Android中实现对内置声源的录制有两种方案
一、将应用打包为系统应用
AudioSource输入源
public final class AudioSource {
private AudioSource() {}
/** Default audio source **/
public static final int DEFAULT = 0;
/** Microphone audio source */
public static final int MIC = 1;
/** Voice call uplink (Tx) audio source */
public static final int VOICE_UPLINK = 2;
/** Voice call downlink (Rx) audio source */
public static final int VOICE_DOWNLINK = 3;
/** Voice call uplink + downlink audio source */
public static final int VOICE_CALL = 4;
/** Microphone audio source with same orientation as camera if available, the main
* device microphone otherwise */
public static final int CAMCORDER = 5;
public static final int VOICE_RECOGNITION = 6;
public static final int VOICE_COMMUNICATION = 7;
public static final int REMOTE_SUBMIX = 8;
}
- DEFAULT:默认为MIC,android.permission.RECORD_AUDIO
- MIC:麦克风,android.permission.RECORD_AUDIO
- VOICE_UPLINK:电话录音上行线路,android.permission.CAPTURE_AUDIO_OUTPUT,系统权限不允许第三方app使用
- VOICE_DOWNLINK:电话录音下行线路,android.permission.CAPTURE_AUDIO_OUTPUT,系统权限不允许第三方app使用
- VOICE_CALL:电话录音上下线路,android.permission.CAPTURE_AUDIO_OUTPUT,系统权限不允许第三方app使用
- CAMCORDER:摄像头的麦克风,android.permission.RECORD_AUDIO
- VOICE_RECOGNITION:语音识别,android.permission.RECORD_AUDIO
- VOICE_COMMUNICATION:网络电话,android.permission.RECORD_AUDIO
- REMOTE_SUBMIX:传输到远程的音频混合流,默认情况下如果用该项录音,本地扬声器或者耳机的声音将会被截走,android.permission.CAPTURE_AUDIO_OUTPUT,系统权限不允许第三方app使用
REMOTE_SUBMIX可以实现内录功能,有两点比较麻烦:
(1)需要系统权限
(2)会截走扬声器和耳机的声音,也就是说再录音时本地无法播放声音
- 对于系统权限,需要在在AndroidManifest.xml添加
android:sharedUserId="android.uid.system",然后使用系统签名来打包应用,这样就第三方应用打包为系统应用,就可以使用系统权限了。
https://github.com/aosp-mirror/platform_build/tree/master/target/product/security
用signapk.jar对应用进行签名
java -jar signapk.jar platform.x509.pem platform.pk8 app-unsigned.apk signed.apk
signapk获取地址:
https://github.com/techexpertize/SignApk
https://github.com/maks/aosp-signapk
- 对于截走扬声器和耳机的声音问题
修改framework下av/services/audiopolicy/AudioPolicyManager.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);
}
现在就可以使用MediaRecorder.AudioSource.REMOTE_SUBMIX实现内录功能了。
该方案只适用于知道系统签名或者自己编译系统源码的情况
参考文章:
https://www.jianshu.com/p/916ede1d1f48
https://blog.csdn.net/liuhaitao_share/article/details/41249175
https://blog.csdn.net/jinzhuojun/article/details/33748031
二、使用Root权限修改底层驱动
第二种方法来自开源项目:
https://github.com/iwo/SCR-Screen-Recorder-app