SwiftUI-AVVideoComposition.swift

import SwiftUI
import AVKit
import CoreImage
import CoreImage.CIFilterBuiltins


struct ContentView: View {

    @State private var currentFilter = 0
    var filters : [CIFilter?] = [nil, CIFilter.sepiaTone(), CIFilter.pixellate(), CIFilter.comicEffect()]
    let player = AVPlayer(url: Bundle.main.url(forResource: "tennis", withExtension: "mp4")!)

    var body: some View {
        
        VStack{

        VideoPlayer(player: player)
            .onAppear{
                player.currentItem!.videoComposition = AVVideoComposition(asset: player.currentItem!.asset,  applyingCIFiltersWithHandler: { request in

                    if let filter = self.filters[currentFilter]{
                    
                    let source = request.sourceImage.clampedToExtent()
                    filter.setValue(source, forKey: kCIInputImageKey)

                    if filter.inputKeys.contains(kCIInputScaleKey){
                        filter.setValue(30, forKey: kCIInputScaleKey)
                    }

                    let output = filter.outputImage!.cropped(to: request.sourceImage.extent)
                    request.finish(with: output, context: nil)
                    }
                    else{
                        request.finish(with: request.sourceImage, context: nil)
                    }
                })
            }
            
            Picker(selection: $currentFilter, label: Text("Select Filter")) {
                ForEach(0..<filters.count) { index in
                    Text(self.filters[index]?.name ?? "None").tag(index)
                }
            }.pickerStyle(SegmentedPickerStyle())
            
            Text("Value: \(self.filters[currentFilter]?.name ?? "None")")
        }
    }
}