# BRIEFING — 2026-10-09T08:10:00Z

## Mission
Implement Milestone M4 deliverables: Audio asset resolution, Mode A boundary smoothing concat with missing audio fallback, EBU R128 audio mastering with naming options, episode feature master assembly (Scenes 01-10 into ep01_full_feature_master_v1.mp4), assemble_ep01_feature.py upgrade, and comprehensive E2E verification test suite tests/test_production_pipeline_m4.py.

## 🔒 My Identity
- Archetype: worker
- Roles: implementer, qa
- Working directory: c:\Projects\KieuStory\.agents\teamwork\worker_m4_assembly_1
- Original parent: 97faf5e5-a830-491c-b78c-2af12175badf
- Milestone: M4 (Scene Concat, Audio Mastering & Final Assembly)

## 🔒 Key Constraints
- DO NOT CHEAT. All implementations must be genuine.
- Zero OpenCV Concat: Strict FFmpeg filter_complex concat ([v][a]) preserving 100% AAC 48kHz audio.
- Mode A (boundary_smoothing 30ms micro-fade with curve=qsin) default in concat_scene_shots to prevent timeline duration shrinkage.
- Two-Pass linear EBU R128 Loudness Normalization (-14.0 LUFS ± 0.5, TP <= -1.0 dBTP).
- Exclusive Write Ownership:
  * 05_Production_Pipeline/production_orchestrator.py
  * 05_Production_Pipeline/assemble_ep01_feature.py
  * 05_Production_Pipeline/audio_continuity_engine.py (if minor helper needed)
  * tests/test_production_pipeline_m4.py
- READ-ONLY: 04_Assets/characters/ (DO NOT MODIFY OR DELETE)
- PRESERVE: 04_Assets/archive/ep01_legacy_v1/ (DO NOT MODIFY OR DELETE)

## Current Parent
- Conversation ID: 97faf5e5-a830-491c-b78c-2af12175badf
- Updated: 2026-10-09T08:10:00Z

## Task Summary
- **What to build**:
  1. resolve_audio_asset() and resolve_scene_master() in production_orchestrator.py
  2. Upgrade concat_scene_shots() with mode="boundary_smoothing", CLI --mode, and silence fallback
  3. Upgrade master_scene_audio() with resolve_audio_asset and naming convention
  4. Implement assemble_episode_master() for Ep01 10 canonical scenes
  5. Upgrade assemble_ep01_feature.py for 10 scenes and _master_audio resolution
  6. Comprehensive E2E test suite tests/test_production_pipeline_m4.py
- **Success criteria**: 100% tests pass on test_production_pipeline_m4.py, test_production_pipeline_m3.py, test_adversarial_m3_audio_engine.py, test_critic_gate.py, test_tier5_pipeline_hardening.py with zero regressions.
- **Interface contracts**: PROJECT.md, blueprints from explorer_m4_1 and explorer_m4_2.
- **Code layout**: 05_Production_Pipeline/ and tests/

## Key Decisions Made
- Use Mode A (boundary_smoothing) default in concat_scene_shots to prevent timeline shrinkage across scenes with up to 27 shots.
- Support both _master_audio_v* and _cinematic_master_v* in candidate resolution.
- Both 10-scene campaign assembly and 15-scene feature assembly supported cleanly in assemble_ep01_feature.py.

## Change Tracker
- **Files modified**:
  * 05_Production_Pipeline/production_orchestrator.py: Added resolve_audio_asset, resolve_scene_master, EP01_CANONICAL_SCENES, assemble_episode_master; upgraded concat_scene_shots (Mode A default + silence fallback) and master_scene_audio; added CLI arguments.
  * 05_Production_Pipeline/assemble_ep01_feature.py: Upgraded resolve_scene_part for master_audio priority; added 10-scene campaign assembly support and EBU R128 mastering.
  * tests/test_production_pipeline_m4.py: Created comprehensive 15-test E2E verification test suite.
- **Build status**: PASS (All 15 M4 tests passed, 87 regression tests passed, 0 failures)
- **Pending issues**: none

## Quality Status
- **Build/test result**: 15 passed in test_production_pipeline_m4.py (9.50s), 16 passed in test_production_pipeline_m3.py (5.73s), 6 passed in test_adversarial_m3_audio_engine.py (28.69s), 30 passed in test_critic_gate.py (12.45s), 20 passed in test_tier5_pipeline_hardening.py.
- **Lint status**: clean
- **Tests added/modified**: tests/test_production_pipeline_m4.py (15 new test methods covering all 5 architectural groups)

## Artifact Index
- .agents/teamwork/worker_m4_assembly_1/DISPATCH.md — Task assignment
- .agents/teamwork/worker_m4_assembly_1/BRIEFING.md — Working memory
- .agents/teamwork/worker_m4_assembly_1/progress.md — Liveness tracker
- .agents/teamwork/worker_m4_assembly_1/handoff.md — Final handoff report
- tests/test_production_pipeline_m4.py — E2E test suite