Providing an integrated view of your timeline when playing HLS interstitials

At a glance

Project structure

Source bundle/
└── HLSInterstitialDemo/
    └── HLSInterstitialDemo/
        ├── HLSInterstitialDemoApp.swift
        ├── Menu/
        │   ├── ViewModels/
        │   │   ├── MenuItemViewModel.swift
        │   │   ├── MenuItemLauncherViewModel.swift
        │   │   ├── MenuSectionViewModel.swift
        │   │   └── MenuViewModel.swift
        │   └── Models/
        │       └── Menu.swift
        ├── Helpers/
        │   └── ModalPresentationCoordinator.swift
        ├── IntegratedTimeline/
        │   ├── IntegratedTimelinePlayerView.swift
        │   ├── IntegratedTimelinePlayingView.swift
        │   └── Controls/
        │       ├── ControlButtonStyleView.swift
        │       └── PlaybackControlsView.swift
        └── SharePlay/
            └── SharePlayCoordinator.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 4 project/configuration file(s) and 42 source declaration(s).

Overall architecture

flowchart LR
    N1["HLSInterstitialDemoApp"]
    N2["MenuView"]
    N3["ContentViewModel"]
    N4["AVFoundation APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

HLSInterstitialDemo/HLSInterstitialDemo/HLSInterstitialDemoApp.swift:9 — architecture anchor

@main
struct HLSInterstitialDemoApp: App {
    let menuViewModel = MenuViewModel.createViewModelWithMenu

    var body: some Scene {
        WindowGroup {
            MenuView(viewModel: menuViewModel)
        }
    }
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into AVFoundation.

Ownership and state

classDiagram
    MenuItemViewModel o-- MenuItemViewModelDelegate : delegate
    MenuItemViewModel o-- PlayerState : currentPlayerState
    MenuItemViewModel o-- MenuItem : item
    MenuItemViewModel o-- Contentviewmodel : contentViewModel

Ownership evidence

HLSInterstitialDemo/HLSInterstitialDemo/Menu/ViewModels/MenuItemViewModel.swift:18 — stored dependency or nearest verified ownership anchor

@Observable
class MenuItemViewModel: Identifiable, Hashable, MenuItemLauncherViewModelDelegate {
    weak var delegate: MenuItemViewModelDelegate?
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

HLSInterstitialDemo/HLSInterstitialDemo/Helpers/AsyncPassthroughValue.swift:9 — representative execution boundary

public actor AsyncPassthroughValue<Element: Sendable>: AsyncSequence, AsyncIteratorProtocol {
    // ...
        case active
    // ...
}

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

HLSInterstitialDemo/HLSInterstitialDemo/Menu/ViewModels/MenuItemViewModel.swift:12 — representative type boundary

protocol MenuItemViewModelDelegate: AnyObject {
    func menuItemViewModelWantsToBePlayed(_ itemViewModel: MenuItemViewModel)
}

The source explicitly defines local protocol relationships: MenuItemViewModel → MenuItemLauncherViewModelDelegate, MenuSectionViewModel → MenuItemViewModelDelegate, MenuViewModel → MenuSectionViewModelDelegate.

Access control

Reference code

HLSInterstitialDemo/HLSInterstitialDemo/Helpers/AsyncPassthroughValue.swift:27 — representative boundary

    public init(_ elementType: Element.Type = Element.self) {
        state = .active
    }

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: HLSInterstitialDemoApp; Coordinator: ModalPresentationCoordinator, SharePlayCoordinator; Delegate: MenuItemLauncherViewModelDelegate, MenuItemViewModelDelegate, MenuSectionViewModelDelegate, PlayerCoordinatorDelegate; View: FillOccupancyView, IntegratedTimelinePlayerView, IntegratedTimelinePlayingUIView, IntegratedTimelinePlayingView, MenuItemLauncherView; ViewModel: ContentViewModel, MenuItemLauncherViewModel, MenuItemViewModel, MenuSectionViewModel, MenuViewModel.
• Protocols: MenuItemViewModelDelegate, MenuItemLauncherViewModelDelegate, MenuSectionViewModelDelegate.
• Methods: menuItemViewModelWantsToBePlayed, hash, dismissActiveContent, presentPlayer, menuItemLauncherViewModelWantsToBePlayed, play, menuSectionViewModel, encode.
• Files: HLSInterstitialDemo/HLSInterstitialDemo/HLSInterstitialDemoApp.swift, HLSInterstitialDemo/HLSInterstitialDemo/Menu/ViewModels/MenuItemViewModel.swift, HLSInterstitialDemo/HLSInterstitialDemo/Menu/ViewModels/MenuItemLauncherViewModel.swift, HLSInterstitialDemo/HLSInterstitialDemo/Menu/ViewModels/MenuSectionViewModel.swift, HLSInterstitialDemo/HLSInterstitialDemo/Menu/Models/Menu.swift, HLSInterstitialDemo/HLSInterstitialDemo/Menu/ViewModels/MenuViewModel.swift.

Architecture takeaways

• HLSInterstitialDemoApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, AVFoundation, GroupActivities, AVFAudio through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation