🎬 The Video Studio β€” how /demo-video works

one command, five robots, zero hand-editing Β· Synexar Β· July 6, 2026

THE BIG IDEA: the transcript is the edit timeline.

Every video is text + code. The narration file defines the scenes; the footage is cut to fit the words. Change a sentence β†’ the whole film re-edits itself. Nothing is ever dragged around in a video editor.

Why it doesn't look like a screen recording 🧐

  • No stutter, ever: title cards are tiny web pages rendered one frame at a time (30 perfect screenshots per second) β€” like a Pixar render, not a screen grab.
  • The cursor is an actor: a synthetic cursor glides on eased curves, like a calm human hand.
  • The "keynote look": every product shot is re-framed in a floating browser device, brightened, on a navy stage.
  • Real product, real staging: nothing is mocked β€” the robot clicks the actual app.

The assembly line β€” what happens when the skill runs

β‘ 
Prep the set

Seed clean synthetic patients on staging β€” unique names, tidy schedule, zero real data.

PHI check: zero foreign rows

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β‘‘
Film

A Playwright robot drives the real app in a headless browser, recording 1080p while it clicks, types and scrolls.

Every action drops a timestamp mark β†’ the cut map.

footage = reusable asset library

➜
β‘’
Voice & music

The script file β†’ ElevenLabs narrators (Brian / Jessica). Each line's length becomes its scene's length.

Music beds generated once, reused & extended.

swap voice = 1 env variable

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β‘£
Cards & cinema

Brand cards = HTML animations rendered frame-by-frame (deterministic, buttery).

Veo 3.1 makes the cinematic shots β€” corridors, sunrises, porch swings (~$3 per 8s).

light brand, refined lockup

➜
β‘€
Assemble Β· QA Β· ship

FFmpeg glues it: crossfades, music ducks under the voice, broadcast loudness.

QA = look at pixels (frame grids) + listen at head/mid/tail.

deliver: chat + Azure links

Two grammars β€” demos vs commercials

πŸ“˜ Demo β€” audio-led

The narration drives. A scene lasts exactly as long as its sentence (footage freezes politely if the voice runs long).

  • Your review note = a text edit, and the film rebuilds
  • Used for: 4 workflow demos + the 6:30 unified tour

🎞️ Commercial β€” picture-led

Fixed visual beats drive: 8s cinema shots, 5s product money-shots, kinetic statement cards. The voice is placed into the beats (long lines politely push the next one β€” never collide).

  • Money-shots are re-sliced from demo footage β€” never re-filmed
  • Used for: the final pair β€” 60s Brian & 60s Jessica

The iterate loop β€” your words in, new cut out

πŸŽ™οΈ your voice note ➜ edit the script / swap a shot ➜ rebuild (minutes) ➜ QA grids + loudness ➜ πŸ“¦ new cut + link

this exact loop ran ~10 times over two days: demo β†’ 4 demos β†’ unified tour β†’ brand v2.5 β†’ commercials β†’ 90s β†’ 60s final pair

The gotcha wall β€” scars that became rules

πŸ‘€ Verify pixels, not marks. The robot once "passed" while the screen showed a sign-in page. Now every cut is frame-grid inspected.
πŸ”Š Listen at head/mid/tail. A silent first 8 seconds shipped once. Never again β€” loudness is measured at three points on the final file.
🎡 AI music fades early. ElevenLabs quietly fades ~10s before the length you asked for. Ask longer, check the tail, or self-extend the track.
πŸŽ₯ Veo won't film procedure rooms. The safety filter returns nothing β€” reword to corridors, lobbies, porches. (And it may sneak a side profile past "face not visible" β€” always judge the frames.)
πŸ” Patient links carry their key. Patient Connect keeps tokens in memory only (by PHI design) β€” every filmed URL needs its magic-link token.
πŸ“ Save every generation script. One narration set was made ad-hoc and its text was lost β€” recovered by transcribing our own mp3s. Now everything lands in the kit immediately.

The economics

πŸ’΅ Whole program

~$31 of Veo shots + pennies of narration.
4 demos, a 6:30 tour (two voices), 6 commercials β†’ 2 finals.

⏱️ Locked format speed

The Jessica 60 was pure configuration: same script, 3 new shots, one config entry β€” first-try assembly.

♻️ Nothing is precious

Every cut rebuilds from the committed kit + staging. The skill file carries every rule & scar β€” the next session starts where this one ended.

β€” drawn by Samantha Β· tap any box to flag it, notes go in the tray β†˜ β€”