AVCaptureSession+Extensions.swift

import Foundation
import AVFoundation

extension AVCaptureSession {
    
    func setup(deviceInput: AVCaptureDeviceInput = .defaultDevice,
               delegate: AVCaptureVideoDataOutputSampleBufferDelegate) {
        self.beginConfiguration()
        self.sessionPreset = .vga640x480
        guard self.canAddInput(deviceInput) else {
            print("Could not add video device input")
            self.commitConfiguration()
            return
        }
        self.addInput(deviceInput)
        self.addOutput(delegate)
        self.commitConfiguration()
    }
    
    func addOutput(_ delegate: AVCaptureVideoDataOutputSampleBufferDelegate) {
        let videoDataOutput = AVCaptureVideoDataOutput()
        let videoDataOutputQueue = DispatchQueue(label: "VideoDataOutput",
                                                 qos: .userInitiated, attributes: [],
                                                 autoreleaseFrequency: .workItem)
        guard self.canAddOutput(videoDataOutput) else {
            fatalError("Could not add video data output to the self")
        }
        self.addOutput(videoDataOutput)
        videoDataOutput.alwaysDiscardsLateVideoFrames = true
        videoDataOutput.videoSettings = [
            kCVPixelBufferPixelFormatTypeKey as String:
                Int(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)]
        videoDataOutput.setSampleBufferDelegate(delegate, queue: videoDataOutputQueue)
        let captureConnection = videoDataOutput.connection(with: .video)
        captureConnection?.isEnabled = true
    }
}