Using AVFoundation to play and persist HTTP live streams

At a glance

Project structure

Source bundle/
├── HLSCatalog/
│   ├── AppDelegate.swift
│   ├── Managers/
│   │   ├── AssetPlaybackManager.swift
│   │   ├── AssetListManager.swift
│   │   ├── AssetPersistenceManager.swift
│   │   └── StreamListManager.swift
│   ├── AssetListTableViewController.swift
│   ├── Model/
│   │   ├── Asset.swift
│   │   └── Stream.swift
│   ├── AssetListTableViewCell.swift
│   └── PerfMeasurements.swift
├── Configuration/
│   └── SampleCode.xcconfig
└── HLSCatalog.xcodeproj/
    └── .xcodesamplecode.plist

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 7 project/configuration file(s) and 14 source declaration(s).

Overall architecture

flowchart LR
    N1["AppDelegate"]
    N2["AssetListTableViewController"]
    N3["AssetListManager"]
    N4["AVFoundation APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

HLSCatalog/AppDelegate.swift:12 — architecture anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication,
                     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil) -> Bool {
        // Restore the state of the application and any running downloads.
        AssetPersistenceManager.sharedManager.restorePersistenceManager()

        return true
    }
}

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
    AppDelegate o-- UIWindow : window
    AssetPlaybackManager *-- Logger : logger
    AssetPlaybackManager *-- AssetPlaybackManager : sharedManager
    AssetPlaybackManager o-- AssetPlaybackDelegate : delegate

Ownership evidence

HLSCatalog/AppDelegate.swift:15 — stored dependency or nearest verified ownership anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    // ...
    var window: UIWindow?
    // ...
}

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

HLSCatalog/AssetListTableViewCell.swift:70 — representative execution boundary

        DispatchQueue.main.async {
            // ...
            case .downloading:
            // ...
        }

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

HLSCatalog/Managers/AssetPlaybackManager.swift:166 — representative type boundary

protocol AssetPlaybackDelegate: AnyObject {
    // ...
    func streamPlaybackManager(_ streamPlaybackManager: AssetPlaybackManager, playerReadyToPlay player: AVPlayer)
    // ...
}

The source explicitly defines local protocol relationships: AssetListTableViewController → AssetListTableViewCellDelegate, AssetListTableViewController → AssetPlaybackDelegate.

Access control

Reference code

HLSCatalog/AssetListTableViewController.swift:17 — representative boundary

private let logger = Logger(subsystem: "com.example.apple-samplecode.HLSCatalog", category: "AssetListTableViewController")

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: Controller: AssetListTableViewController; Delegate: AppDelegate, AssetListTableViewCellDelegate, AssetPlaybackDelegate; Manager: AssetListManager, AssetPersistenceManager, AssetPlaybackManager, StreamListManager.
• Protocols: AssetPlaybackDelegate, AssetListTableViewCellDelegate.
• Methods: application, resetPlayer, setAssetForPlayback, handleTimebaseRateChanged, handlePlaybackStalled, streamPlaybackManager, viewDidLoad, viewWillAppear.
• Files: HLSCatalog/AppDelegate.swift, HLSCatalog/Managers/AssetPlaybackManager.swift, HLSCatalog/AssetListTableViewController.swift, HLSCatalog/Managers/AssetListManager.swift, HLSCatalog/Managers/AssetPersistenceManager.swift, HLSCatalog/Managers/StreamListManager.swift.

Architecture takeaways

• AppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches AVFoundation, UIKit, AVKit 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