# Task Assignment: Milestone M4 Iteration 2 Challenger 1 (Silent Clip Fallback & Audio Concat Probe)

## Timestamp
2026-10-09T08:54:00Z

## Assigned Subagent
- Role: Silent Clip Fallback & Audio Concat Challenger 1 (Iter 2)
- Type: teamwork_preview_challenger
- Working Directory: c:\Projects\KieuStory\.agents\teamwork\challenger_m4_iter2_1

## Context & Authoritative References
- Authoritative User Request: c:\Projects\KieuStory\.agents\teamwork\ORIGINAL_REQUEST.md
- Scope Document: c:\Projects\KieuStory\.agents\teamwork\orchestrator_1\PROJECT.md
- Worker Handoff: c:\Projects\KieuStory\.agents\teamwork\worker_m4_remediation_2\handoff.md
- Explorer Remediation Plan: c:\Projects\KieuStory\.agents\teamwork\explorer_m4_remediation_1\remediation_plan.md
- Previous Gate Status: c:\Projects\KieuStory\.agents\teamwork\orchestrator_1\GATE_STATUS.md

## Challenge Instructions
1. Empirically probe Fallback Concat with Silent Clips:
   - Run live Python test script concatenating video clips without audio tracks (`-an`) mixed with normal audio clips via `production_orchestrator.py:concat_scene_shots` fallback path.
   - Verify that `ffprobe` executable is correctly resolved without `FileNotFoundError`.
   - Verify that fallback concat generates silent audio track via `aevalsrc=0` without FFmpeg crash or stream specifier error.
   - Verify output file contains valid AAC 48kHz stereo stream.
2. Run test suites:
   - `python -m pytest tests/test_adversarial_m4_audio_concat_probe.py -v` (verify 5/5 PASS)
   - `python -m pytest tests/test_production_pipeline_m4.py -k "test_05_fallback" -v` (verify PASS)
3. Deliver your empirical challenge verdict (APPROVE or REQUEST_CHANGES) in:
   `c:\Projects\KieuStory\.agents\teamwork\challenger_m4_iter2_1\handoff.md`.
4. Send a completion message to parent orchestrator.