As of iOS 18, as far as I can tell, it appears there's still no AVPlayer options that allow users to toggle the caption / subtitle track on and off. Does anyone know of a way to do this with AVPlayer or with SwiftUI's VideoPlayer?
The following code reproduces this issue. It can be pasted into an app playground. This is a random video and a random vtt file I found on the internet.
import SwiftUI
import AVKit
import UIKit
struct ContentView: View {
private let video = URL(string: "https://server15700.contentdm.oclc.org/dmwebservices/index.php?q=dmGetStreamingFile/p15700coll2/15.mp4/byte/json")!
private let captions = URL(string: "https://gist.githubusercontent.com/samdutton/ca37f3adaf4e23679957b8083e061177/raw/e19399fbccbc069a2af4266e5120ae6bad62699a/sample.vtt")!
@State private var player: AVPlayer?
var body: some View {
VStack {
VideoPlayerView(player: player)
.frame(maxWidth: .infinity, maxHeight: 200)
}
.task {
// Captions won't work for some reason
player = try? await loadPlayer(video: video, captions: captions)
}
}
}
private struct VideoPlayerView: UIViewControllerRepresentable {
let player: AVPlayer?
func makeUIViewController(context: Context) -> AVPlayerViewController {
let controller = AVPlayerViewController()
controller.player = player
controller.modalPresentationStyle = .overFullScreen
return controller
}
func updateUIViewController(_ uiViewController: AVPlayerViewController, context: Context) {
uiViewController.player = player
}
}
private func loadPlayer(video: URL, captions: URL?) async throws -> AVPlayer {
let videoAsset = AVURLAsset(url: video)
let videoPlusSubtitles = AVMutableComposition()
try await videoPlusSubtitles.add(videoAsset, withMediaType: .video)
try await videoPlusSubtitles.add(videoAsset, withMediaType: .audio)
if let captions {
let captionAsset = AVURLAsset(url: captions)
// Must add as .text. .closedCaption and .subtitle don't work?
try await videoPlusSubtitles.add(captionAsset, withMediaType: .text)
}
return await AVPlayer(playerItem: AVPlayerItem(asset: videoPlusSubtitles))
}
private extension AVMutableComposition {
func add(_ asset: AVAsset, withMediaType mediaType: AVMediaType) async throws {
let duration = try await asset.load(.duration)
try await asset.loadTracks(withMediaType: mediaType).first.map { track in
let newTrack = self.addMutableTrack(withMediaType: mediaType, preferredTrackID: kCMPersistentTrackID_Invalid)
let range = CMTimeRangeMake(start: .zero, duration: duration)
try newTrack?.insertTimeRange(range, of: track, at: .zero)
}
}
}
