# DISPATCH — Explorer 1 (Milestone M4: Concat, Audio Mastering & EBU R128 Architecture)

## Mission
Investigate and design the technical blueprint for Milestone M4:
1. **Audio-Preserving FFmpeg Concat (`AGENTS.md §4`)**:
   - Inspect `concat_scene_shots` in `05_Production_Pipeline/production_orchestrator.py`.
   - Verify FFmpeg filter_complex concat syntax: `[0:v:0][0:a:0]...concat=n=N:v=1:a=1[v][a]`.
   - Verify that 100% of audio streams (AAC 48kHz) are retained with zero OpenCV video-only concat.
2. **EBU R128 Cinematic Audio Mastering (`AGENTS.md §5`, `CINEMATIC_AUDIO_PIPELINE.md`)**:
   - Inspect `05_Production_Pipeline/audio_continuity_engine.py` and `master_scene_audio` in `production_orchestrator.py`.
   - Verify 2-pass `loudnorm` filter configuration: Integrated Loudness `-14 LUFS` (±0.5), True Peak `-1.0 dBTP`, LRA `9-11 LU`.
   - Verify 4-stem mixing and dynamic ducking support (BGM, Ambience, Foley, Dialogue).
   - Check available audio assets in `04_Assets/audio_sfx/` (e.g. `scene01_bgm.m4a`).
3. **Multi-Scene Concatenation for Ep01 Master**:
   - Design the multi-scene master concat function `assemble_episode_master("ep01", scene_ids)` stitching all 10 scene masters into the final Ep01 Feature Cut (`06_Exports/ep01_master_feature.mp4`).

## Mandatory Reading
- `c:\Projects\KieuStory\.agents\teamwork\ORIGINAL_REQUEST.md` (read completely first)
- `c:\Projects\KieuStory\.agents\teamwork\orchestrator_1\PROJECT.md`
- `c:\Projects\KieuStory\AGENTS.md` (Sections 4, 5, and 6)
- `c:\Projects\KieuStory\00_Project_Bible\CINEMATIC_AUDIO_PIPELINE.md`

## Output
Write your findings and implementation blueprint to:
`c:\Projects\KieuStory\.agents\teamwork\explorer_m4_1\m4_concat_audio_blueprint.md`
and write your handoff report to:
`c:\Projects\KieuStory\.agents\teamwork\explorer_m4_1\handoff.md`.
Notify parent orchestrator when complete.

## 2026-10-09T07:45:04Z
You are Explorer 1 for Milestone M4 (Scene Concat, Audio Mastering & EBU R128 Architecture).

Your working directory is: c:\Projects\KieuStory\.agents\teamwork\explorer_m4_1

MANDATORY FIRST STEP:
Read c:\Projects\KieuStory\.agents\teamwork\ORIGINAL_REQUEST.md completely. Do not skip this.
Read c:\Projects\KieuStory\.agents\teamwork\orchestrator_1\PROJECT.md.
Read c:\Projects\KieuStory\.agents\teamwork\explorer_m4_1\DISPATCH.md.
Read AGENTS.md (Sections 4, 5, and 6) and 00_Project_Bible/CINEMATIC_AUDIO_PIPELINE.md.

INVESTIGATION OBJECTIVES:
1. FFmpeg Filter Complex Concat Architecture:
   - Inspect concat_scene_shots in 05_Production_Pipeline/production_orchestrator.py.
   - Verify filter_complex concat syntax: [0:v:0][0:a:0]...concat=n=N:v=1:a=1[v][a] preserving 100% AAC 48kHz audio.
2. EBU R128 Audio Mastering & Normalization:
   - Inspect 05_Production_Pipeline/audio_continuity_engine.py and master_scene_audio in production_orchestrator.py.
   - Verify 2-pass loudnorm configuration: I=-14 LUFS, TP=-1.0 dBTP, LRA=9-11 LU, 48kHz stereo AAC.
   - Check BGM assets in 04_Assets/audio_sfx/ and dynamic ducking implementation.
3. Multi-Scene Master Assembly:
   - Design assemble_episode_master("ep01") to stitch all 10 scene masters into 06_Exports/ep01_full_feature_master_v1.mp4.
4. Deliver detailed blueprint in c:\Projects\KieuStory\.agents\teamwork\explorer_m4_1\m4_concat_audio_blueprint.md and handoff report in c:\Projects\KieuStory\.agents\teamwork\explorer_m4_1\handoff.md.
5. Send message to parent orchestrator when complete.