IOS: how to apply brightness to AVCapturesession

I am making an application where I started AVCaptureSession. I opened the front camera. Now I want to apply brightness to avcapturesession.

AVCaptureSession *session = [AVCaptureSession new];
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone)
    [session setSessionPreset:AVCaptureSessionPresetHigh];
else
    [session setSessionPreset:AVCaptureSessionPresetPhoto];

AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
require( error == nil, bail );
{
if ( [session canAddInput:deviceInput] )
    [session addInput:deviceInput];

stillImageOutput = [AVCaptureStillImageOutput new];
    NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
    [stillImageOutput setOutputSettings:outputSettings];

[stillImageOutput addObserver:self forKeyPath:@"capturingStillImage" options:NSKeyValueObservingOptionNew context:(__bridge void *)(AVCaptureStillImageIsCapturingStillImageContext)];
if ( [session canAddOutput:stillImageOutput] )
    [session addOutput:stillImageOutput];

    [[stillImageOutput connectionWithMediaType:AVMediaTypeVideo] setEnabled:YES];

videoDataOutput = [AVCaptureVideoDataOutput new];

NSDictionary *rgbOutputSettings = [NSDictionary dictionaryWithObject:
                                   [NSNumber numberWithInt:kCMPixelFormat_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
[videoDataOutput setVideoSettings:rgbOutputSettings];
[videoDataOutput setAlwaysDiscardsLateVideoFrames:YES];
videoDataOutputQueue = dispatch_queue_create("VideoDataOutputQueue", DISPATCH_QUEUE_SERIAL);
[videoDataOutput setSampleBufferDelegate:self queue:videoDataOutputQueue];
if ( [session canAddOutput:videoDataOutput] )
    [session addOutput:videoDataOutput];
[[videoDataOutput connectionWithMediaType:AVMediaTypeVideo] setEnabled:YES];

effectiveScale = 1.0;
chromeLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[chromeLayer setBackgroundColor:[[UIColor blackColor] CGColor]];
[chromeLayer setVideoGravity:AVLayerVideoGravityResizeAspect];
CALayer *rootLayer = [chromeView layer];
[rootLayer setMasksToBounds:YES];
[chromeLayer setFrame:CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y, self.view.frame.size.width, self.view.frame.size.height)];
[rootLayer addSublayer:chromeLayer];
[session startRunning];

      

        
        
        
      

    

I have implemented delegates and datasource related to avcapturesession. Any help is appreciated.