Enhancing your app with machine learning-based video effects

At a glance

Project structure

Source bundle/
├── VideoProcessorCommand/
│   └── VideoProcessorCommand.swift
└── VideoProcessor/
    ├── VideoProcessorApp.swift
    ├── Views/
    │   ├── VideoEffectSettingsView.swift
    │   ├── VideoPreviewView.swift
    │   ├── VideoEffectSelectionView.swift
    │   └── AVSampleBufferView.swift
    ├── AsyncIO/
    │   ├── AsyncAssetIO.swift
    │   └── AsyncIOStream.swift
    ├── VideoProcessorModel.swift
    ├── VideoProcessorView.swift
    └── Processing/
        ├── AsyncFrameProcessor.swift
        └── VideoProcessor.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 4 project/configuration file(s) and 57 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["VideoProcessor"]
    V2["VideoProcessorCommand"]
    Boundary["VideoToolbox APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

VideoProcessorCommand/VideoProcessorCommand.swift:16 — architecture anchor

@main
struct ProcessVideoEffect: AsyncParsableCommand {

    static let configuration = CommandConfiguration(
        commandName: "processVideoEffect",
        abstract: "Apply video effect to the input file, writing results to the output file.",
        subcommands: [MotionBlur.self, FrateRateConversion.self])
}

Interpretation

The branches represent separate entry-bearing project variants in the downloaded bundle, not runtime calls between those variants. Each branch is intentionally collapsed at the documented framework boundary; the detailed target-local flow remains in the cited files. Ownership is claimed only where the next section cites a stored property or assignment.

Ownership and state

classDiagram
    SampleBuffer o-- Cmsamplebuffer : cmSampleBuffer
    AsyncAssetReader o-- SampleBufferStream : inputStream
    AsyncAssetReader *-- URL : inputURL
    AsyncAssetReader *-- Dictionary : videoSettings

Ownership evidence

VideoProcessor/AsyncIO/AsyncAssetIO.swift:20 — stored dependency or nearest verified ownership anchor

struct SampleBuffer: Sendable {
    // ...
        self.cmSampleBuffer = cmSampleBuffer
    // ...
}

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

VideoProcessor/AsyncIO/AsyncAssetIO.swift:15 — representative execution boundary

struct SampleBuffer: Sendable {
    // ...
    nonisolated(unsafe) let cmSampleBuffer: CMSampleBuffer
    // ...
}

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

VideoProcessor/Processing/AsyncFrameProcessor.swift:16 — representative type boundary

protocol AsyncFrameProcessor: Actor {
    // ...
    typealias Fault = AsyncFrameProcessorFault
    // ...
}

The source explicitly defines local protocol relationships: AsyncAssetReader → AsyncFrameProcessor, AsyncAssetWriter → AsyncFrameProcessor, FrameRateConversionProcessor → AsyncFrameProcessor, LowLatencyFrameInterpolation → AsyncFrameProcessor, LowLatencySuperResolutionScaler → AsyncFrameProcessor, MotionBlurProcessor → AsyncFrameProcessor.

Access control

Reference code

VideoProcessor/AsyncIO/AsyncAssetIO.swift:53 — representative boundary

actor AsyncAssetReader: AsyncFrameProcessor {
    // ...
    private let avAsset: AVURLAsset
    // ...
}

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 VideoProcessor
    participant assetReader
    participant verifyBuffer
    participant frameProcessor
    participant assetWriter
    participant model
    participant taskGroup
    VideoProcessor->>VideoProcessor: withThrowingTaskGroup()
    VideoProcessor->>assetReader: videoTrackDimensions()
    VideoProcessor->>verifyBuffer: setInputStream()
    VideoProcessor->>frameProcessor: setInputStream()
    VideoProcessor->>assetWriter: setInputStream()
    VideoProcessor->>model: setState()
    VideoProcessor->>taskGroup: next()
    VideoProcessor->>model: setState()

Reference code

VideoProcessor/Processing/VideoProcessor.swift:165 — processVideo()

            await setOutputPreviewStream(outputPreviewStream)

            // Create `AsyncAssetWriter` to write the output `SampleBufferStream` to disk.
            let assetWriter = AsyncAssetWriter(outputURL: outputURL)
            try await assetWriter.setInputStream(frameProcessorOutputStream)

            // This creates the `taskGroup` tasks that do the actual work.
            taskGroup.addTask { try await assetReader.run() }

Naming conventions

• Types: App: VideoProcessorApp; Document: MovieDocument; Model: VideoProcessorModel; Processor: AsyncFrameProcessor, FrameRateConversionProcessor, MotionBlurProcessor, VideoProcessor; View: AVSampleBufferUIView, AVSampleBufferView, ChooseVideoEffectView, DetailView, FrameRateConversionView.
• Protocols: AsyncFrameProcessor.
• Methods: validate, run, fileWrapper, propagateAttachments, configure, progressStream, videoTrackDimensions, setInputStream.
• Files: VideoProcessor/VideoProcessorApp.swift, VideoProcessor/Views/VideoEffectSettingsView.swift, VideoProcessor/Views/VideoPreviewView.swift, VideoProcessor/VideoProcessorModel.swift, VideoProcessor/VideoProcessorView.swift, VideoProcessor/Views/VideoEffectSelectionView.swift.

Architecture takeaways

• VideoProcessorCommand is the main source-visible entry or composition anchor for this sample.
• Framework work reaches VideoToolbox, SwiftUI, AVFoundation, AppKit 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