Sample CodemacOSReviewed 2026-07-21View on Apple Developer

Converting side-by-side 3D video to multiview HEVC and spatial video

At a glance

Item Summary
Purpose Create video content for visionOS by converting an existing 3D HEVC file to a multiview HEVC format, optionally adding spatial metadata to create a spatial video.
App architecture A Swift sample with the source-visible chain SideBySideToMVHEVCSideBySideConverterAVFoundation APIs.
Main patterns No named application pattern supported by the extracted structure
Project style 2 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.
Execution model Source-visible boundaries: Sendable or @Sendable, async declaration or closure, Task, DispatchQueue(label:); none alone proves a background thread.
State/event model No structured observation or publisher-scheduling marker indexed.
Key frameworks/packages Foundation, ArgumentParser, AVFoundation, CoreMedia, VideoToolbox; these are source dependencies, not architecture labels.

Project structure

Source bundle/
├── SideBySideToMVHEVC/
│   ├── SideBySideToMVHEVC.swift
│   └── Converter.swift
├── Configuration/
│   └── SampleCode.xcconfig
└── SideBySideToMVHEVC.xcodeproj/
    ├── .xcodesamplecode.plist
    └── project.pbxproj

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 4 source declaration(s).

Overall architecture

Reference code

SideBySideToMVHEVC/SideBySideToMVHEVC.swift:11 — architecture anchor

@main
struct SideBySideToMVHEVC: AsyncParsableCommand {
    // ...
    var sideBySideVideoPath: String
    // ...
}

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

Ownership evidence

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

@main
struct SideBySideToMVHEVC: AsyncParsableCommand {
    // ...
    var sideBySideVideoPath: String
    // ...
}
Owner Object or state Relationship Mutation authority
SideBySideToMVHEVC String (sideBySideVideoPath) owns value state App/module collaborators
SideBySideToMVHEVC Bool (writeSpatialMetadata) owns value state App/module collaborators
SideBySideToMVHEVC Double (baselineInMillimeters) owns value state App/module collaborators
SideBySideToMVHEVC Double (horizontalFOV) owns value state App/module collaborators

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.

Concern Source mechanism Verified placement or handoff Evidence
Transfer contract Sendable or @Sendable The source declares a sendability boundary; this alone does not synchronize mutable state. SideBySideToMVHEVC/Converter.swift:24
Suspension boundary async declaration or closure The source declares or crosses an asynchronous boundary; it does not by itself establish background execution. SideBySideToMVHEVC/Converter.swift:34
Task creation Task The source creates an unstructured task; surrounding context determines inherited actor isolation. SideBySideToMVHEVC/Converter.swift:66
Queue scheduling DispatchQueue(label:) The source constructs a dispatch queue; its label alone does not prove a thread. SideBySideToMVHEVC/Converter.swift:122

@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

SideBySideToMVHEVC/Converter.swift:24 — representative execution boundary

final class SideBySideConverter: Sendable {
    let sideBySideFrameSize: CGSize
    // ...
}

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.

Category Mechanism or module Verified role Evidence
Source import Foundation The cited file imports this module; runtime use and architectural role are not inferred. SideBySideToMVHEVC/Converter.swift:8
Source import ArgumentParser The cited file imports this module; runtime use and architectural role are not inferred. SideBySideToMVHEVC/SideBySideToMVHEVC.swift:9
Source import AVFoundation The cited file imports this module; runtime use and architectural role are not inferred. SideBySideToMVHEVC/Converter.swift:9
Source import CoreMedia The cited file imports this module; runtime use and architectural role are not inferred. SideBySideToMVHEVC/Converter.swift:10
Source import VideoToolbox The cited file imports this module; runtime use and architectural role are not inferred. SideBySideToMVHEVC/Converter.swift:11

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

SideBySideToMVHEVC/Converter.swift:24 — representative type boundary

final class SideBySideConverter: Sendable {
    let sideBySideFrameSize: CGSize
    // ...
}
Type Responsibility Depends on or conforms to
SideBySideConverter Transforms between feature representations Sendable
SideBySideToMVHEVC Represents a feature value or composable behavior AsyncParsableCommand
SpatialMetadata Represents feature data Concrete collaborators/imported frameworks
ConversionError Represents feature failure conditions Error, CustomStringConvertible

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

Access control

Symbol Access Verified effect Likely rationale
SideBySideConverter (SideBySideToMVHEVC/Converter.swift:24) implicit internal No explicit modifier means the Swift declaration is internal to the module. Inference: app-target collaboration needs no exported library surface.
SideBySideToMVHEVC (SideBySideToMVHEVC/SideBySideToMVHEVC.swift:12) implicit internal No explicit modifier means the Swift declaration is internal to the module. Inference: app-target collaboration needs no exported library surface.
SpatialMetadata (SideBySideToMVHEVC/SideBySideToMVHEVC.swift:84) implicit internal No explicit modifier means the Swift declaration is internal to the module. Inference: app-target collaboration needs no exported library surface.

Reference code

SideBySideToMVHEVC/Converter.swift:24 — representative boundary

final class SideBySideConverter: Sendable {
    let sideBySideFrameSize: CGSize
    // ...
}

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

Logic Owning type or file Placement rationale
Transforms between feature representations SideBySideConverter The source’s Converter suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
No named application pattern SideBySideToMVHEVC/SideBySideToMVHEVC.swift:11 The verified source directly composes concrete framework types; this document avoids forcing a pattern name.

Naming conventions

  • Types: Converter: SideBySideConverter.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: run, transcodeToMVHEVC, convertFrame.
  • Files: SideBySideToMVHEVC/SideBySideToMVHEVC.swift.

Architecture takeaways

  • SideBySideToMVHEVC is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches AVFoundation, ArgumentParser, CoreMedia, VideoToolbox 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

Source file Relevant symbols
SideBySideToMVHEVC/SideBySideToMVHEVC.swift Cited implementation, SideBySideToMVHEVC, SpatialMetadata, ArgumentParser, ConversionError
SideBySideToMVHEVC/Converter.swift SideBySideConverter, Sendable or @Sendable, async declaration or closure, Task, DispatchQueue(label:), Foundation, AVFoundation, CoreMedia, VideoToolbox