Call recording with OpenSL

Question

I try to fix call recording in my app since lolipop update in my Galaxy S5. As a base I am using google sample project from here: Sample.

And this is the main part of the code:

AudioRecorder::AudioRecorder(SampleFormat *sampleFormat, SLEngineItf slEngine) :freeQueue_(nullptr), recQueue_(nullptr), devShadowQueue_(nullptr), callback_(nullptr)

SLresult result;
sampleInfo_ = *sampleFormat;
SLAndroidDataFormat_PCM_EX format_pcm;
ConvertToSLSampleFormat(&format_pcm, &sampleInfo_);

gFp = fopen("/storage/emulated/0/file.pcm", "w");

// configure audio source
SLDataLocator_IODevice loc_dev = {SL_DATALOCATOR_IODEVICE, SL_IODEVICE_AUDIOINPUT,
                                  SL_DEFAULTDEVICEID_AUDIOINPUT, NULL};
SLDataSource audioSrc = {&loc_dev, NULL};


// configure audio sink
SLDataLocator_AndroidSimpleBufferQueue loc_bq = {
        SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE,
        DEVICE_SHADOW_BUFFER_QUEUE_LEN};

SLDataSink audioSnk = {&loc_bq, &format_pcm};

// create audio recorder
// (requires the RECORD_AUDIO permission)
const SLInterfaceID id[2] = {SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
                             SL_IID_ANDROIDCONFIGURATION};

const SLboolean req[2] = {SL_BOOLEAN_FALSE, SL_BOOLEAN_FALSE};

result = (*slEngine)->CreateAudioRecorder(slEngine,
                                          &recObjectItf_,
                                          &audioSrc,
                                          &audioSnk,
                                          2,
                                          id, req);
SLASSERT(result);

// Configure the voice recognition preset which has no
// signal processing for lower latency.
SLAndroidConfigurationItf inputConfig;
result = (*recObjectItf_)->GetInterface(recObjectItf_,
                                        SL_IID_ANDROIDCONFIGURATION,
                                        &inputConfig);

SLuint32 presetValue = SL_ANDROID_RECORDING_PRESET_VOICE_COMMUNICATION;
result = (*inputConfig)->SetConfiguration(inputConfig,
                                          SL_ANDROID_KEY_RECORDING_PRESET,
                                          &presetValue,
                                          sizeof(SLint32));
SLASSERT(result);


result = (*recObjectItf_)->Realize(recObjectItf_, SL_BOOLEAN_FALSE);
SLASSERT(result);

result = (*recObjectItf_)->GetInterface(recObjectItf_, SL_IID_RECORD, &recItf_);
SLASSERT(result);

result = (*recObjectItf_)->GetInterface(recObjectItf_, SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
                                        &recBufQueueItf_);
SLASSERT(result);

result = (*recBufQueueItf_)->RegisterCallback(recBufQueueItf_, bqRecorderCallback, this);
SLASSERT(result);

devShadowQueue_ = new AudioQueue(DEVICE_SHADOW_BUFFER_QUEUE_LEN);
assert(devShadowQueue_);

And here is my problem this code do not record other side of the call, in output file I can only hear voice from microphone. I tried changing parameters but with same result. Anyone know what I am doing wrong?

Answer 1

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

Answer 2

I found the solution to fix Galaxy S5 call recording.

Main thing is to call this: status_t AudioSystem::setParameters(audio_io_handle_t ioHandle, const String8& keyValuePairs) in the loop when the call is started.

First get the desired function:

open_media = dlopen("/system/lib/libmedia.so", RTLD_LAZY);

set_parameters = (int (*)(int, void *)) dlsym(open_media,
                                                  "_ZN7android11AudioSystem13setParametersEiRKNS_7String8E");

Next we need audio_io_handle_t and String8& object:

1. audio_io_handle_t- is audio session id increased by 1, You can get it from AudioRecord.getAudioSessionId

2. String8& this is more difficult:

   //First inicialize function 
   create_string = (void (*)(void *, const char *)) dlsym(open_util, 
   "_ZN7android7String8C2EPKc");
   
   //next call this function to convert string to required object 
   create_string(&str8, str);
   

When we have all needed parts we can call setParameters function:

//remember to call this in loop when recording is starting
set_parameters(id + 1, &str8);

That how variable declaration looks:

int (*set_parameters)(int, void *);

void (*create_string)(void *, const char *);

void *str8 = 0;
const char *str = "input_source=4";

@ChanchalShelar

---

@Peter @AkshatVajpayee

This is how my .cpp file looks:

void *open_media;
void *open_util;

int (*set_parameters)(int, void *);

void (*create_string)(void *, const char *);

void *str8 = 0;
const char *str = "input_source=4";


extern "C" {
    JNIEXPORT bool JNICALL
    Java_com_sample_NativeAudio_init(JNIEnv *env, jclass);
    JNIEXPORT int JNICALL
    Java_com_sample_NativeAudio_setParameters(JNIEnv *env, jclass, int id);
}


void get_string8() {
    create_string = (void (*)(void *, const char *)) dlsym(open_util, "_ZN7android7String8C2EPKc");

    if (!create_string) {
        LOGD("There is no create_string function");
    } else {
        LOGD("create_string function OK");
    }

    create_string(&str8, str);
    if (!str8) {
        LOGD("Filed to create str8");
    } else {
        LOGD("create str8 success");
    }

}

JNIEXPORT int JNICALL Java_com_sample_NativeAudio_setParameters(JNIEnv *env,
                                                                  jclass     type, int id) {
    if (set_parameters) {
        return set_parameters(id + 1, &str8);
    }

    return 0;
}


JNIEXPORT bool JNICALL Java_com_sample_NativeAudio_init(JNIEnv *env, jclass type) {

    open_util = dlopen("/system/lib/libutils.so", RTLD_LAZY);

    if (open_util) {
        get_string8();
    } else {
        return false;
    }

    open_media = dlopen("/system/lib/libmedia.so", RTLD_LAZY);

    if (open_media) {
        set_parameters = (int (*)(int, void *)) dlsym(open_media,
                                              "_ZN7android11AudioSystem13setParametersEiRKNS_7String8E");
    } else {
        return false;
    }

    return true;
}