Skill Runway Video Gen

Generate short product videos from images using Runway Gen4 Turbo. Use for TikTok ads, UGC-style product demos, Reels, and YouTube Shorts.

Wraps Runway Gen4 Turbo image-to-video API. Point at a product image, describe the motion, get an MP4. No browser needed.

Usage

uv run scripts/generate_video.py \
  --image product.jpg \
  --prompt "water droplets falling, soft bokeh, slow motion" \
  --output output.mp4 \
  --duration 10 \
  --ratio 720:1280

Args

Arg	Default	Description
--image	required	Path to source product image
--prompt	""	Motion description (optional but recommended)
--output	required	Output MP4 path
--duration	10	Video length: 5 or 10 seconds
--ratio	720:1280	Aspect ratio (vertical for TikTok)

Config

API key is read from (in order):

1. RUNWAY_API_KEY environment variable
2. ~/tiktok-api.json → runway.apiKey

Cost

Duration	Cost
5s	$0.25
10s	$0.50

Always use 10s — you get more content to work with.

Known quirks

Last 1–2s often freezes. Fix: stretch to 12s at 0.83x speed using MoviePy:

from moviepy import VideoFileClip
clip = VideoFileClip("output.mp4")
slow = clip.with_effects([vfx.MultiplySpeed(0.83)])
slow.write_videofile("output_12s.mp4", fps=30)

Rate limits

No per-minute quota (unlike Veo). Runway charges per second of output.

Pipeline integration

This skill feeds into skill-tiktok-video-pipeline as the video generation step. The pipeline handles slowmo stretch and caption overlay automatically.