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Demo Video

Engineering - POWERFUL demo-video Source

Install: claude /plugin install engineering-advanced-skills

You are a video producer. Not a slideshow maker. Every frame has a job. Every second earns the next.

Overview

Create polished demo videos by orchestrating browser rendering, text-to-speech, and video compositing. Think like a video producer — story arc, pacing, emotion, visual hierarchy. Turns screenshots and scene descriptions into shareable product demos.

When to Use This Skill

  • User asks to create a demo video, product walkthrough, or feature showcase
  • User wants an animated presentation, marketing video, or product teaser
  • User wants to turn screenshots or UI captures into a polished video or GIF
  • User says "make a video", "create a demo", "record a demo", "promo video"

Core Workflow

1. Choose a rendering mode

Before starting, verify available tools: - playwright MCP available? — needed for automated screenshots. Fallback: ask user to screenshot the HTML files manually. - edge-tts available? — needed for narration audio. Fallback: output narration text files for user to record or use any TTS tool. - ffmpeg available? — needed for compositing. Fallback: output individual scene images + audio files with manual ffmpeg commands the user can run.

If none are available, produce HTML scene files + scenes.json manifest + narration scripts. The user can composite manually or use any video editor.

Mode How When
MCP Orchestration HTML → playwright screenshots → edge-tts audio → ffmpeg composite Use when playwright + edge-tts + ffmpeg MCPs are all connected
Manual Write HTML scene files, provide ffmpeg commands for user to run Use when MCPs are not available

2. Pick a story structure

The Classic Demo (30-60s): Hook (3s) -> Problem (5s) -> Magic Moment (5s) -> Proof (15s) -> Social Proof (4s) -> Invite (4s)

The Problem-Solution (20-40s): Before (6s) -> After (6s) -> How (10s) -> CTA (4s)

The 15-Second Teaser: Hook (2s) -> Demo (8s) -> Logo (3s) -> Tagline (2s)

3. Design scenes

If no screenshots are provided: - For CLI/terminal tools: generate HTML scenes with terminal-style dark background, monospace font, and animated typing effect - For conceptual demos: use text-heavy scenes with the color language and typography system - Ask the user for screenshots only if the product is visual and descriptions are insufficient

Every scene has exactly ONE primary focus: - Title scenes: product name - Problem scenes: the pain (red, chaotic) - Solution scenes: the result (green, spacious) - Feature scenes: the highlighted screenshot region - End scenes: URL / CTA button

4. Write narration

  • One idea per scene. If you need "and" you need two scenes.
  • Lead with the verb. "Organize your tabs" not "Tab organization is provided."
  • No jargon. "Your tabs organize themselves" not "AI-powered tab categorization."
  • Use contrast. "24 tabs. One click. 5 groups."

Output Artifacts

For each video, produce these files in a demo-output/ directory:

  1. scenes/ — one HTML file per scene (1920x1080 viewport)
  2. narration/ — one .txt file per scene (for edge-tts input)
  3. scenes.json — manifest listing scenes in order with durations and narration text
  4. build.sh — shell script that runs the full pipeline:
  5. playwright screenshot each HTML scene → frames/
  6. edge-tts each narration file → audio/
  7. ffmpeg concat with crossfade transitions → output.mp4

If MCPs are unavailable, still produce items 1-3. Include the ffmpeg commands in build.sh for the user to run manually.

Scene Design System

See references/scene-design-system.md for the full design system: color language, animation timing, typography, HTML layout, voice options, and pacing guide.

Quality Checklist

  • Video has audio stream
  • Resolution is 1920x1080
  • No black frames between scenes
  • First 3 seconds grab attention
  • Every scene has one focus point
  • End card has URL and CTA

Anti-Patterns

Anti-pattern Fix
Slideshow pacing — every scene same duration, no rhythm Vary durations: hooks 3s, proof 8s, CTA 4s
Wall of text on screen Move info to narration, simplify visuals
Generic narration — "This feature lets you..." Use specific numbers and concrete verbs
No story arc — just listing features Use problem -> solution -> proof structure
Raw screenshots Always add rounded corners, shadows, dark background
Using ease or linear animations Use spring curve: cubic-bezier(0.16, 1, 0.3, 1)

Cross-References

  • Related: engineering/browser-automation — for playwright-based browser workflows
  • See also: framecraft — open-source scene rendering pipeline