Photokit

# AV Playback

Patterns for media playback with AVPlayer, streaming HLS content, audio
session configuration, background audio, Now Playing integration, remote
command handling, and Picture-in-Picture.

## Contents

- [AVPlayer and AVPlayerViewController Setup](#avplayer-and-avplayerviewcontroller-setup)
- [AVPlayerItem and AVAsset Loading](#avplayeritem-and-avasset-loading)
- [Playback Controls](#playback-controls)
- [Observing Player State and Time](#observing-player-state-and-time)
- [Streaming HLS Content](#streaming-hls-content)
- [AVAudioSession Configuration](#avaudiosession-configuration)
- [Background Audio Setup](#background-audio-setup)
- [Now Playing Info Center](#now-playing-info-center)
- [MPRemoteCommandCenter](#mpremotecommandcenter)
- [Picture-in-Picture](#picture-in-picture)

## AVPlayer and AVPlayerViewController Setup

`AVPlayer` manages playback of a single media asset. Use
`AVPlayerViewController` (AVKit) for the system-standard playback UI with
transport controls, or `AVPlayerLayer` for a custom player interface.

Docs: [AVPlayer](https://sosumi.ai/documentation/avfoundation/avplayer),
[AVPlayerViewController](https://sosumi.ai/documentation/avkit/avplayerviewcontroller)

### AVPlayerViewController in SwiftUI

```swift
import SwiftUI
import AVKit

struct VideoPlayerView: View {
    let url: URL
    @State private var player: AVPlayer?

    var body: some View {
        VideoPlayer(player: player)
            .onAppear {
                player = AVPlayer(url: url)
                player?.play()
            }
            .onDisappear {
                player?.pause()
                player = nil
            }
    }
}
```

### AVPlayerViewController in UIKit

```swift
import UIKit
import AVKit

final class VideoViewController: UIViewController {
    private var player: AVPlayer?

    func presentVideo(url: URL) {
        player = AVPlayer(url: url)
        let controller = AVPlayerViewController()
        controller.player = player
        present(controller, animated: true) {
            self.player?.play()
        }
    }
}
```

### Custom Player with AVPlayerLayer

For full control over the player UI, embed an `AVPlayerLayer`:

```swift
import AVFoundation
import UIKit

final class PlayerView: UIView {
    override class var layerClass: AnyClass { AVPlayerLayer.self }

    var playerLayer: AVPlayerLayer { layer as! AVPlayerLayer }

    var player: AVPlayer? {
        get { playerLayer.player }
        set { playerLayer.player = newValue }
    }

    func configure() {
        playerLayer.videoGravity = .resizeAspect
    }
}
```

## AVPlayerItem and AVAsset Loading

`AVAsset` represents the static media (duration, tracks, metadata).
`AVPlayerItem` adds the dynamic state (current time, buffering status) needed
for playback.

Docs: [AVPlayerItem](https://sosumi.ai/documentation/avfoundation/avplayeritem),
[AVAsset](https://sosumi.ai/documentation/avfoundation/avasset)

```swift
import AVFoundation

// Local file
let localURL = Bundle.main.url(forResource: "intro", withExtension: "mp4")!
let localItem = AVPlayerItem(url: localURL)

// Remote file
let remoteURL = URL(string: "https://example.com/video.mp4")!
let remoteItem = AVPlayerItem(url: remoteURL)

// From an existing AVAsset (for more control)
let asset = AVURLAsset(url: remoteURL, options: [
    AVURLAssetPreferPreciseDurationAndTimingKey: true
])

// Load properties asynchronously before playback (iOS 15+)
let duration = try await asset.load(.duration)
let tracks = try await asset.load(.tracks)
let isPlayable = try await asset.load(.isPlayable)

let item = AVPlayerItem(asset: asset)
let player = AVPlayer(playerItem: item)
```

### Replacing the Current Item

Reuse a single `AVPlayer` and swap items:

```swift
let nextItem = AVPlayerItem(url: nextVideoURL)
player.replaceCurrentItem(with: nextItem)
player.play()
```

### Queue Playback with AVQueuePlayer

```swift
let items = videoURLs.map { AVPlayerItem(url: $0) }
let queuePlayer = AVQueuePlayer(items