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 SideBySideToMVHEVC → SideBySideConverter → AVFoundation 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
flowchart LR
N1["SideBySideToMVHEVC"]
N2["SideBySideConverter"]
N3["AVFoundation APIs"]
N1 --> N2
N2 --> N3
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
classDiagram
SideBySideToMVHEVC *-- String : sideBySideVideoPath
SideBySideToMVHEVC *-- Bool : writeSpatialMetadata
SideBySideToMVHEVC *-- Double : baselineInMillimeters
SideBySideToMVHEVC *-- Double : horizontalFOV
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
SideBySideToMVHEVCis 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 |