nullptr) {
				   devices2 = availableOutputDevices.getDevicesFromTypes({
                    AUDIO_DEVICE_OUT_REMOTE_SUBMIX, AUDIO_DEVICE_OUT_WIRED_HEADPHONE, AUDIO_DEVICE_OUT_SPEAKER});
            }

总结

	要实现安卓录制系统声音，正常情况下是获取不到的，本文采用的是修改源码的方式来实现。

相关资源: Android中实现录制内置声音