Comfy-Org/ComfyUI · error · ValueError

Either first_frame or first_frame_asset_id is required.

Error message

Either first_frame or first_frame_asset_id is required.

What it means

The keyframe Seedance node requires a first frame to anchor the generation; neither the first_frame image input nor the first_frame_asset_id string was provided. Unlike the general reference node, this i2v-style path cannot run text-only, so the node fails fast before uploading or polling anything.

Source

Thrown at comfy_api_nodes/nodes_bytedance.py:2501

        cls,
        model: dict,
        seed: int,
        watermark: bool,
        first_frame: Input.Image | None = None,
        last_frame: Input.Image | None = None,
        first_frame_asset_id: str = "",
        last_frame_asset_id: str = "",
    ) -> IO.NodeOutput:
        validate_string(model["prompt"], strip_whitespace=True, min_length=1)
        model_id = SEEDANCE_MODELS[model["model"]]

        first_frame_asset_id = first_frame_asset_id.strip()
        last_frame_asset_id = last_frame_asset_id.strip()

        if first_frame is not None and first_frame_asset_id:
            raise ValueError("Provide only one of first_frame or first_frame_asset_id, not both.")
        if first_frame is None and not first_frame_asset_id:
            raise ValueError("Either first_frame or first_frame_asset_id is required.")
        if last_frame is not None and last_frame_asset_id:
            raise ValueError("Provide only one of last_frame or last_frame_asset_id, not both.")

        if model_id == "dreamina-seedance-2-5-260628":
            # 2.5 accepts ratio="adaptive" only here and keeps the first frame's own aspect
            # (a 1920x1088 frame yields 850x482, not a grid ratio), so pre-sizing the frames to a
            # supported pixel pair would crop framing the model would otherwise have preserved.
            request_ratio = "adaptive"
            if first_frame is not None:
                first_frame = _prepare_seedance_image(first_frame)
            if last_frame is not None:
                last_frame = _prepare_seedance_image(last_frame)
        elif first_frame_asset_id or last_frame_asset_id:
            request_ratio = model["ratio"]
            if first_frame is not None:
                first_frame = _prepare_seedance_image(first_frame)
            if last_frame is not None:
                last_frame = _prepare_seedance_image(last_frame)

View on GitHub (pinned to 1c6d8d45b3)

Solutions

1. Connect an image to first_frame.
2. Or paste a valid uploaded asset id into first_frame_asset_id (from the asset upload node's output).

if first_frame is None and not first_frame_asset_id.strip():
    raise ValueError("first frame required: wire first_frame or set first_frame_asset_id")

When it happens

Trigger: Calling the first/last-frame node with first_frame left unwired and an empty/whitespace first_frame_asset_id string.

Common situations: Converting a t2v workflow to the keyframe node without wiring the frame; asset id typo that strips to empty; partially copied node configs.

Related errors

• At least one reference image or video or asset is required.
• Provide only one of first_frame or first_frame_asset_id, not
• Provide only one of last_frame or last_frame_asset_id, not b
• Asset {aid} is not an Image asset.
• Too many reference images: {total_images} (images={len(refer

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/a291311f091e6610. Report an issue: GitHub.