rw-generate-video
Generate videos directly using the Runway API via runnable scripts. Supports text-to-video, image-to-video, and video-to-video with seedance2, gen4.5, veo3, and more.

Generate Video

Generate videos directly using the Runway API. This skill runs Python scripts that call the API, poll for completion, and download the result.

IMPORTANT: Run scripts from the user's working directory so output files are saved where the user expects.

Usage

uv run scripts/generate_video.py --prompt "your description" --filename "output.mp4" [--model seedance2] [--ratio 1280:720] [--duration 5] [--image-url "..."]

Preflight

  1. command -v uv must succeed. If not, tell the user to install uv: curl -LsSf https://astral.sh/uv/install.sh | sh
  2. RUNWAYML_API_SECRET must be set in the environment. Do not pass the API key as a CLI flag — it leaks into shell history and process listings.

Security Notes

Available Models

Model Best For Input Cost
seedance2 Reference image and video, long duration (up to 15s) Text, Image, and/or Video 36 credits/sec
gen4.5 High quality, general purpose Text and/or Image 12 credits/sec
gen4_turbo Fast, image-driven Image required 5 credits/sec
gen4_aleph Video editing/transformation Video + Text/Image 15 credits/sec
veo3 Premium quality Text/Image 40 credits/sec
veo3.1 High quality Google model Text/Image 20-40 credits/sec
veo3.1_fast Fast Google model Text/Image 10-15 credits/sec

Model Selection Guidance

Map user requests: - "product ad", "e-commerce", "long video" -> seedance2 - "fast", "cheap", "quick" -> veo3.1_fast or gen4_turbo (if they have an image) - "high quality", "best", "cinematic" -> gen4.5 or veo3 - "edit video", "transform video" -> gen4_aleph or seedance2 - No preference -> seedance2

Parameters

Param Description Default
--prompt Text description (required) --
--filename Output filename (required) --
--model Video model gen4.5
--ratio Aspect ratio (pixel-based). Common: 1280:720, 720:1280, 960:960. seedance2 also supports 1112:834, 834:1112, 1470:630, etc. 1280:720
--duration Duration in seconds (model-dependent, seedance2 supports up to 15s) 5
--image-url Image URL or local file for image-to-video --
--video-url Video URL or local file for video-to-video (gen4_aleph, seedance2) --
--output-dir Output directory cwd

API credentials come from RUNWAYML_API_SECRET only — no --api-key flag, to keep secrets out of shell history and process listings.

Filename Convention

Generate filenames with the pattern: yyyy-mm-dd-hh-mm-ss-name.mp4

Examples: - "A cyberpunk city" -> 2026-04-14-14-23-05-cyberpunk-city.mp4 - "Waves on a beach" -> 2026-04-14-15-30-12-beach-waves.mp4

Examples

Text-to-video (seedance2):

uv run scripts/generate_video.py --prompt "A serene mountain landscape at sunrise with mist" --filename "2026-04-14-mountain-sunrise.mp4" --model seedance2 --ratio 1280:720

Image-to-video (animate a local product photo):

uv run scripts/generate_video.py --prompt "Camera slowly zooms out, product sparkles" --image-url "./product.jpg" --filename "2026-04-14-product-reveal.mp4" --model seedance2 --ratio 720:1280

Video-to-video from a local file (seedance2):

uv run scripts/generate_video.py --prompt "Transform into a warm golden sunset scene" --video-url "./input.mp4" --filename "2026-04-14-sunset-transform.mp4" --model seedance2

Fast draft:

uv run scripts/generate_video.py --prompt "A cat playing piano" --filename "draft.mp4" --model veo3.1_fast --ratio 1280:720 --duration 4

Premium quality:

uv run scripts/generate_video.py --prompt "Cinematic drone shot over Tokyo at night" --filename "tokyo.mp4" --model veo3 --ratio 1280:720 --duration 8

Output

Common Failures

For Batch Generation

To generate many videos at once, run this script in a loop — the agent can orchestrate multiple calls with different prompts, images, or parameters to produce campaigns, localized variants, or creative iterations at scale.