Motion video - render the story, prove it once
A demo-video films the real product to prove it. A motion video renders the story to sell or explain it. The mix is the opposite: a marketing film is mostly rendered scenes with one real capture stitched in as proof. Get that inversion wrong and you have either a screen-recording that bores or a cartoon that convinces no one.
The contract
Four rules. They are the ones an agent under time pressure abandons first, which is why they are not optional. Repeat the bolded phrase in your reasoning as you work; it is the behaviour.
- Wrapper, not proof. Rendered and mocked scenes are the WRAPPER; the real capture is the
PROOF. Never pass a rendered UI off as a live screen recording. When a figure is illustrative, say so on screen. This is demo-video's "annotate never substitute" ethic moved up one level: mocks are legitimate in the wrapper, banned inside the proof beat.
A screenshot with a camera move is NOT the proof beat. This is the failure this rule exists to catch, and it is seductive because PageCam over a still looks expensive. It is still a photograph. A film built entirely of glides over stills feels dead on the first watch and the client says so: nothing is ever being USED. The proof beat must contain MOTION THE PRODUCT MADE - a cursor travelling, characters landing one at a time, a list re-filtering as the query lands, a page actually loading. If no scene in the storyboard has that, the film has no proof layer, whatever the screenshots look like. Verify it by asking of each beat: could this frame have come from a PNG? If yes for every beat, go back to step 4.
- Frame-clock, not wall-clock. Every animation is driven by Remotion's
useCurrentFrame().
framer-motion, CSS transitions, requestAnimationFrame, setTimeout, Date.now() all render FROZEN, because Remotion seeks a synthetic clock frame by frame. This is the single biggest surprise; internalise it before you write a scene. (references/remotion.md.)
- Brand-match verbatim. Pull the real font, logo mark, wordmark, and palette from the
product's OWN repo and use them exactly. An approximated brand reads as fake and undoes the film. (references/brand-match.md.)
- Figures reconcile. A mocked ledger still balances; a mocked chart's bars still sum to its
headline. No fabricated numbers, no prices the brand keeps private, no success rates or compliance claims, and nothing that reveals HOW a sensitive capability works if the brand does not want it shown. Marketing gets a warmer voice, never a pass on truth.
Steps
0. Preflight
Node + ffmpeg present. Locate the product's repo (you need its real brand assets) and confirm it runs with demo data (you need one real beat). Remotion is free for teams of 3 or fewer; 4+ needs a paid licence - flag it before promising a Remotion build.
1. Storyboard - GATE, same as demo-video
One row per scene: scene | shows | real or rendered | motion | narration | dur. Mark every scene real or rendered, and name the ONE real proof beat. Show it and stop until the user approves. This is the cheapest point to change the film; after scenes are rendered every edit re-renders and re-times. (Storyboard format: demo-video/references/storyboard.md, adapted - the "proof" column becomes "real or rendered".)
1.5 Target formats - GATE with the storyboard
A film rarely ships as one file: the same story goes to 16:9 YouTube, 9:16 TikTok/Reels/Shorts, and 4:5 feed. Ask which platforms and placements it ships to (a multi-select), collapse them to the minimal master-ratio set - almost always a subset of {9:16, 16:9, 4:5, 1:1} - and note each one's UI safe zone. Two rules the agent under pressure breaks: reframe, never crop the extremes (16:9 to 9:16 discards ~56% of the frame and must be re-authored, not cropped), and compose inside the safe box (keep every title and logo clear of the caption bar, action rail, and CTA button the platform paints over the video). Decide this BEFORE building scenes - it sets how each scene lays out in vertical vs landscape. Remotion makes the cut cheap: one component set renders at any width/height via useVideoConfig(). (references/platform-formats.md.)
2. Brand-match
Find the real font (next/font or tailwind config), logo (SVG/component), wordmark, and palette in the product repo. Wire them into the Remotion project. Do this FIRST - it changes every scene. (references/brand-match.md.)
3. Build the rendered scenes
An isolated Remotion project, one component per scene, everything on useCurrentFrame(). If the film targets more than one aspect ratio, branch each scene's layout on orientation (useVideoConfig()) and keep content inside the safe box - do not author for 16:9 and crop to 9:16 later. Setup, the frame-clock discipline, fonts, and rendering are in references/remotion.md; the format matrix and safe zones are in references/platform-formats.md.
Start from the carried motion kit, not from scratch. assets/motion/ holds the shotcraft pieces every film reuses, already brand-parameterised and format-aware: PageCam (2.5D camera over a real screenshot), DigitRoll (a number landing), FlashCut (a hard tonal break), Caption, VerticalTicker (volume), and deterministic helpers/. Copy what the storyboard needs into the project's src/motion/ and pass the brand tokens in. Read assets/motion/README.md first - it says when each one earns its place, and which two upstream defaults (hardcoded 1920x1080 framing, and the Ink Press amber) are deliberately parameterised because a naive re-copy breaks rules 1.5 and 3.
Reach past the kit for anything it does not cover: the remaining ~100 shot cards, the preview gallery, and the SFX/BGM set stay REFERRED, shopped per beat from the installed video-shotcraft skill per references/shotcraft-bridge.md. Our guardrails and three ratios wrap all of it. Rendered scenes only - the real-proof beat stays demo-video, which shotcraft cannot record.
A beat that shows a figure should usually ROLL it (DigitRoll), not fade it in: a rolling number reads as the system computing, a fading number reads as a caption. This is the most common miss.
4. Capture the real beats
The proof: the real product doing the real thing, captured crisply with the demo-video skill's harness. Do not rebuild the product's own screen in Remotion when the real one can be filmed - that is the wrapper-not-proof line.
"ONE beat" is the floor, not the target. A marketing film carries as many real beats as it has claims; a 60s hero comfortably holds three or four, and they are what make it feel alive. Budget them at the storyboard gate, not after the rendered scenes are built.
What to capture, in order of how alive it reads: typing (characters landing one at a time in a real input), filtering (a list collapsing as the query lands - it proves the data is real and the app is responding), navigating (pages actually loading, nav highlighting), then plain scrolling. Record the cursor: a visible pointer that TRAVELS to its target sells the interaction, and a cursor that teleports is the giveaway that a "recording" was faked. Move the mouse in steps.
Keep every take READ-ONLY on a real tenant - type but do not send, filter but do not save, navigate but do not submit. A take that would mutate needs the owner's explicit go-ahead, and on a production tenant the answer is usually a staging one instead.
Two things that ruin otherwise good footage, both cheap to prevent:
- Browser chrome in frame.
--kiosk is unreliable under automation; crop the top band in
ffmpeg instead. Crop the TOP only, then PAD back to the target ratio - cropping the sides to "fix" the aspect slices the app's own nav rail and reads as a broken capture.
- Trimming by guess. Navigation is slower than it feels; the action often starts 5-8s in.
Extract frames from the raw take, find where the action actually begins, then trim.
5. Stitch
Rendered scenes + the real beat, crossfaded with ffmpeg. scripts/stitch.mjs is the reusable xfade chain; edit its clip list. Derive final timestamps from the DELIVERED mp4, never from planned scene lengths (same Gate-3 rule as demo-video). Assembly variants and the ffmpeg recipe: pitch-package/references/stitching.md.
6. Narrate - optional
A marketing film often ships silent (motion + on-screen text, autoplay-muted). If it needs a voiceover, write it in the pitch-craft marketing register, timed to the encoded mp4.
7. Verify
Watch every scene as an image. Figures reconcile. Brand matches the real app. No scene overclaims or leaks. The real beat is unmistakably the real product. Render each selected format (scripts/render-formats.mjs) and watch it at its TRUE ratio - a layout that reads in 16:9 can collapse in 9:16, and nothing critical may sit inside a platform safe zone.
References
references/remotion.md - the Remotion setup that works: isolated project, the frame-clock
discipline, brand fonts, rendering. Read before writing a scene.
references/brand-match.md - how to find and wire the product's real font, logo, and palette.scripts/stitch.mjs - the ffmpeg xfade stitcher for rendered scenes + the real beat.references/platform-formats.md - target-platform picker, the minimal master-ratio set, per-placement
UI safe zones, the export/codec rule, and the Remotion multi-format recipe. Read when the film ships to more than one placement (any ad or multi-channel post).
assets/motion/ - the CARRIED motion kit: PageCam, DigitRoll, FlashCut, Caption, VerticalTicker,
and deterministic helpers, brand-parameterised and format-aware, with LICENSE.upstream. Copy into the film's project. Read its README before building a scene.
references/shotcraft-bridge.md - how to leverage the rest of the external video-shotcraft
motion/sound library (what is carried vs referred, the RENDERED-vs-RECORDED boundary, the card-to-beat map, and the guardrail overlay). Read when a scene needs motion the kit does not carry.
scripts/render-formats.mjs - render every chosen ratio from one Remotion project (Film-<id> compositions).- Shared engines this skill leans on, never duplicates: demo-video (the real proof beat),
pitch-craft (narration), pitch-package/references/stitching.md (assembly).
