An engine turns the script into a vertical 1080×1920 video. Remotion is the default. You can pick another one for a single run, for a series, or for the whole machine.

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The engines

Every ready engine follows the length of the voice and burns an AI-GENERATED chip into the picture. By default an engine draws the plain template. An agent can instead design the picture for each video. See Scenes. A scene needs vfrey-framey or hyperframes for HTML, or remotion for React. npx vfrey engine list shows each engine as ready or unavailable, with the reason, and marks the default. npx vfrey doctor shows the same in its engines check.

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Choose an engine

The most specific choice wins.
  1. --engine ID on tick or render. It applies to that run only.
  2. The series engine. Use the Engine select on the dashboard, or npx vfrey desk series update --id ID --engine ENGINE_ID. Pass --engine default to follow the project or machine default again.
  3. The project’s engine, the engine field in vfrey.json. Set it with npx vfrey init --engine ENGINE_ID. The summary says (from vfrey.json) when it decided.
  4. The machine default: npx vfrey engine use ENGINE_ID.
  5. Remotion, when nothing else is set.

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What the run reports

The engine that rendered the video appears in the Engine: line of the tick summary, in tick --json, on the run page of the dashboard, and in doctor.

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When an engine cannot run

If the engine you chose is unavailable or fails, the job ends blocked. The message ends with a Fix: line that names an engine that is ready. There is no silent fallback, so vfrey never renders with a different engine than the one you chose.
To compare engines, run the same --script once for each engine.

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For agents

  • Pass --engine only when the person names an engine. Otherwise leave it out.
  • Always say which engine rendered the video. Read the Engine: line, or jobs[].engine in --json.
  • If a run is blocked with a Fix: line, relay it and let the person choose. Do not switch engines quietly.

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Troubleshooting

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Framey shows unavailable

vfrey Framey uses the Chrome Headless Shell that Remotion downloads. Until it is cached, Framey shows unavailable. Run:
A first Remotion render also downloads it. Then run npx vfrey engine list again.

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HyperFrames shows unavailable

Install the upstream hyperframes CLI, or choose another engine. npx vfrey engine list gives the reason.

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ComfyUI shows unavailable

ComfyUI is not wired yet. Choose another engine.