Comfy-Org/ComfyUI · error · ValueError

Runway task succeeded but no video data found in response.

Error message

Runway task succeeded but no video data found in response.

What it means

Raised after a Runway image-to-video task reaches a terminal state but the polled response contains an empty `output` field. The submission and polling both succeeded (get_response returned), so this indicates a malformed or unexpected server response rather than a request failure. The node refuses to proceed because there is no video URL to download.

Source

Thrown at comfy_api_nodes/nodes_runway.py:136

        progress_extractor=lambda r: r.progress * 100 if r.progress is not None else None,
    )


async def generate_video(
    cls: type[IO.ComfyNode],
    request: RunwayImageToVideoRequest,
    estimated_duration: int | None = None,
) -> InputImpl.VideoFromFile:
    initial_response = await sync_op(
        cls,
        endpoint=ApiEndpoint(path=PATH_IMAGE_TO_VIDEO, method="POST"),
        response_model=RunwayImageToVideoResponse,
        data=request,
    )

    final_response = await get_response(cls, initial_response.id, estimated_duration)
    if not final_response.output:
        raise ValueError("Runway task succeeded but no video data found in response.")

    video_url = get_video_url_from_task_status(final_response)
    return await download_url_to_video_output(video_url)


class RunwayImageToVideoNodeGen3a(IO.ComfyNode):

    @classmethod
    def define_schema(cls):
        return IO.Schema(
            node_id="RunwayImageToVideoNodeGen3a",
            display_name="Runway Image to Video (Gen3a Turbo)",
            category="partner/video/Runway",
            description="Generate a video from a single starting frame using Gen3a Turbo model. "
            "Before diving in, review these best practices to ensure that "
            "your input selections will set your generation up for success: "
            "https://help.runwayml.com/hc/en-us/articles/33927968552339-Creating-with-Act-One-on-Gen-3-Alpha-and-Turbo.",
            inputs=[

View on GitHub (pinned to 1c6d8d45b3)

Solutions

1. Retry the generation — transient server-side output omission usually resolves on rerun
2. Check the Runway service status / API changelog for response-schema changes
3. Inspect the raw task JSON via the Runway dashboard for the same task id to confirm whether output was produced

for attempt in range(2):
    try:
        return await generate_video(cls, request)
    except ValueError as e:
        if "no video data found" in str(e) and attempt == 0:
            continue
        raise

When it happens

Trigger: Calling RunwayImageToVideo via generate_video(); initial POST succeeds, polling completes, but final_response.output is falsy (empty list, None, or missing key in the JSON body).

Common situations: Runway API behavior changes or partial responses; task marked succeeded server-side while output artifacts were not attached; rare transient server-side serialization issues.

Related errors

• Runway task succeeded but no image data found in response.
• sync.so generation completed but no output URL was returned.
• Gemini did not generate a video. Model response: {model_mess
• Gemini did not generate a video. Try rephrasing your prompt,
• Gemini interaction did not complete (status: {interaction.st

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/af9882f13701ba78. Report an issue: GitHub.