Video Use

# Video Use

## Principle

1. **LLM reasons from raw transcript + on-demand visuals.** The only derived artifact that earns its keep is a packed phrase-level transcript (`takes_packed.md`). Everything else — filler tagging, retake detection, shot classification, emphasis scoring — you derive at decision time.
2. **Audio is primary, visuals follow.** Cut candidates come from speech boundaries and silence gaps. Drill into visuals only at decision points.
3. **Ask → confirm → execute → iterate → persist.** Never touch the cut until the user has confirmed the strategy in plain English.
4. **Generalize.** Do not assume what kind of video this is. Look at the material, ask the user, then edit.
5. **Artistic freedom is the default.** Every specific value, preset, font, color, duration, pitch structure, and technique in this document is a *worked example* from one proven video — not a mandate. Read them to understand what's possible and why each worked. Then make your own taste calls based on what the material actually is and what the user actually wants. **The only things you MUST do are in the Hard Rules section below.** Everything else is yours.
6. **Invent freely.** If the material calls for a technique not described here — split-screen, picture-in-picture, lower-third identity cards, reaction cuts, speed ramps, freeze frames, crossfades, match cuts, L-cuts, J-cuts, speed ramps over breath, whatever — build it. The helpers are ffmpeg and PIL. They can do anything the format supports. Do not wait for permission.
7. **Verify your own output before showing it to the user.** If you wouldn't ship it, don't present it.

## Hard Rules (production correctness — non-negotiable)

These are the things where deviation produces silent failures or broken output. They are not taste, they are correctness. Memorize them.

1. **Subtitles are applied LAST in the filter chain**, after every overlay. Otherwise overlays hide captions. Silent failure.
2. **Per-segment extract → lossless `-c copy` concat**, not single-pass filtergraph. Otherwise you double-encode every segment when overlays are added.
3. **30ms audio fades at every segment boundary** (`afade=t=in:st=0:d=0.03,afade=t=out:st={dur-0.03}:d=0.03`). Otherwise audible pops at every cut.
4. **Overlays use `setpts=PTS-STARTPTS+T/TB`** to shift the overlay's frame 0 to its window start. Otherwise you see the middle of the animation during the overlay window.
5. **Master SRT uses output-timeline offsets**: `output_time = word.start - segment_start + segment_offset`. Otherwise captions misalign after segment concat.
6. **Never cut inside a word.** Snap every cut edge to a word boundary from the Scribe transcript.
7. **Pad every cut edge.** Working window: 30–200ms. Scribe timestamps drift 50–100ms — padding absorbs the drift. Tighter for fast-paced, looser for cinematic.
8. **Word-level verbatim ASR only.** Never SRT/phrase mode (loses sub-second gap data). Never normalized fillers (loses editorial signal).
9. **Cache transcripts per source.** Never re-transcribe unless the source file itself changed.
10. **Parallel sub-agents for multiple animations.** Never sequential. Spawn N at once via the `Agent` tool; total wall time ≈ slowest one.
11. **Strategy confirmation before execution.** Never touch the cut until the user has approved the plain-English plan.
12. **All session outputs in `<videos_dir>/edit/`.** Never write inside the `video-use/` project directory.

Everything else in this document is a worked example. Deviate whenever the material calls for it.

## Directory layout

The skill lives in `video-use/`. User footage lives wherever t