Agent VFX

agentvfx

You direct; the engine renders. You never write shader code for a clip. You pick a template, a preset and a few typed parameters, write them into an FX score (JSON), and the engine renders it in headless Chrome (WebGL2), encodes H.264 with ffmpeg, and audits it for flashes.

Run every command from this folder (the skill root). Paths inside a score resolve against the current directory.

1. Check the machine

node scripts/vfx.mjs doctor

ok: true means Chrome with GPU WebGL2 and ffmpeg were found. Otherwise read blockers and tell the user what to install (CHROME_PATH, FFMPEG_PATH). Blender 5.x is needed only for plates (BLENDER_PATH).

2. Pick a look

node scripts/vfx.mjs list            # family, template id, input kind, presets
node scripts/vfx.mjs list --json     # with descriptions

input says what a template needs: generative (nothing), footage (input.video), or either. Start from a preset; change two or three parameters at most per round. Show the user the result before inventing more.

3. Write the score

Schema: schemas/fx-score.schema.json. Minimal:

{ "version": 1, "template": "lattice", "preset": "vermilion-fine",
  "input": { "video": "test-media/clip-01.mp4", "audio": "test-media/beat-132.mp3" },
  "durationSec": 4, "seed": 47, "out": "my-lattice" }

• durationSec is 3–5. seed makes the render repeatable.
• params override the preset (names and ranges come from the template's fx.json).
• bindings tie a parameter to an audio feature (bass, onset, beat, bands.N, …) with gain, offset, attackMs, releaseMs. Keep attack on the onset frame and release short (about 60 ms): snappy reads as professional, heavy smoothing reads as a demo.
• hits fire an extra template on an onset or beat; cuts hard-cut the stack on a beat; stack layers up to two templates over the base.
• labels and textStyle set the engine's text layer (installed fonts by name; generic fallback when missing).

Check it without rendering:

node scripts/vfx.mjs validate my-score.json

4. Render and look

node scripts/vfx.mjs render my-score.json --out out/my-lattice --width 640 --height 360

Preview small first (640x360), then raise the size for the final. The command prints JSON with the film path, the flash result and the stills. Open stills/sheet.png and every strip before you describe the clip to anyone. A render you have not looked at is not done.

5. Flash safety

Every render carries a flash audit (general and red flashes per second, WCAG 2.3.1 style). Default mode stage keeps full intensity and writes SAFETY.txt when limits are exceeded. "safety": { "mode": "broadcast-safe" } enforces the limits; "safeVariant": true adds film.safe.mp4 beside the full version. Tell the user plainly when a clip exceeds the limits.

6. Background plates (optional, Blender)

node scripts/plate.mjs --scene terminalcore --shot gallery --out out/plate --width 640 --height 360 --seconds 4

Procedural scenes, no downloaded assets. Use the plate's film.mp4 as input.video. --quality final is slow (about 2 minutes per 1080p frame); ask before starting one. See references/plates.md.

7. Silent loops

node scripts/loop.mjs out/my-lattice/film.mp4 reels/my-lattice.mp4 --preview reels/preview/my-lattice.webp --audit out/my-lattice/loop-flash.json

Plays the clip forward then backward (no seam, no audio track) and flash-audits the loop played twice. Exit code 3 means the loop exceeds the flash limits. Reversing can double the flashes around a turn; --hold 6 pauses six frames at each turn, which often brings such a loop back inside the limit. A red change that becomes a red flash when reversed cannot be fixed this way — say so and let the user decide.

8. Live on a web page

node scripts/export-web.mjs lattice collage --out out/web

Writes a self-contained runtime, the chosen templates and a demo page. Respects prefers-reduced-motion. See references/web.md.

Rules

• Never ship or commit music you do not have the rights to redistribute. A render's motion may come from a track while the published loop stays silent.
• References inspire; they are not copied. Do not reproduce a frame, logo, mark or font file from someone else's work.
• Do not bundle font files. Name installed fonts; they fall back when absent.

More

• references/template-format.md — how a template is built (fx.json, passes, presets, text layer).
• references/plates.md — Blender plates.
• references/web.md — web runtime API.