---
gsd_state_version: 1.0
milestone: v1.0
milestone_name: milestone
status: verifying
stopped_at: "Completed 02-audio-engine/02-03-PLAN.md (architecture redesign: browser audio + librosa)"
last_updated: "2026-04-06T15:40:50.951Z"
last_activity: 2026-04-06
progress:
  total_phases: 7
  completed_phases: 2
  total_plans: 7
  completed_plans: 7
  percent: 0
---

# Project State

## Project Reference

See: .planning/PROJECT.md (updated 2026-04-05)

**Core value:** Load a song, build a synchronized light show, play it back live — with precise control over every effect on every device.
**Current focus:** Phase 02 — audio-engine

## Current Position

Phase: 02 (audio-engine) — EXECUTING
Plan: 3 of 3
Status: Phase complete — ready for verification
Last activity: 2026-04-06

Progress: [░░░░░░░░░░] 0%

## Performance Metrics

**Velocity:**

- Total plans completed: 0
- Average duration: —
- Total execution time: 0 hours

**By Phase:**

| Phase | Plans | Total | Avg/Plan |
|-------|-------|-------|----------|
| - | - | - | - |

**Recent Trend:**

- Last 5 plans: —
- Trend: —

*Updated after each plan completion*
| Phase 01-foundation P01 | 4 | 2 tasks | 23 files |
| Phase 01-foundation P03 | 6 | 1 tasks | 9 files |
| Phase 01 P04 | 2 | 2 tasks | 3 files |
| Phase 02-audio-engine P01 | 525603 | 2 tasks | 5 files |
| Phase 02-audio-engine P02 | 8 | 2 tasks | 3 files |
| Phase 02-audio-engine P03 | 8min | 2 tasks | 5 files |
| Phase 02-audio-engine P03 | 4 | 9 tasks | 8 files |

## Accumulated Context

### Decisions

Decisions are logged in PROJECT.md Key Decisions table.
Recent decisions affecting current work:

- Init: Web UI over TUI — richer DAW interactions while keeping terminal aesthetic via CSS
- Init: python-mpv-jsonipc preferred over ctypes binding — no libmpv.dll dependency on Windows
- Init: Firmware deferred to Phase 7 — protocol must be validated against simulator first
- Init: undo/redo built in Phase 4 — retrofitting command pattern is expensive
- [Phase 01-foundation]: Module-level state in main.py for registry/show_store — acceptable for Phase 1, Phase 2 migrates to Depends()
- [Phase 01-foundation]: StaticFiles mounted last in create_app() — prevents catch-all interception of /api/* routes
- [Phase 01-foundation]: encode_animation_cmd stubs return b'' — Phase 3 implements real UDP animation command encoding
- [Phase 01-foundation]: redirect_slashes=False on FastAPI — StaticFiles at root intercepted API redirects
- [Phase 01-foundation]: API collection routes use empty-string paths ('') not '/' — canonical /api/devices without redirect
- [Phase 01]: window.removeDevice export required for ES module onclick compatibility — functions in type=module scripts are not global
- [Phase 01]: CSS accent variable canonical naming: --accent is source of truth, aliases are text-accent and border-bright
- [Phase 02-audio-engine]: MPV_AO env var controls audio output — null default for Docker server mode, overridable for local dev
- [Phase 02-audio-engine]: 10Hz polling via time.sleep(0.1) over observe_property — observe_property fires per audio frame overwhelming asyncio
- [Phase 02-audio-engine]: apply_timer_fix() as Linux no-op — timeBeginPeriod is Windows-only; INF-03 satisfied as platform-guarded stub
- [Phase 02-audio-engine]: broadcast_loop accepts get_engine callable instead of direct import — avoids ws.py/main.py circular import
- [Phase 02-audio-engine]: asyncio.to_thread for engine.load in REST endpoint — python-mpv-jsonipc load is synchronous, must not block event loop
- [Phase 02-audio-engine]: AUD-02 (YouTube URL loading) deferred to Phase 6 — noted in docstring, not implemented in audio.py
- [Phase 02-audio-engine]: ffmpeg subprocess pipe for MP3 waveform extraction (libsndfile/soundfile does not support MP3 natively)
- [Phase 02-audio-engine]: Transport state driven by WebSocket tick — no frontend polling
- [Phase 02-audio-engine]: Browser plays audio via HTML5 audio element — eliminates python-mpv, Docker libmpv dependency, and server-side position polling
- [Phase 02-audio-engine]: librosa.beat.beat_track for beat detection — tempo + beat grid in one call, cached in app.state.beats by filepath

### Pending Todos

None yet.

### Blockers/Concerns

- Phase 2: python-mpv-jsonipc latency on Windows 11 under load is unbenchmarked — validate with timing harness in 02-01
- Phase 4: librosa MP3 loading path on Windows needs explicit validation (soundfile falls back to audioread which requires FFmpeg on PATH)
- Phase 6: AI sync approach (LLM-assisted) has no reference implementation — treat as spike, not commitment

## Session Continuity

Last session: 2026-04-06T15:40:34.296Z
Stopped at: Completed 02-audio-engine/02-03-PLAN.md (architecture redesign: browser audio + librosa)
Resume file: None

Next action: `/gsd:plan-phase 1`