1nfsh-s3/explainer-video-guide

Install the belt CLI skill: npx skills add belt-sh/cli

Explainer Video Guide

Create explainer videos from script to final cut via inference.sh CLI.

Quick Start

Requires inference.sh CLI (belt). Install instructions

belt login

# Generate a scene for an explainer
belt app run google/veo-3-1-fast --input '{
  "prompt": "Clean motion graphics style animation, abstract data flowing between connected nodes, blue and white color scheme, professional corporate aesthetic, smooth transitions"
}'

Script Formulas

Problem-Agitate-Solve (PAS) — 60 seconds

| Section | Duration | Content | Word Count | |---------|----------|---------|------------| | Problem | 10s | State the pain point the viewer has | ~25 words | | Agitate | 10s | Show why it's worse than they think | ~25 words | | Solution | 15s | Introduce your product/idea | ~35 words | | How It Works | 20s | Show 3 key steps or features | ~50 words | | CTA | 5s | One clear next action | ~12 words |

Before-After-Bridge (BAB) — 90 seconds

| Section | Duration | Content | |---------|----------|---------| | Before | 15s | Show the current frustrating state | | After | 15s | Show the ideal outcome | | Bridge | 40s | Explain how your product gets them there | | Social Proof | 10s | Quick stat or testimonial | | CTA | 10s | Clear next step |

Feature Spotlight — 30 seconds (social)

| Section | Duration | Content | |---------|----------|---------| | Hook | 3s | Surprising fact or question | | Feature | 15s | Show one feature solving one problem | | Result | 7s | The outcome/benefit | | CTA | 5s | Try it / Learn more |

Pacing Rules

| Content Type | Words Per Minute | Notes | |-------------|-----------------|-------| | Standard narration | 150 wpm | Conversational pace | | Complex/technical | 120 wpm | Allow processing time | | Energetic/social | 170 wpm | Faster for short-form | | Children's content | 100 wpm | Clear and slow |

Key rule: 1 scene per key message. Don't pack multiple ideas into one visual.

Scene Duration Guidelines

• Establishing shot: 3-5 seconds
• Feature demonstration: 5-8 seconds
• Text/stat on screen: 3-4 seconds (must be readable)
• Transition: 0.5-1 second
• CTA screen: 3-5 seconds

Visual Production

Scene Types

# Product in context
belt app run google/veo-3-1-fast --input '{
  "prompt": "Clean product demonstration video, hands typing on a laptop showing a dashboard interface, bright modern office, soft natural lighting, professional"
}'

# Abstract concept visualization
belt app run bytedance/seedance-2-0 --input '{
  "prompt": "Abstract motion graphics, colorful data streams connecting floating geometric shapes, smooth fluid animation, dark background with glowing elements, tech aesthetic",
  "generate_audio": true
}'

# Lifestyle/outcome shot
belt app run google/veo-3-1-fast --input '{
  "prompt": "Happy person relaxing on couch with laptop, smiling at screen, bright airy living room, warm afternoon light, satisfied customer feeling, lifestyle commercial style"
}'

# Before/after comparison
belt app run falai/flux-dev-lora --input '{
  "prompt": "Split screen comparison, left side cluttered messy desk with papers and stress, right side clean organized minimalist workspace, dramatic difference, clean design"
}'

Image-to-Video for Scenes

# Generate a still frame first
belt app run falai/flux-dev-lora --input '{
  "prompt": "Professional workspace with glowing holographic interface, futuristic but clean, blue accent lighting"
}'

# Animate it
belt app run falai/wan-2-5-i2v --input '{
  "prompt": "Gentle camera push in, holographic elements subtly floating and rotating, soft ambient light shifts",
  "image": "path/to/workspace-still.png"
}'

Voiceover Production

Script Writing Tips

• Short sentences. Max 15 words per sentence.
• Active voice. "You can track your data" not "Your data can be tracked."
• Conversational tone. Read it aloud — if it sounds stiff, rewrite.
• One idea per sentence. One sentence per visual beat.

Generating Voiceover

# Professional narration with Dia TTS
belt app run falai/dia-tts --input '{
  "prompt": "[S1] Tired of spending hours on reports that nobody reads? There is a better way. Meet DataFlow. It turns your raw data into visual stories... in seconds. Just connect your source, pick a template, and share. Try DataFlow free today."
}'

Pacing Control in TTS

| Technique | Effect | Example | |-----------|--------|---------| | Period . | Medium pause | "This changes everything. Here's how." | | Ellipsis ... | Long pause (dramatic) | "And the result... was incredible." | | Comma , | Short pause | "Fast, simple, powerful." | | Exclamation ! | Emphasis/energy | "Start building today!" | | Question ? | Rising intonation | "What if there was a better way?" |

Music & Audio

Background Music Guidelines

• Volume: 20-30% under narration (duck 6-12dB when voice plays)
• Style: match the brand tone (corporate = ambient electronic, startup = upbeat indie)
• Structure: intro swell (first 3s) -> subtle loop under narration -> swell at CTA
• No vocals: instrumental only under narration

# Generate background music
belt app run <music-gen-app> --input '{
  "prompt": "upbeat corporate background music, modern electronic, 90 BPM, positive and professional, no vocals, suitable for product explainer video"
}'

Assembly Pipeline

Full Production Workflow

# 1. Generate voiceover
belt app run falai/dia-tts --input '{
  "prompt": "[S1] Your script here..."
}'

# 2. Generate scene visuals (in parallel)
belt app run google/veo-3-1-fast --input '{"prompt": "scene 1 description"}' --no-wait
belt app run google/veo-3-1-fast --input '{"prompt": "scene 2 description"}' --no-wait
belt app run google/veo-3-1-fast --input '{"prompt": "scene 3 description"}' --no-wait

# 3. Merge scenes into sequence
belt app run infsh/media-merger --input '{
  "media": ["scene1.mp4", "scene2.mp4", "scene3.mp4"]
}'

# 4. Add voiceover to video
belt app run infsh/video-audio-merger --input '{
  "video": "merged-scenes.mp4",
  "audio": "voiceover.mp3"
}'

# 5. Add captions
belt app run infsh/caption-videos --input '{
  "video": "final-with-audio.mp4",
  "caption_file": "captions.srt"
}'

Video Length by Format

| Format | Length | Platform | |--------|--------|----------| | Social teaser | 15-30s | TikTok, Instagram Reels, YouTube Shorts | | Product demo | 60-90s | Website, landing page | | Feature explainer | 90-120s | YouTube, email | | Tutorial/walkthrough | 2-5min | YouTube, help center | | Investor pitch video | 2-3min | Pitch deck supplement |

Transition Types

| Transition | When to Use | Effect | |------------|-------------|--------| | Cut | Default between related scenes | Clean, professional | | Dissolve/Crossfade | Time passing, mood shift | Soft, contemplative | | Wipe | New topic or section | Clear separation | | Zoom/Push | Drilling into detail | Focus attention | | Match cut | Visual similarity between scenes | Clever, memorable |

Common Mistakes

| Mistake | Problem | Fix | |---------|---------|-----| | Script too wordy | Voiceover rushed, viewer overwhelmed | Cut to 150 wpm max | | No hook in first 3s | Viewers leave immediately | Start with the problem or surprising stat | | Visuals lag narration | Confusing disconnect | Visuals should match or slightly precede words | | Background music too loud | Can't hear narration | Duck music 6-12dB under voice | | No captions | 85% of social video watched silent | Always add captions | | Too many ideas | Viewer retains nothing | One core message per video |

Related Skills

npx skills add inference-sh/skills@ai-video-generation
npx skills add inference-sh/skills@video-prompting-guide
npx skills add inference-sh/skills@text-to-speech
npx skills add inference-sh/skills@prompt-engineering

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