Processing Apple Immersive Video with foveation

At a glance

Project structure

Source bundle/
├── ImmersiveMediaSupport-Foveation/
│   ├── ImmersiveMediaSupport-Foveation/
│   │   ├── FoveateAIV.swift
│   │   ├── AIMEProcessor.swift
│   │   ├── FoveationEngine.swift
│   │   ├── MetalProcessor.swift
│   │   ├── VideoProcessor.swift
│   │   ├── UVSample.metal
│   │   ├── Types/
│   │   │   ├── FoveationConfig.swift
│   │   │   └── RuntimeError.swift
│   │   └── AVVideoCodecTypeExtension.swift
│   └── ImmersiveMediaSupport-Foveation.xcodeproj/
│       ├── .xcodesamplecode.plist
│       └── project.pbxproj
└── Configuration/
    └── SampleCode.xcconfig

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Metal, Swift.
• The verified tree contains 3 project/configuration file(s) and 9 source declaration(s).

Overall architecture

flowchart LR
    N1["FoveateAIV"]
    N2["FoveationEngine"]
    N3["ImmersiveMediaSupport APIs"]
    N1 --> N2
    N2 --> N3

Reference code

ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/FoveateAIV.swift:12 — architecture anchor

@main
struct FoveateAIV: AsyncParsableCommand {
    static let configuration = CommandConfiguration(
        abstract: """
        Apply variable rasterization rate (VRR) style foveation to Apple Immersive Video (AIV) file
        and Apple Immersive Media Embedded (AIME) metadata file.
        """,
        discussion: """
        This tool processes AIV file (`.mov` file) and AIME metadata file (`.aime` file)
        by applying VRR style foveation that reduces visual quality in peripheral areas
        while maintaining high quality in the center of focus.
        """
    )
    // ...
}

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 Immersive Media Support.

Ownership and state

classDiagram
    FoveateAIV *-- CommandConfiguration : configuration
    FoveateAIV *-- String : inputVideoFile
    FoveateAIV *-- String : inputAIMEFile
    FoveateAIV *-- String : outputDirectory

Ownership evidence

ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/FoveateAIV.swift:14 — stored dependency or nearest verified ownership anchor

@main
struct FoveateAIV: AsyncParsableCommand {
    // ...
}

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

ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/AIMEProcessor.swift:24 — representative execution boundary

    init(
        // ...
    ) async throws {
        // ...
    }

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

ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/AIMEProcessor.swift:12 — representative type boundary

final class AIMEProcessor {
    // ...
    private let foveationConfig: FoveationConfig
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/AIMEProcessor.swift:14 — representative boundary

final class AIMEProcessor {
    // ...
    private let foveationConfig: FoveationConfig
    // ...
}

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 FoveateAIV
    participant VideoProcessor
    participant videoProcessor
    participant AIMEProcessor
    participant aimeProcessor
    FoveateAIV->>VideoProcessor: VideoProcessor()
    FoveateAIV->>videoProcessor: process()
    FoveateAIV->>AIMEProcessor: AIMEProcessor()
    FoveateAIV->>aimeProcessor: process()

Reference code

ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/FoveateAIV.swift:92 — run()

@main
struct FoveateAIV: AsyncParsableCommand {
    // ...
        let aimeProcessor = try await AIMEProcessor(
            inputAIMEURL: inputAIMEURL,
            outputAIMEURL: outputAIMEURL,
            foveationConfig: foveationConfig
        )
    // ...
}

Naming conventions

• Types: Engine: FoveationEngine; Processor: AIMEProcessor, MetalProcessor, VideoProcessor.
• Protocols: no local protocol declaration in the scanned source.
• Methods: run, validateParameters, validateInputs, validateOutputs, process, foveateMesh, generateMesh, createBuffers.
• Files: ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/FoveateAIV.swift, ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/AIMEProcessor.swift, ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/FoveationEngine.swift, ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/MetalProcessor.swift, ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/VideoProcessor.swift, ImmersiveMediaSupport-Foveation/ImmersiveMediaSupport-Foveation/Types/FoveationConfig.swift.

Architecture takeaways

• FoveateAIV is the main source-visible entry or composition anchor for this sample.
• Framework work reaches AVFoundation, VideoToolbox, ArgumentParser, ImmersiveMediaSupport 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.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation