Android Call Recording Incoming voice not getting recorded

Xiaomi devices always have problems with permission request even run-time or install-time.

I have an Xiaomi Redmi 3 pro, and it always force to Deny some permission when I install apps, so I must manually Allow it. If your problem is the same, I found some workaround solution and it worked for me: How to get MIUI Security app auto start permission programmatically?

You need to use ndk. Here are examples of the functions that need to be done.

Load libmedia.so and libutils.so

int load(JNIEnv *env, jobject thiz) {
    void *handleLibMedia;
    void *handleLibUtils;
    int result = -1;
    lspr func = NULL;

    pthread_t newthread = (pthread_t) thiz;

    handleLibMedia = dlopen("libmedia.so", RTLD_NOW | RTLD_GLOBAL);
    if (handleLibMedia != NULL) {
        func = dlsym(handleLibMedia, "_ZN7android11AudioSystem13setParametersEiRKNS_7String8E");
        if (func != NULL) {
            result = 0;
        }
        audioSetParameters = (lasp) func;
    } else {
        result = -1;
    }

    handleLibUtils = dlopen("libutils.so", RTLD_NOW | RTLD_GLOBAL);
    if (handleLibUtils != NULL) {
        fstr = dlsym(handleLibUtils, "_ZN7android7String8C2EPKc");
        if (fstr == NULL) {
            result = -1;
        }
    } else {
        result = -1;
    }

    cmd = CM_D;

    int resultTh = pthread_create(&newthread, NULL, taskAudioSetParam, NULL);

    return result;}

Function setParameters

int setParam(jint i, jint as) {
pthread_mutex_lock(&mt);

audioSession = (int) (as + 1);

kvp = "input_source=4";
kvps = toString8(kvp);

cmd = (int) i;

pthread_cond_signal(&cnd);
pthread_mutex_unlock(&mt);

return 0;}

Task AudioSetParameters

void *taskAudioSetParam(void *threadid) {
    while (1) {
        pthread_mutex_lock(&mt);
        if (cmd == CM_D) {
            pthread_cond_wait(&cnd, &mt);
        } else if (audioSetParameters != NULL) {
             audioSetParameters(audioSession, kvps);
        }
        pthread_mutex_unlock(&mt);
    }
}

There is a library and an example of use https://github.com/ViktorDegtyarev/CallRecLib

First these 3 permissions are needed in Manifest as well as a runtime permission request if the device is above Marshmallow,

<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.CAPTURE_AUDIO_OUTPUT" />

2. MediaRecorder.AudioSource.VOICE_CALL is not supported on all phones so you need to continue using MediaRecorder.AudioSource.MIC.

I use this and works fine on most of the devices,

      recorder = new MediaRecorder();
      recorder.setAudioSource(audioSource);
      recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
      recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
      recorder.setOutputFile(your_path);

3. You need to set this to record your calls properly,

   audioManager.setMode(AudioManager.MODE_IN_CALL);

raise volume level when you start recording

audioManager.setStreamVolume(AudioManager.STREAM_VOICE_CALL,audioManager.getStreamMaxVolume(AudioManager.STREAM_VOICE_CALL), 0);

When you stop recording set the mode to normal, audioManager.setMode(AudioManager.MODE_NORMAL); and also set the stream volume to back how it was.