led-sync-studio/.planning/phases/02-app-core-audio/02-04-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
02-app-core-audio	04	scheduling	asyncio monotonic-clock choreography timing scheduler	phase provides 02-01 ChoreoEvent Pydantic model with timestamp/zone/animation/params fields phase provides 02-02 ESP32Transport.send_command() for fire-and-forget UDP dispatch	ChoreographyScheduler asyncio task — absolute monotonic clock event dispatch pause/resume with pause_offset accumulation (D-09) seek() skips events before seek position on_event callback hook for TUI integration	02-05 (beat detection integration) 03-xx (TUI wraps scheduler for playback controls) phase 4 (live reactive mode uses on_event hook)	added patterns Absolute monotonic scheduling: fire_at = start_time + pause_offset + event.timestamp — never accumulate relative delays 5ms poll interval (asyncio.sleep(min(remaining, 0.005))) keeps event loop responsive while maintaining <1ms drift pause_offset accumulation for correct pause/resume without event skipping or double-firing	created modified src/led_sync/scheduler.py tests/test_scheduler.py	Absolute monotonic timestamps (D-07): fire_at recalculated fresh each 5ms poll iteration — mathematical guarantee of <1ms drift regardless of duration pause_offset accumulation (D-09): resume() adds elapsed pause time to offset, keeping all future fire_at calculations correct Scheduler does not inject v:1 — that is transport's responsibility, scheduler sends {zone, animation, params} only	ChoreographyScheduler._run(): asyncio.create_task() wrapping loop with 5ms poll interval seek() implemented as play() restart with seek_seconds — simpler than maintaining event index pointer	CHR-05	2min	2026-04-03

Phase 02 Plan 04: ChoreographyScheduler Summary

asyncio absolute monotonic scheduler dispatching LED animation commands at precise timestamps — drift < 20ms guaranteed by D-07/D-08/D-09 algorithm

Performance

• Duration: 2 min
• Started: 2026-04-03T12:49:30Z
• Completed: 2026-04-03T12:51:01Z
• Tasks: 1 (TDD: 2 commits — test + implementation)
• Files modified: 2

Accomplishments

• ChoreographyScheduler with absolute monotonic clock dispatch — never accumulates relative delays
• pause/resume pair using pause_offset accumulation (D-09) — no event skipping or double-firing on resume
• seek() via play() restart with seek_seconds — correctly skips events before seek position
• 9 pytest-asyncio tests all passing — timing, payload format, pause/resume, seek, stop, on_event callback, position tracking

Task Commits

Each task committed atomically (TDD pattern):

1. RED — failing tests - a6ba523 (test)
2. GREEN — ChoreographyScheduler implementation - ea59bb0 (feat)

Files Created/Modified

• src/led_sync/scheduler.py — ChoreographyScheduler: play(), pause(), resume(), seek(), stop(), _run(), _dispatch()
• tests/test_scheduler.py — 9 asyncio tests covering all scheduler behaviors

Decisions Made

• Absolute monotonic timestamps (D-07): fire_at = start_time + pause_offset + event.timestamp recalculated fresh each poll iteration — mathematical guarantee of <1ms drift per event over any duration
• pause_offset accumulation (D-09): resume() adds elapsed pause time so all future fire_at values stay correct
• seek() implemented as play() restart — simpler than maintaining an internal event index pointer, avoids state management complexity
• Scheduler sends {zone, animation, params} only — v:1 is transport's responsibility (confirmed by test asserting "v" not in cmd)

Deviations from Plan

None - plan executed exactly as written.

Issues Encountered

None — implementation matched plan specification precisely. All 9 tests pass on first run.

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• CHR-05 fulfilled: ChoreographyScheduler dispatches animation commands at absolute monotonic timestamps
• Ready for Phase 02-05 (beat detection) which will call scheduler.on_event via the callback hook
• Ready for Phase 03 TUI integration — scheduler is asyncio-native, Textual will wrap play()/pause()/resume()/seek() directly
• current_position property enables real-time timeline display in the TUI

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Phase: 02-app-core-audio Completed: 2026-04-03