Creating a seamless multiview playback experience

At a glance

Project structure

MultiviewPlaybackSampleApp/
├── MultiviewPlaybackSampleAppApp.swift  # Composition root
├── Menu.json                            # Stream configuration
├── Models/
│   ├── Menu.swift                       # Codable menu values
│   └── PlayerState.swift                # One player and its state
├── ViewModels/
│   ├── MainViewModel.swift              # Menu/navigation state
│   └── LayoutGridViewModel.swift        # Multi-player coordination
├── Views/
│   ├── MainView.swift
│   ├── GridView.swift / LayoutView.swift
│   ├── LayoutGridView.swift / PlayerView.swift
│   └── PlayerViewController.swift       # AVKit bridge
└── Utilities/                           # Decode, logging, URL, and style helpers

Structure observations

• Folder names express architectural role; feature-specific names connect views to their view models.
• LayoutGridViewModel is the aggregate owner for a screenful of players, while PlayerState owns one player’s framework behavior.
• JSON decoding and framework-value conversion live in small extensions rather than either view model.

Overall architecture

flowchart LR
    App["App"] --> MainVM["MainViewModel"]
    App --> MainView["MainView"]
    MainView --> LayoutVM["LayoutGridViewModel"]
    LayoutVM --> States["PlayerState × N"]
    States --> Players["AVPlayer × N"]
    LayoutVM --> Medium["AVPlaybackCoordinationMedium"]
    States --> Arbiter["AVRoutingPlaybackArbiter.shared"]
    MainView --> AVKit["AVPlayerViewController adapter"]

Reference code

MultiviewPlaybackSampleApp/MultiviewPlaybackSampleAppApp.swift:11 and MultiviewPlaybackSampleApp/Views/MainView.swift:31 — two-level composition

let mainViewModel = MainViewModel.createViewModelWithMenu
MainView(viewModel: mainViewModel)

// When a playback mode is selected:
layoutGridViewModel = LayoutGridViewModel(selectedItem: viewModel.menuItem)
viewModel.showGridView()

Interpretation

The app creates long-lived menu state, while MainView creates a fresh layout coordinator for each playback destination. That coordinator creates and manages the player collection. PlayerState translates layout-level intent into AVFoundation and AVRouting operations.

Ownership and state

classDiagram
    MultiviewPlaybackSampleAppApp *-- MainViewModel : creates
    MainView *-- LayoutGridViewModel : creates as State
    LayoutGridViewModel *-- PlayerState : creates many
    LayoutGridViewModel *-- AVPlaybackCoordinationMedium : creates
    PlayerState *-- AVPlayer : lazy creates
    PlayerState o-- AVRoutingPlaybackArbiter : shared
    PlayerViewController --> PlayerState : receives

Ownership evidence

MultiviewPlaybackSampleApp/ViewModels/LayoutGridViewModel.swift:53 — layout-owned players

func createAllPlayers() {
    resetValues()
    for (index, asset) in selectedItem.assets.enumerated() {
        let playerState = PlayerState(/* asset values */)
        playerState.connectToAVFCoordinationMedium(
            coordinationMedium: coordinationMedium
        )
        playersToShow.append(playerState)
    }
}

Class and protocol design

MultiviewPlaybackSampleApp/Models/Menu.swift:11 — protocol composition for data models

typealias DataModel = (Codable & Equatable & Sendable)

struct MenuItem: DataModel, Identifiable { /* immutable fields */ }
struct MenuAsset: DataModel, Identifiable, Hashable { /* ... */ }

There is protocol composition for value models, but no app-defined playback protocol. The player collaborators are concrete.

Access control

Reference code

MultiviewPlaybackSampleApp/Models/PlayerState.swift:17 — broad observable surface with one private detail

let assetURL: URL
var playerRate: Float = 0
var isFocusPlayer = false
var isFullScreen = false
private let queue = DispatchQueue(label: "com.apple...PlayerState.queue")

Logic ownership and placement

Design patterns

Naming conventions

• Role suffixes are consistent: View, ViewModel, State, and ViewController.
• Collection-level methods name their scope: createAllPlayers, setFocusOnPlayer, and setFullScreenPlayer.
• Boolean properties use is/should: isFocusPlayer, isFullScreen, shouldBeHidden.
• Extension files use Type+Additions.swift; view files match their primary type.

Architecture takeaways

• Model a multi-player screen with one collection coordinator and one state owner per player.
• Share a playback coordination medium while keeping player cleanup local.
• A view adapter is an effective boundary between declarative SwiftUI and AVPlayerViewController.
• If this grew beyond a sample, private(set) and playback protocols would enforce the ownership already implied by call sites.

Source map

• Official Apple documentation