what you see is what you get in AVCaptureVideoPreviewLayer

I created AVCaptureVideoPreviewLayer to get the video stream, videoGravity = AVLayerVideoGravityResizeAspectFill. But in the method - (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection returns. I found that the actual conversion into UIImage is not what the user sees in AVCaptureVideoPreviewLayer, it is much more than what the user sees in AVCaptureVideoPreviewLayer, how can I get the sampleBuffer that the user sees in AVCaptureVideoPreviewLayer