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avkit

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Updated 10-16 05:52

About this skill

AVKit

High-level media playback UI built on AVFoundation. Provides system-standard video players, Picture-in-Picture, AirPlay routing, transport controls, and subtitle/caption display. Targets Swift 6.3 / iOS 26+.

Contents

  • Workflow
  • Route by Task
  • Core Decisions
  • Common Mistakes
  • Review Checklist
  • References

Workflow

  1. Define playback ownership, media source, audio-session policy, background behavior, and supported system controls.
  2. Choose AVPlayerViewController for full system playback UI or SwiftUI VideoPlayer for simpler embedding.
  3. Keep AVPlayer in stable state outside transient view initialization and observe readiness/errors deliberately.
  4. Configure Picture in Picture, AirPlay, Now Playing, subtitles, and seeking only when the product needs them.
  5. Verify interruptions, route changes, foreground/background transitions, PiP restoration, captions, and teardown.

Route by Task

  • Read core implementation details for audio session, player controllers, VideoPlayer, PiP, AirPlay, controls, and subtitles.
  • Read extended AVKit patterns for custom player UI, interstitials, background playback, error handling, and advanced hosting.

Core Decisions

  • Prefer system playback UI and delegation over subclassing AVPlayerViewController.
  • Configure the audio session for the intended playback/background contract.
  • Complete every PiP restoration callback and retain objects required by PiP.
  • Keep player identity and observation lifetime stable across SwiftUI body updates.

Common Mistakes

DON'T: Subclass AVPlayerViewController

Apple explicitly states this is unsupported. It may cause undefined behavior or crash on future OS versions.

// WRONG
class MyPlayerVC: AVPlayerViewController { } // Unsupported

// CORRECT: Use composition with delegation
let playerVC = AVPlayerViewController()
playerVC.delegate = coordinator

DON'T: Skip audio session configuration for PiP

PiP and background playback depend on the playback audio session category and the Audio, AirPlay, and Picture in Picture background mode.

// WRONG: Default audio session
let playerVC = AVPlayerViewController()
playerVC.player = player // PiP won't work

// CORRECT: Configure the category, then activate when playback starts
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .moviePlayback)
try AVAudioSession.sharedInstance().setActive(true)
let playerVC = AVPlayerViewController()
playerVC.player = player

DON'T: Forget the PiP restore delegate or its completion handler

Without restoreUserInterfaceForPictureInPictureStopWithCompletionHandler, the system cannot return the user to your player. Failing to call completionHandler(true) leaves the system in an inconsistent state.

// WRONG: No delegate method or missing completionHandler call
// User taps restore in PiP -> nothing happens or animation hangs

// CORRECT
func playerViewController(
    _ playerViewController: AVPlayerViewController,
    restoreUserInterfaceForPictureInPictureStopWithCompletionHandler completionHandler: @escaping (Bool) -> Void
) {
    present(playerViewController, animated: false) {
        completionHandler(true)
    }
}

DON'T: Create AVPlayer in a SwiftUI view's init

Creating the player eagerly causes performance issues. SwiftUI may recreate the view multiple times.

// WRONG: Created on every view init
struct PlayerView: View {
    let player = AVPlayer(url: videoURL) // Re-created on every view evaluation

    var body: some View { VideoPlayer(player: player) }
}

// CORRECT: Use @State and defer creation
struct PlayerView: View {
    @State private var player: AVPlayer?

    var body: some View {
        VideoPlayer(player: player)
            .task { player = AVPlayer(url: videoURL) }
    }
}

Review Checklist

  • Audio session category set to .playback with mode: .moviePlayback
  • Audio session activation deferred until playback begins
  • Audio, AirPlay, and Picture in Picture background mode added to UIBackgroundModes
  • AVPlayerViewController is not subclassed
  • PiP tested with supported video media, not only app/device setup
  • PiP restore delegate method implemented and calls completionHandler(true)
  • Custom PiP checks both device support and current isPictureInPicturePossible
  • Custom PiP starts only from explicit user interaction
  • AVPlayer deferred to .task in SwiftUI (not created eagerly)
  • canStartPictureInPictureAutomaticallyFromInline set for inline players
  • requiresLinearPlayback toggled only during required ad/legal segments
  • tvOS-only skipping APIs are not used for iOS transport controls
  • External playback is not disabled accidentally when AirPlay is required
  • Subtitle selection tested with actual media tracks
  • Video gravity set appropriately (.resizeAspect vs .resizeAspectFill)
  • isReadyForDisplay observed before showing the player view
  • Error handling for network-streamed content (HLS failures, timeouts)

References