viral-video-generator

name

viral-video-generator

description

End-to-end AI video production pipeline. Generate complete vertical videos (Instagram Reels, TikTok, YouTube Shorts) from a text prompt. Combines AI video clip generation (Google Veo 3.1), neural text-to-speech (Piper TTS), synthesized background music, sound effects, and ffmpeg assembly. Use when the user asks to create a video, make a reel, produce a short, generate video content, make a meme video, create a promo video, or build any short-form vertical video.

Viral Video Generator

End-to-end pipeline for producing short-form vertical videos from a text prompt.

Pipeline Overview

Prompt -> Script -> [Parallel Generation] -> Assembly -> Final Video
                    ├── Video Clips (Veo 3.1)
                    ├── Voiceover (Piper TTS)
                    └── Music + SFX (ffmpeg synthesis)

Quick Start

# Generate a complete video
python3 ~/.claude/skills/viral-video-generator/scripts/generate_video.py \
  --prompt "A capybara uses AI to build a dating website" \
  --style meme \
  --output ./outputs/my-video.mp4

Or orchestrate manually with individual scripts (see Workflow below).

Requirements

Auto-installed on first run:

• Piper TTS: pip install piper-tts pathvalidate --break-system-packages
• Piper voice model: Downloaded to /tmp/piper-voices/en_US-amy-medium.onnx
• ffmpeg: Static build at /tmp/ffmpeg-7.0.2-amd64-static/ffmpeg

Required:

• AI_GATEWAY_API_KEY environment variable (for video generation via Veo 3.1)
• generate-video skill installed at ~/.claude/skills/generate-video/

Workflow

Step 1: Write Script

Use the script template in references/script-templates.md. Every video follows the 6-8 scene structure:

Scene	Purpose	Duration
Hook	Grab attention, relatable problem	5-9s
Discovery	Introduce the solution	6-10s
Demo	Show it working	8-13s
Features	Key benefits (1-3 scenes)	5-10s each
Payoff	Emotional resolution	6-8s
CTA	Call to action	5-9s

Write each scene with:

• visual_prompt: Text prompt for AI video generation
• voiceover: Narration text
• sfx: Sound effect cue (whoosh, ding, boom, etc.)

Step 2: Generate Assets (Parallel)

Launch all three in parallel for speed:

2a. Video Clips

# For each scene:
node ~/.claude/skills/generate-video/scripts/generate_video_sdk.js \
  "VISUAL_PROMPT" \
  --model "google/veo-3.1-fast-generate-preview" \
  --duration 5 --aspect-ratio "9:16" \
  --output scene-N.mp4 --timeout 300

Fallback models: google/veo-3.1-generate-preview, seedance/seedance-1-5-pro-i2v

For real website/product shots, use Ken Burns effect on screenshots:

$FFMPEG -y -loop 1 -i screenshot.jpg -t $DURATION \
  -vf "scale=2160:3840,zoompan=z='min(zoom+0.001,1.3)':x='iw/2-(iw/zoom/2)':y='ih/3-(ih/zoom/3)':d=$FRAMES:s=1080x1920:fps=30,format=yuv420p" \
  -c:v libx264 -preset fast -crf 23 output.mp4

YouTube thumbnails: curl -sL "https://img.youtube.com/vi/VIDEO_ID/maxresdefault.jpg"

2b. Voiceover (Piper TTS)

# Install if needed
bash ~/.claude/skills/viral-video-generator/scripts/setup_tts.sh

# Generate per-scene voiceover
echo "VOICEOVER TEXT" | /home/node/.local/bin/piper \
  --model /tmp/piper-voices/en_US-amy-medium.onnx \
  --output_file scene-N-vo.wav \
  --length_scale 1.0 --sentence_silence 0.3

# Concatenate all scenes with silence gaps using Python
python3 ~/.claude/skills/viral-video-generator/scripts/concat_audio.py \
  scene1-vo.wav scene2-vo.wav ... --silence 0.4 --output voiceover-full.wav

2c. Background Music + SFX

bash ~/.claude/skills/viral-video-generator/scripts/generate_music.sh \
  --style upbeat --duration 60 --bpm 130 \
  --output-dir ./assets/audio/

Styles: upbeat (130 BPM), romantic (100 BPM), epic (140 BPM), chill (90 BPM)

Generates: background-music.wav, whoosh.wav, boom.wav, ding.wav, record-scratch.wav

Step 3: Normalize Video Clips

Extend/loop each clip to match its voiceover duration:

python3 ~/.claude/skills/viral-video-generator/scripts/normalize_clips.py \
  --clips-dir ./assets/video-clips/ \
  --audio-dir ./assets/audio/ \
  --scene-map scene-map.json \
  --output-dir ./normalized/

Step 4: Assemble Final Video

python3 ~/.claude/skills/viral-video-generator/scripts/assemble_video.py \
  --video-dir ./normalized/ \
  --voiceover ./assets/audio/voiceover-full.wav \
  --music ./assets/audio/background-music.wav \
  --sfx-dir ./assets/audio/ \
  --scene-map scene-map.json \
  --output ./output/final.mp4

Assembly pipeline:

1. Iterative xfade merge (fade/slideright/slideup transitions, 0.3s)
2. Mix voiceover (vol 1.3) + music (vol 0.12) + SFX with amix + alimiter
3. Combine video + audio with AAC 192kbps
4. Apply movflags +faststart for web playback

Output Specs

Property	Value
Resolution	1080x1920 (9:16 vertical)
Video codec	H.264 (libx264)
Frame rate	30 fps
Audio codec	AAC 192kbps, 44.1kHz
Format	MP4 with faststart

Scene Map Format

{
  "scenes": [
    {
      "id": 1,
      "clip": "scene1-hook.mp4",
      "voiceover": "scene1-vo.wav",
      "vo_text": "This is Gerald. Gerald is a capybara.",
      "visual_prompt": "A cute lonely capybara by a sunset pond",
      "transition": "fade",
      "sfx": [{"type": "whoosh", "offset": 0}]
    }
  ]
}

Tips for Viral Content

• Hook in 2 seconds: First scene must grab attention immediately
• Short sentences: Punchy narration. Comedic pauses. Dry humor.
• Relatable problems: Start with pain points the audience knows
• Show, don't tell: Visual storytelling over text walls
• Emotional payoff: End with a feel-good moment before CTA
• Under 60s for Reels: Instagram favors 30-60s; TikTok up to 90s