The AVCaptureVideoDataOutputSampleBufferDelegate is a protocol in the AVFoundation framework used for handling video frame data captured from the camera in real-time. This is particularly important for developers who are working on applications that require live video processing, such as augmented reality (AR), video recording, or real-time video effects. Understanding how to implement this delegate allows you to capture, process, and display video frames efficiently.

In this article, we will explore how to set up and implement the AVCaptureVideoDataOutputSampleBufferDelegate in an iOS application. We will cover the necessary steps, including setting up the capture session, configuring the video data output, and handling the captured video frames.

Examples:

1. Setting Up the Capture Session:

   First, you need to import the AVFoundation framework and set up the capture session.

   import AVFoundation
   import UIKit
   
   class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
      var captureSession: AVCaptureSession?
      var videoPreviewLayer: AVCaptureVideoPreviewLayer?
   
      override func viewDidLoad() {
          super.viewDidLoad()
          setupCaptureSession()
      }
   
      func setupCaptureSession() {
          captureSession = AVCaptureSession()
          guard let captureSession = captureSession else { return }
   
          captureSession.sessionPreset = .high
   
          guard let captureDevice = AVCaptureDevice.default(for: .video) else {
              print("Failed to get the camera device")
              return
          }
   
          do {
              let input = try AVCaptureDeviceInput(device: captureDevice)
              captureSession.addInput(input)
          } catch {
              print("Error setting up the input device: \(error)")
              return
          }
   
          let videoDataOutput = AVCaptureVideoDataOutput()
          videoDataOutput.setSampleBufferDelegate(self, queue: DispatchQueue(label: "videoQueue"))
          captureSession.addOutput(videoDataOutput)
   
          videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
          videoPreviewLayer?.videoGravity = .resizeAspectFill
          videoPreviewLayer?.frame = view.layer.bounds
          if let videoPreviewLayer = videoPreviewLayer {
              view.layer.addSublayer(videoPreviewLayer)
          }
   
          captureSession.startRunning()
      }
   
      func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
          // Process the sampleBuffer here
      }
   }

2. Handling Captured Video Frames:

   In the captureOutput method, you can process the video frames. For example, you might want to convert the sample buffer to a UIImage for further processing.

   func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
      guard let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return }
      let ciImage = CIImage(cvPixelBuffer: pixelBuffer)
      let context = CIContext()
      guard let cgImage = context.createCGImage(ciImage, from: ciImage.extent) else { return }
      let image = UIImage(cgImage: cgImage)
   
      // Perform any additional processing on the image
      DispatchQueue.main.async {
          // Update UI or other elements with the processed image
      }
   }

3. Stopping the Capture Session:

   To stop the capture session, you can call the stopRunning method on the AVCaptureSession instance.

   func stopCaptureSession() {
      captureSession?.stopRunning()
   }