Media
You MUST use this skill for ANY camera, photo, audio, haptic, or media playback work.
Auditors are skills here. Where this router says "Launch
some-auditoragent", invoke the matching Codex skill instead — same procedure, no Claude Code agent required.Available:
axiom-audit-camera.The ones that shell out — builds, tests, simulators, crash symbolication — need shell access to run.
Quick Reference
| Symptom / Task | Reference |
|---|---|
| Camera capture, AVCaptureSession | See skills/camera-capture.md |
Slow camera launch / deferred start (iOS 26+), ProRes recording via Pro Video Storage (OS27) | See skills/camera-capture.md Patterns 8-9 |
| Camera API (RotationCoordinator, etc.) | See skills/camera-capture-ref.md |
Lens aperture / shutter / ISO priority modes, exposure signals, continuous autofocus tracking, low-light video noise reduction, cinematic video metadata capture (OS27) | See skills/camera-capture-ref.md |
| Center Stage front camera (iPhone 17), dynamic aspect ratio, smart framing, 24/48 MP capture | See skills/camera-capture-ref.md |
| iPhone Duo front cameras (virtual front camera, inner/outer ultra-wide), camera direction vs position | See skills/camera-capture.md Pattern 6 and skills/camera-capture-ref.md (iPhone Duo Front Cameras) |
| Camera freezes, black preview, rotation | See skills/camera-capture-diag.md |
| Photo pickers, library access | See skills/photo-library.md |
PHPicker, PhotosPicker, PhotoKit API reference: asset metadata editing (keywords, rating, caption), persistent change observer, background resource upload (OS27) | See skills/photo-library-ref.md |
PhotoKit + Swift 6 strict concurrency, nonisolated observer, performChanges isolation, _dispatch_assert_queue_fail | See axiom-concurrency (skills/isolation-inheritance-diag.md) |
Audio, AVFoundation, spatial audio, async session activation, throwing AVAudioEngine APIs (OS27) | See skills/avfoundation-ref.md |
Video write/export/playback, sample-buffer engine, resumable export, Apple Log 2, iOS 27 deprecations (OS27) | See skills/avfoundation-video-ref.md |
| Audio recognition, ShazamKit | See skills/shazamkit.md |
| ShazamKit API reference | See skills/shazamkit-ref.md |
On-device music analysis (key, tempo, structure, loudness), MusicUnderstanding (OS27) | See skills/music-understanding.md |
On-device face grouping (cluster faces into people across a library), video highlights/key frames, MediaIntelligence (OS27) | See skills/media-intelligence.md |
| Haptic feedback, Core Haptics | See skills/haptics.md |
| SharePlay coordinated playback, AVDelegatingPlaybackCoordinator, custom-engine sync | See skills/shareplay-playback.md |
| SharePlay session lifecycle, activation, non-media state | Use axiom-integration (skills/shareplay.md) instead |
| Now Playing metadata, remote commands | See skills/now-playing.md |
| Animated lock-screen artwork (iOS 26+) | See skills/now-playing.md Pattern 8 |
NowPlaying framework (import NowPlaying, Swift-native MediaSession, OS27) | See skills/now-playing.md (NowPlaying Framework section) |
Cast / route media to non-AirPlay devices (Google Cast/Chromecast, DLNA) as system routes, AVSystemRouting (iOS27, likely EU-gated) | See skills/system-media-routing.md |
Screen capture / recording / streaming the screen or your own app, ScreenCaptureKit (OS27 — new on iOS/iPadOS/tvOS/visionOS 27; macOS 12.3+) | See skills/screen-capture.md |
| CarPlay HIG, app categories, design rules, entitlements | See skills/carplay-hig.md |
| CarPlay templates reference (all 12 templates, availability matrix, depth limits) | See skills/carplay-templates-ref.md |
| CarPlay navigation reference (base view, route guidance, cluster/HUD, multitouch, voice prompts, map panels + EV charging iOS 27) | See skills/carplay-navigation-ref.md |
| CarPlay Now Playing template customization + sports mode | See skills/now-playing-carplay.md |
| MusicKit Now Playing, ApplicationMusicPlayer playback, subscription/authorization | See skills/now-playing-musickit.md |
Enumerate the user's Apple Music library — MusicLibraryRequest vs MPMediaQuery, reconciling the two, playlist entries, sync, library identity, per-device Song.id, missing PlayParameters, MusicKit stops responding after a scan | See skills/music-library.md |
| DockKit motorized stands / gimbals, subject tracking, custom motor control | See skills/dockkit.md |
| Speech-to-text / transcription (SpeechAnalyzer, mic → transcript) | Invoke axiom-ai (skills/ios-ml.md) |
Decision Tree
dotdigraph media { start [label="Media task" shape=ellipse]; what [label="Which media feature?" shape=diamond]; auditor [label="camera-auditor agent" shape=box]; start -> what; what -> "skills/camera-capture.md" [label="camera capture"]; what -> "skills/photo-library.md" [label="photo pickers\n/ library"]; what -> "skills/avfoundation-ref.md" [label="audio / AVFoundation"]; what -> "skills/avfoundation-video-ref.md" [label="video write/export\n/ sample-buffer (OS27)"]; what -> "skills/shazamkit.md" [label="ShazamKit\n/ audio recognition"]; what -> "skills/music-understanding.md" [label="music analysis\n(key/tempo/structure)"]; what -> "skills/media-intelligence.md" [label="face grouping /\nvideo highlights (OS27)"]; what -> "skills/haptics.md" [label="haptic feedback"]; what -> "skills/now-playing.md" [label="Now Playing\n/ remote commands"]; what -> "skills/music-library.md" [label="enumerate Apple Music\nlibrary / identity"]; what -> "skills/system-media-routing.md" [label="cast to non-AirPlay\n(Chromecast/DLNA, iOS27)"]; what -> "skills/screen-capture.md" [label="screen capture /\nrecording (OS27)"]; what -> "skills/carplay-hig.md" [label="CarPlay app design\n/ categories / entitlements"]; what -> "skills/dockkit.md" [label="DockKit stands\n/ gimbals / tracking"]; what -> auditor [label="camera code audit"]; }
- Camera capture? →
skills/camera-capture.md(patterns),skills/camera-capture-ref.md(API),skills/camera-capture-diag.md(debugging) - Photo pickers / library? →
skills/photo-library.md,skills/photo-library-ref.md - Audio / AVFoundation (audio)? →
skills/avfoundation-ref.md; video write/export/playback, sample-buffer engine, resumable export, iOS 27 deprecations? →skills/avfoundation-video-ref.md(OS27) - ShazamKit / audio recognition? →
skills/shazamkit.md,skills/shazamkit-ref.md - On-device music analysis (key, tempo, structure, pace, instruments, loudness)? →
skills/music-understanding.md(OS27) - On-device face grouping (cluster faces into people across a library) or video highlights / key-frame detection? →
skills/media-intelligence.md(OS27) - Haptics? →
skills/haptics.md - Now Playing / remote commands? →
skills/now-playing.md,skills/now-playing-carplay.md,skills/now-playing-musickit.md - Reading the user's Apple Music library (enumerate songs/playlists, library identity, sync)? →
skills/music-library.md— a different problem from playback; read it before any library walk - Cast / route media to non-AirPlay devices (Google Cast/Chromecast, DLNA) as system routes? →
skills/system-media-routing.md(iOS27, likely EU-gated) - Screen capture / recording / streaming the screen or your own app (ScreenCaptureKit)? →
skills/screen-capture.md(OS27— new on iOS/iPadOS/tvOS/visionOS 27) - CarPlay app design, category selection, entitlement request? →
skills/carplay-hig.md(start here for any CarPlay work) - DockKit motorized stands / gimbals, subject tracking, custom motor control? →
skills/dockkit.md - Want camera code audit? →
axiom-audit-camera(detects deprecated APIs and architectural gaps: missing interruption handlers, runtime-error recovery, audio session deactivation, permission-denied UX, RotationCoordinator on iOS 17+; scores RELIABLE / FRAGILE / BROKEN)
Cross-Domain Routing
Camera + permissions (camera access denied, Info.plist missing):
- Camera code → stay here (camera-capture)
- Privacy manifest / Info.plist → invoke axiom-integration (privacy-ux reference)
- Build/entitlement errors → invoke axiom-build
ShazamKit + microphone permissions:
- Microphone NSMicrophoneUsageDescription → invoke axiom-integration (privacy-ux reference)
- ShazamKit API and matching → stay here (shazamkit)
Now Playing + background audio:
- Now Playing metadata/controls → stay here (now-playing)
- Background audio mode / BGTaskScheduler → invoke axiom-integration (background-processing reference)
Speech-to-text + audio capture (transcribing mic or asset audio):
SpeechAnalyzer/SpeechTranscriber, the ~2-simultaneous-analyzer cap, theOS27input providers → invoke axiom-ai (skills/ios-ml.md)- Audio session category/mode,
AVCaptureSessionwiring → stay here (avfoundation-ref, camera-capture) - The trap:
CaptureInputSequenceProvider.providerWithSession(...)(OS27) automatically reconfigures your app's defaultAVAudioSession. If this suite's audio-session setup "randomly breaks" after transcription is added, that's the cause — useprovider(from:in:)and add itscaptureAudioDataOutputto your own session.
Apple Music library + playback + persistence:
- Enumerating the library, library identity,
PlayParametersavailability, Sync Library hazards → stay here (music-library) - Queuing and playing what you found, Now Playing publishing → stay here (now-playing-musickit)
- Storing library rows in your own database (which column is the durable key, migrations for a re-key) → invoke axiom-data — but take the identity rules from music-library first;
persistentIDis not a durable key MusicAuthorizationprompt copy / privacy manifest → invoke axiom-integration (privacy-ux reference)
Photo library + privacy:
- Photo picker (PHPicker, PhotosPicker) → stay here (photo-library) — no permissions needed
- Full PHPhotoLibrary access → stay here (photo-library-ref) — limited access model
- Privacy manifest for photo usage → invoke axiom-integration (privacy-ux reference)
DockKit + camera / custom inference:
- DockKit stand control, framing, motor, tracking states → stay here (dockkit)
- Underlying AVCaptureSession setup → stay here (camera-capture)
- Custom Vision / Core ML inference feeding observations → invoke axiom-vision
- Camera permission (NSCameraUsageDescription) → invoke axiom-integration (privacy-ux reference)
MediaIntelligence + Vision (faces, image analysis):
- Group faces into people across a library, video highlights / key frames → stay here (media-intelligence) — clustering identities + on-device video moment detection
- Detect where a face is in one image (bounding box, landmarks), OCR, segmentation → invoke axiom-vision — per-image detection, a different problem
- System Photos "People" album → that album is system-owned (PhotoKit); MediaIntelligence builds your own index over assets you manage → stay here (photo-library for the asset access)
Anti-Rationalization
| Thought | Reality |
|---|---|
| "Camera capture is just AVCaptureSession setup" | Camera has interruption handlers, rotation, and threading requirements. |
| "Camera launch is fast enough if I startRunning() early" | Output initialization dominates launch; iOS 26 deferred start halves time-to-preview. |
| "I'll add haptics with a simple API call" | Haptic design has patterns for each interaction type matching HIG. |
| "ShazamKit is just SHSession + a delegate" | iOS 17+ has SHManagedSession which eliminates all AVAudioEngine boilerplate. |
| "Now Playing info is just setting metadata" | Remote commands, artwork handling, and state sync have 15+ gotchas. |
| "I'll use UIImagePickerController for photos" | PHPicker/PhotosPicker are the modern API — no permissions required. |
| "MediaPlayer reports fewer playlist members than MusicKit, so sync is incomplete" | The gap is structural, not a sync signal: it tracks the entries with no local representation — exact on all five playlists inspected, off by one library-wide. A shipped guard built on this premise silently skipped 9 of 15 playlists forever. Read skills/music-library.md. |
| "Reading the music library is just a MusicLibraryRequest" | Reading one MusicKit property across a large library leaves every later MusicKit request unresumed for the rest of the run, with no error thrown. Pool starvation is a symptom, not the mechanism — a plain Thread, which never touches the pool, loses MusicKit identically. Batching the request is ~100x slower, not safer. |
"Song.id is a stable key I can store" | Its format differs per device for the same library (i.… on one, bare numeric on another). Never parse it, never use it as a cross-device key. |
| "DockKit is just pairing a stand" | Custom control needs system tracking disabled, handles inverted dock states, and two different coordinate origins. |
| "Grouping faces is just Vision face detection" | Vision detects faces in one image; MediaIntelligence clusters them into persistent people (entities) across a whole library, with its own working directory and state. |
| "Casting to Chromecast means bundling the Google Cast SDK" | On iOS 27, AVSystemRouting exposes non-AirPlay routes as system routes — you adopt one Apple API (observe events, start a session, drive playbackControl) instead of a per-vendor SDK. Likely EU-gated — gate and keep a fallback. |
| "I'll sync SharePlay playback by broadcasting the current time over the messenger" | The messenger has no clock. AVDelegatingPlaybackCoordinatorPlayCommand.hostClockTime gives you an absolute CMClockGetHostTimeClock() start time; hand-rolling reinvents startup barriers, seek ordering, stalls, and interruptions badly. |
| "The playback coordinator handles interruptions for me" | Only AVPlayerPlaybackCoordinator does. AVDelegatingPlaybackCoordinator adds no automatic suspensions — a custom engine begins and ends every one, and a suspension never ended hangs the whole group. |
| "ScreenCaptureKit on iPad works like the Mac (enumerate displays/windows)" | On iOS/iPadOS SCShareableContent and all SCContentFilter initializers are macOS-only — you get a filter ONLY from the system SCContentSharingPicker. New on iOS/iPadOS/tvOS/visionOS 27. Also not ImageRenderer (that snapshots your own SwiftUI view). |
Example Invocations
User: "How do I set up a camera preview?"
→ Read: skills/camera-capture.md
User: "My camera app takes a second before preview appears"
→ Read: skills/camera-capture.md (Pattern 8, deferred start)
User: "Support the Center Stage front camera" / "Capture 48MP photos"
→ Read: skills/camera-capture-ref.md
User: "How do I switch cameras on iPhone Duo?" / "Choose a camera by direction instead of position"
→ Read: skills/camera-capture.md (Pattern 6) and skills/camera-capture-ref.md (iPhone Duo Front Cameras)
User: "Camera freezes when I get a phone call"
→ Read: skills/camera-capture-diag.md
User: "How do I let users pick photos in SwiftUI?"
→ Read: skills/photo-library.md
User: "Implement haptic feedback for button taps"
→ Read: skills/haptics.md
User: "Now Playing info doesn't appear on Lock Screen"
→ Read: skills/now-playing.md
User: "How do I identify songs with ShazamKit?"
→ Read: skills/shazamkit.md
User: "How do I detect a song's tempo / key / beat grid on-device?" / "Analyze audio loudness or structure"
→ Read: skills/music-understanding.md
User: "Group faces into people across my photo library" / "cluster faces on-device" / "find highlights or a thumbnail frame in a video"
→ Read: skills/media-intelligence.md
User: "Cast to Chromecast / Google Cast without the Cast SDK" / "support non-AirPlay casting" / "route media to a DLNA device as a system route"
→ Read: skills/system-media-routing.md
User: "Record / stream the iPad screen" / "ScreenCaptureKit on iOS" / "screen recording in my app" / "capture just my app's content"
→ Read: skills/screen-capture.md
User: "List every song in the user's Apple Music library" / "enumerate their playlists" / "MPMediaQuery vs MusicKit" / "sync Apple Music playlists" / "MediaPlayer and MusicKit report different playlist counts" / "my MusicKit requests stop responding after a library scan" / "store a stable id for each song across devices" / "playlists went empty after the user turned on Sync Library"
→ Read: skills/music-library.md
User: "Track a subject with a motorized stand" / "Control a DockKit gimbal"
→ Read: skills/dockkit.md
User: "Check my camera code for issues"
→ Launch: camera-auditor agent
