cameraVideoScreenShot.m

- (void)setupCaptureSession 
{
    NSError *error = nil;
    AVCaptureSession *session = [[AVCaptureSession alloc] init];

    session.sessionPreset = AVCaptureSessionPresetMedium;

    AVCaptureDevice *device = [AVCaptureDevice
                           defaultDeviceWithMediaType:AVMediaTypeVideo];

    AVCaptureDeviceInput *input = [AVCaptureDeviceInput 
                                     deviceInputWithDevice:device 
                                                     error:&error];
    if (!input) {
        // Handling the error appropriately
    }
    [session addInput:input];

    AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] 
                                                                   init];
    [session addOutput:output];

    dispatch_queue_t queue = dispatch_queue_create("myQueue", NULL);
    [output setSampleBufferDelegate:self queue:queue];
    dispatch_release(queue);

    output.videoSettings = 
                [NSDictionary dictionaryWithObject:
                    [NSNumber numberWithInt:kCVPixelFormatType_32BGRA] 
                    forKey:(id)kCVPixelBufferPixelFormatTypeKey];

    output.minFrameDuration = CMTimeMake(1, 15);

    [session startRunning];
    [self setSession:session];
}

- (void)captureOutput:(AVCaptureOutput *)captureOutput 
         didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
         fromConnection:(AVCaptureConnection *)connection
{ 
    UIImage *image = [self imageFromSampleBuffer:sampleBuffer];

     < Add your code here that uses the image >

}

- (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sample
{
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sample); 
    CVPixelBufferLockBaseAddress(imageBuffer, 0); 

    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer); 

    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
    size_t width = CVPixelBufferGetWidth(imageBuffer); 
    size_t height = CVPixelBufferGetHeight(imageBuffer); 

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

    CGContextRef context = CGBitmapContextCreate(baseAddress, width, 
                                               height, 8, 
                                             bytesPerRow, colorSpace, 
                                          kCGBitmapByteOrder32Little | 
                                       kCGImageAlphaPremultipliedFirst); 
    CGImageRef quartzImage = CGBitmapContextCreateImage(context); 
    CVPixelBufferUnlockBaseAddress(imageBuffer,0);

    CGContextRelease(context); 
    CGColorSpaceRelease(colorSpace);

    UIImage *image = [UIImage imageWithCGImage:quartzImage];

    CGImageRelease(quartzImage);

    return (image);
}