direct-stereo-audio

name	direct-stereo-audio
description	Guardrail keeping spatialAudioEnabled = false (Direct Stereo, HRTF bypass) as the default in LowLatencyAudioPlayer.swift — the PS5 Tempest Engine already outputs binaural audio. Load before editing LowLatencyAudioPlayer.swift or any audio output/spatialization code. Severity high — flipping the default causes metallic double-spatialization artifacts.
user-invocable	false

Direct Stereo Audio (HRTF Bypass) Is The Default

Status: enforced | Severity: high — audio regression Applies to: VisionRemotePS5/Streaming/LowLatencyAudioPlayer.swift Evidence: LowLatencyAudioPlayer.swift:50-57 (the flag and rationale), :325-339 (Direct Stereo branch), :341-350 (HRTF + fallback branch), TODO.md:58-72 (Phase 2.1/2.2 — Direct Stereo / N/A spatialization)

Reality

The PS5's Tempest 3D Audio Engine produces binaural audio internally. Re-applying HRTF on the visionOS side via AVAudioEnvironmentNode causes double-spatialization, which sounds like:

• Metallic ringing on transients.
• Phantom positional shift outside the intended sound field.
• 5–10 dB peak attenuation on stereo-panned effects.

Fix (LowLatencyAudioPlayer.swift:50-57):

// MARK: - v10.1 Direct Stereo Mode (Bypass HRTF)
/// v10.1: Enable spatial audio (HRTF processing)
/// Set to FALSE for "Direct Stereo" when PS5 Tempest Engine already provides binaural audio.
/// This prevents double-processing that causes metallic/echo artifacts.
/// Default: false for optimal PS5 Remote Play audio quality.
var spatialAudioEnabled: Bool = false

The Direct Stereo branch (LowLatencyAudioPlayer.swift:325-339) connects L/R sources directly to mainMixerNode with pan = -1.0 / pan = +1.0. The HRTF branch is preserved for users who explicitly opt in.

Hallucination vector

An LLM will:

• "Restore spatial audio" by flipping the default to true because "this is visionOS, spatial audio is the whole point".
• Remove the Direct Stereo branch entirely as "dead code".
• Remove the fallback branch at :344-349 because the early return at :338 "makes it unreachable" (it isn't — it's reachable when spatialAudioEnabled = true AND the env node fails to allocate).
• Replace engine.connect(leftSource, to: engine.mainMixerNode, format: format) with a PHASE-engine spatializer because PHASE is "more modern".

Hard rules

You MUST NEVER:

1. Change the default value of spatialAudioEnabled from false to true in LowLatencyAudioPlayer.swift:57.
2. Delete the Direct Stereo branch (the if !spatialAudioEnabled { ... return } block at :327-339).
3. Delete the fallback path at :344-349 (the guard let envNode = environmentNode else { ... }).
4. Replace AVAudioEngine with PHASEEngine. The lock-free SPSC ring buffer (AudioRingBuffer.swift) feeds AVAudioSourceNode via render block — PHASE has different threading guarantees.
5. Add a PHASE import to this file or to AudioDecoder.swift.
6. Reorder the connection sequence: it must be leftSource → mixer, rightSource → mixer, then pan assignments. The pan must be set AFTER the connect (otherwise format negotiation overwrites it on some iOS versions; same applies on visionOS).
7. Remove the DebugLog.info("LowLatencyAudio", "🎧 Direct Stereo enabled (HRTF bypassed, Tempest preserved)") log line — it is the user-facing confirmation of mode in the console.

You MUST:

• If the user explicitly asks to enable spatial audio, change the call site that sets spatialAudioEnabled (e.g., a SettingsView toggle), NOT the default in LowLatencyAudioPlayer.swift.
• If you add a new audio output mode, add it as a new value of an enum (e.g., enum AudioOutputMode { case directStereo, hrtf, custom }) rather than another Bool flag.
• Preserve the comment block at :50-56 verbatim as the rationale anchor.

Before/After

// BEFORE (LLM "modernization" — REJECT):
var spatialAudioEnabled: Bool = true  // Spatial audio is the visionOS default
// ... later ...
private func setupStereoEmitterArray() {
    // [Direct Stereo branch removed as "unused"]
    environmentNode = AVAudioEnvironmentNode()
    // ...
}

// AFTER (the only correct form):
/// Default: false for optimal PS5 Remote Play audio quality.
var spatialAudioEnabled: Bool = false
// ... later ...
if !spatialAudioEnabled {
    engine.connect(leftSource, to: engine.mainMixerNode, format: format)
    engine.connect(rightSource, to: engine.mainMixerNode, format: format)
    leftSource.pan = -1.0
    rightSource.pan = +1.0
    DebugLog.info("LowLatencyAudio", "🎧 Direct Stereo enabled (HRTF bypassed, Tempest preserved)")
    return
}
// HRTF path with fallback follows...