cinematic-ffmpeg

name	cinematic-ffmpeg
description	Cinematic ffmpeg delivery toolkit for Grok Imagine Studio. Concatenates trims and social-crops polished clips after Assembly Editor and AI Polish Director. Activate when building delivery files muxing reels or exporting 9x16 1x1 and 16x9 variants. Uses Grok 4.5 orchestration.

Cinematic FFmpeg v3.7.1 (Grok 4.5 · Delivery Toolkit)

Tool skill — post-polish technical assembly and platform export. Requires ffmpeg (and ideally ffprobe) on PATH. Orchestration is Grok 4.5; this skill does not spend Imagine API credits.

Model Layer (Grok 4.5 · studio v3.7.1)

Layer	Slug	When
Orchestration (default)	grok-4.5	Concat, social crops, delivery packages
Long-context (opt-in)	grok-4.3	Rare — huge multi-reel manifests only
Grok Build CLI	grok-4.5 · grok-build	Skills / coding (≥ 0.2.93)
Imagine Video	grok-imagine-video / 1.5	1.0 cost · 1.5 native audio
Imagine Image	grok-imagine-image / quality	Stills / hero plates

Prefer stable prompt_cache_key on multi-turn grok-4.5 loops. Reasoning medium for routine concat/crop; high if EDL timing, multi-format packages, or re-encode quality tradeoffs are non-trivial. Opt into grok-4.3 only for 1M. Imagine tools are not used here. Registry: tools/models.py · references/agents/MODEL_LAYER_v3.7.1.md · models verify.

When to Activate

• After Assembly Editor EDL is approved
• After AI Polish Director writes polished masters
• Building rough cuts, reels, or multi-aspect social packages
• Before platform upload / client delivery
• User says: ACTIVATE CINEMATIC_FFMPEG, BUILD DELIVERY, EXPORT SOCIAL CROPS, CONCAT POLISHED REEL

When NOT to Use

Situation	Instead
Unpolished / No-Go clips	QA + AI Polish first
Re-generate story content	Studio / Sequence Director
Upscale / face restore	ai-polish-director / ai-video-upscaler
Subtitle burn-in design	Localization Specialist (then mux here if needed)

Pipeline Position

QA Go → Color Grade → AI Polish → Assembly EDL
  → Cinematic FFmpeg (this skill)
  → Studio Director sign-off / client handoff

Prerequisites

command -v ffmpeg && ffmpeg -version | head -1
# optional: command -v ffprobe
chmod +x .grok/skills/cinematic-ffmpeg/scripts/*.sh

Install on Debian/Kali: sudo apt-get install -y ffmpeg

Scripts

All paths relative to repo root. Prefer stream-copy (-c copy) when possible to avoid quality loss.

1. Concatenate polished clips (rough cut / reel)

Sorts *.mp4 / *.mov in the input directory and concat-demuxes:

bash .grok/skills/cinematic-ffmpeg/scripts/concat_clips.sh \
  artifacts/polished/<slug>/ \
  artifacts/delivery/<slug>/rough_cut.mp4

2. Trim to EDL in/out

bash .grok/skills/cinematic-ffmpeg/scripts/trim_clip.sh \
  artifacts/polished/<slug>/clip_002_polished.mp4 \
  artifacts/delivery/<slug>/clip_002_trim.mp4 \
  0.5 8.0
# args: start_sec duration_sec

Tries stream-copy first; falls back to re-encode if needed.

3. Social crops

Aspect tokens use colons in script args (not skill frontmatter): 9:16 · 1:1 · 16:9

bash .grok/skills/cinematic-ffmpeg/scripts/social_crop.sh \
  artifacts/delivery/<slug>/rough_cut.mp4 \
  artifacts/delivery/<slug>/vertical_9x16.mp4 \
  9:16

bash .grok/skills/cinematic-ffmpeg/scripts/social_crop.sh \
  artifacts/delivery/<slug>/rough_cut.mp4 \
  artifacts/delivery/<slug>/square_1x1.mp4 \
  1:1

bash .grok/skills/cinematic-ffmpeg/scripts/social_crop.sh \
  artifacts/delivery/<slug>/rough_cut.mp4 \
  artifacts/delivery/<slug>/landscape_16x9.mp4 \
  16:9

Pipeline readiness

Prefer sequence polish before sequence deliver. Automation: sequence deliver --strict-delivery exits 1 when no polished mp4s exist for the sequence slug. Soft default only warns.

Studio CLI (preferred for sequences)

# After polish — multi-format package
python tools/cinematic_studio_cli.py sequence deliver "Act 1" --formats 16:9,9:16,1:1
python tools/cinematic_studio_cli.py sequence deliver "Act 1" --dry-run

Uses polished clips under the sequence slug and the same ffmpeg scripts when available (tools/sequence_delivery.py).

Delivery Presets (quick)

Package	Steps
Web reel 16×9	concat polished → optional pad via 16:9 crop script
Stories / Reels 9×16	concat or hero select → social_crop.sh … 9:16
Feed square 1×1	concat or hero → social_crop.sh … 1:1
Festival master	polish at festival preset first → concat with -c copy only if same codec/res

Delivery Checklist

1. Assembly Editor EDL applied (trim before concat if cut points required)
2. All segments QA Go + polished (artifacts/polished/…)
3. Concat → verify duration vs EDL target (ffprobe)
4. Optional social crops per platform brief
5. Audio present and in sync on masters
6. Log Project Bible:

   [DELIVERY_MANIFEST: slug=…, rough_cut=…, formats=16x9+9x16+1x1, ffmpeg=stream_copy|reencode]
   

7. Hand off to Studio Director / Localization if burn-in needed

Output Report

CINEMATIC FFMPEG DELIVERY · v3.7.1
Inputs: <n clips / path>
Ops: <concat|trim|crop|sequence deliver>
Outputs:
  - artifacts/delivery/…
Duration check: <ok|mismatch …>
Codec: <copy|reencode>
Next: Studio Director sign-off | Localization | upload

Integration

Partner	Role
Assembly Editor	EDL / cut order
AI Polish Director	Polished sources only
Localization Specialist	Subs / SDH before or after mux
Studio Director	Final package approval
GitHub Repo Manager	Do not commit large masters unless intentional

Never concat unpolished or No-Go clips into delivery masters.

Quality Bar

• Prefer stream copy for concat when all sources share codec/resolution/framerate
• Re-encode only when trim/crop filters require it
• Spot-check first/last frames and audio after every mux
• Save under artifacts/delivery/ — not inside skill directories

Reasoning (Grok 4.5)

Task	Reasoning
Routine concat/crop	medium
Multi-format package / re-encode risk	high

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Cinematic FFmpeg v3.7.1 — Grok 4.5 delivery toolkit · post-polish concat trim crop · sequence deliver