Remote IO Audio Unit is not capturing audio from speaker or remote stream

Question

I am using following code to record audio and writing it in file

- (void) initializeOutputUnit
{
    OSStatus status;

    // Describe audio component
    AudioComponentDescription desc;
    desc.componentType = kAudioUnitType_Output;
    desc.componentSubType = kAudioUnitSubType_RemoteIO;
    desc.componentFlags = 0;
    desc.componentFlagsMask = 0;
    desc.componentManufacturer = kAudioUnitManufacturer_Apple;

    // Get component
    AudioComponent inputComponent = AudioComponentFindNext(NULL, &desc);

    // Get audio units
    status = AudioComponentInstanceNew(inputComponent, &mAudioUnit);

    // Enable IO for recording
    UInt32 flag = 1;

    //bhoomi
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioOutputUnitProperty_EnableIO,
                                  kAudioUnitScope_Input,
                                  kInputBus,
                                  &flag,
                                  sizeof(flag));




    // Enable IO for playback
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioOutputUnitProperty_EnableIO,
                                  kAudioUnitScope_Output,
                                  kOutputBus,
                                  &flag,
                                  sizeof(flag));

    // Describe format
    AudioStreamBasicDescription audioFormat={0};
    audioFormat.mSampleRate         = kSampleRate;
    audioFormat.mFormatID           = kAudioFormatLinearPCM;
    audioFormat.mFormatFlags        = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    audioFormat.mFramesPerPacket    = 1;
    audioFormat.mChannelsPerFrame   = 1;
    audioFormat.mBitsPerChannel     = 16;
    audioFormat.mBytesPerPacket     = 2;
    audioFormat.mBytesPerFrame      = 2;

    // Apply format
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_StreamFormat,
                                  kAudioUnitScope_Output,
                                  kInputBus,
                                  &audioFormat,
                                  sizeof(audioFormat));
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_StreamFormat,
                                  kAudioUnitScope_Input,
                                  kOutputBus,
                                  &audioFormat,
                                  sizeof(audioFormat));


    // Set input callback
    AURenderCallbackStruct callbackStruct;
    callbackStruct.inputProc = recordingCallback;
    callbackStruct.inputProcRefCon = (__bridge void *)self;

    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioOutputUnitProperty_SetInputCallback,
                                  kAudioUnitScope_Global,
                                  kInputBus,
                                  &callbackStruct,
                                  sizeof(callbackStruct));


    // Disable buffer allocation for the recorder (optional - do this if we want to pass in our own)
    flag = 0;
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_ShouldAllocateBuffer,
                                  kAudioUnitScope_Output,
                                  kInputBus,
                                  &flag,
                                  sizeof(flag));

    // On initialise le fichier audio
    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *destinationFilePath = [[NSString alloc] initWithFormat: @"%@/output.caf", documentsDirectory];
    NSLog(@">>> %@\n", destinationFilePath);

    CFURLRef destinationURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, (__bridge CFStringRef)destinationFilePath, kCFURLPOSIXPathStyle, false);

    OSStatus setupErr = ExtAudioFileCreateWithURL(destinationURL, kAudioFileCAFType, &audioFormat, NULL, kAudioFileFlags_EraseFile, &mAudioFileRef);
    CFRelease(destinationURL);
    NSAssert(setupErr == noErr, @"Couldn't create file for writing");

    setupErr = ExtAudioFileSetProperty(mAudioFileRef, kExtAudioFileProperty_ClientDataFormat, sizeof(AudioStreamBasicDescription), &audioFormat);
    NSAssert(setupErr == noErr, @"Couldn't create file for format");

    setupErr =  ExtAudioFileWriteAsync(mAudioFileRef, 0, NULL);
    NSAssert(setupErr == noErr, @"Couldn't initialize write buffers for audio file");

    CheckError(AudioUnitInitialize(mAudioUnit), "AudioUnitInitialize");
    CheckError(AudioOutputUnitStart(mAudioUnit), "AudioOutputUnitStart");

  //  [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(stopRecording:) userInfo:nil repeats:NO];


}

In my application I have video call functionality using webRTC. Above code is working fine with mic audio, mic audio is recorded properly but i am not able to record speaker sound(remote audio stream). Is it possible to record both sound (mic and speaker) in same file?.If yes, then how to modify code so it will also record sound from internal iphone speakers.