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

Before-After-Bridge (BAB) — 90 seconds

Feature Spotlight — 30 seconds (social)

Pacing Rules

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

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_files": [
    {"file": "scene1.mp4", "transition_type": "crossfade"},
    {"file": "scene2.mp4", "transition_type": "crossfade"},
    {"file": "scene3.mp4"}
  ]
}'

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

# 5. Add captions (segments are timed text, not an SRT file)
belt app run infsh/caption-videos --input '{
  "video_file": "final-with-audio.mp4",
  "segments": [
    {"start": 0.0, "end": 2.5, "text": "First caption line"},
    {"start": 2.5, "end": 5.0, "text": "Second caption line"}
  ]
}'

Video Length by Format

Transition Types

Common Mistakes

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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