Capturing Cinematic video

At a glance

Project structure

Source bundle/
└── CinematicCaptureSample/
    ├── CinematicCaptureSampleApp.swift
    ├── Model/
    │   └── DataTypes.swift
    ├── CaptureService.swift
    ├── Views/
    │   ├── FocusOverlayView.swift
    │   ├── Controls/
    │   │   └── SimulatedApertureView.swift
    │   ├── Overlays/
    │   │   ├── RecordingTimeView.swift
    │   │   └── StatusOverlayView.swift
    │   └── Toolbars/
    │       └── MainToolbar/
    │           └── CaptureButton.swift
    ├── CameraModel.swift
    ├── CameraView.swift
    ├── Capture/
    │   └── SPCObserver.swift
    └── Preview Content/
        └── PreviewCameraModel.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 3 project/configuration file(s) and 36 source declaration(s).

Overall architecture

flowchart LR
    N1["CinematicCaptureSampleApp"]
    N2["CameraView"]
    N3["CinematicMetadataManager"]
    N4["CaptureService"]
    N5["AVFoundation APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

CinematicCaptureSample/CinematicCaptureSampleApp.swift:10 — architecture anchor

@main
struct CinematicCaptureSampleApp: App {

    @State private var camera = CameraModel()

    var body: some Scene {
        WindowGroup {
            CameraView(camera: camera)
                .statusBarHidden(true)
                .task {
                    // Start the capture pipeline.
                    await camera.start()
                }
        }
    }
}

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
    CinematicCaptureSampleApp *-- CameraModel : camera
    CinematicCaptureSampleApp *-- Logger : logger
    Movie *-- URL : url
    CinematicMetadataManager *-- Array : cinematicFocusMetadata

Ownership evidence

CinematicCaptureSample/CinematicCaptureSampleApp.swift:13 — stored dependency or nearest verified ownership anchor

@main
struct CinematicCaptureSampleApp: App {
    // ...
    @State private var camera = CameraModel()
    // ...
}

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

CinematicCaptureSample/CameraModel.swift:21 — representative execution boundary

@MainActor
@Observable
final class CameraModel: Camera {
    // ...
    let preview: CALayer = AVSampleBufferDisplayLayer()
    // ...
}

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

CinematicCaptureSample/Model/DataTypes.swift:77 — representative type boundary

protocol OutputService {
    associatedtype Output: AVCaptureOutput
    var output: Output { get }
    var captureActivity: CaptureActivity { get }
    func updateConfiguration(for device: AVCaptureDevice)
    func setVideoRotationAngle(_ angle: CGFloat)
}

The source explicitly defines local protocol relationships: CameraModel → Camera, MovieCapture → OutputService, PreviewCameraModel → Camera.

Access control

Reference code

CinematicCaptureSample/CameraModel.swift:33 — representative boundary

@MainActor
@Observable
final class CameraModel: Camera {
    // ...
    private(set) var status = CameraStatus.unknown
    // ...
}

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

Main application flow

sequenceDiagram
    participant Output as Metadata output
    participant Service as CaptureService
    participant Store as CinematicMetadataManager
    participant Overlay as FocusOverlayView
    actor User
    Output->>Service: metadataOutput(objects)
    Service->>Store: replace normalized focus metadata
    Store-->>Overlay: observable update
    User->>Overlay: tap or long press
    Overlay->>Service: focus command through CameraModel
    Service->>Service: configure device focus

Reference code

CinematicCaptureSample/CaptureService.swift:498 — metadataOutput

    nonisolated func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        assumeIsolated { isolatedSelf in

            isolatedSelf.metadataObjectsCache = metadataObjects

            var cinematicFocusMetadataObjects = [CinematicFocusMetadata]()
            for metadataObject in metadataObjects {

                // Don't draw bodies in the preview as otherwise the preview gets too busy.
                if metadataObject.type == .catBody || metadataObject.type == .dogBody || metadataObject.type == .humanBody {
                    continue
                }

                let boundsInOutputCoordinates = isolatedSelf.videoOutput.outputRectConverted(fromMetadataOutputRect: metadataObject.bounds)
                let fullFrameInOutputCoordinates = isolatedSelf.videoOutput.outputRectConverted(fromMetadataOutputRect: CGRect(x: 0, y: 0, width: 1, height: 1))
                let layerBoundsNormalized = CGRect(x: boundsInOutputCoordinates.origin.x / fullFrameInOutputCoordinates.width,
                                                   y: boundsInOutputCoordinates.origin.y / fullFrameInOutputCoordinates.height,
                                                   width: boundsInOutputCoordinates.size.width / fullFrameInOutputCoordinates.width,
                                                   height: boundsInOutputCoordinates.size.height / fullFrameInOutputCoordinates.size.height)

                let cinematicFocusMetadata = CinematicFocusMetadata(metadataObject: metadataObject, layerBoundsNormalized: layerBoundsNormalized)
                cinematicFocusMetadataObjects.append(cinematicFocusMetadata)
            }

            isolatedSelf.metadataManager.cinematicFocusMetadata = cinematicFocusMetadataObjects
        }
    }

Naming conventions

• Types: App: CinematicCaptureSampleApp; Delegate: MovieCaptureDelegate; Manager: CinematicMetadataManager; Model: CameraModel, PreviewCameraModel; Observer: SystemPreferredCameraObserver; Service: CaptureService, OutputService; View: CameraView, FocusOverlayView, PreviewView, RecordingTimeView, SimulatedApertureView.
• Protocols: OutputService, Camera.
• Methods: updateConfiguration, setVideoRotationAngle, start, setUpSession, metadataVDOSetup, updateVDORotation, addInput, addOutput.
• Files: CinematicCaptureSample/CinematicCaptureSampleApp.swift, CinematicCaptureSample/CaptureService.swift, CinematicCaptureSample/Views/FocusOverlayView.swift, CinematicCaptureSample/CameraModel.swift, CinematicCaptureSample/CameraView.swift, CinematicCaptureSample/Preview Content/PreviewCameraModel.swift.

Architecture takeaways

• CinematicCaptureSampleApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, AVFoundation, CoreMedia, PhotosUI 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