Comfy-Org/ComfyUI · error · ValueError

Keyframe times must be finite numbers in seconds; got '{valu

Error message

Keyframe times must be finite numbers in seconds; got '{value}'.

What it means

Keyframe times must be finite floats; math.isfinite rejects nan and inf. These would otherwise pass float() parsing but make clip timing undefined, so they are rejected explicitly.

Source

Thrown at comfy_api_nodes/nodes_bfl.py:1068

        raise ValueError(f"FLUX 3 supports at most {_FLUX3_MAX_IMAGES} {field_name}, got {len(flat)}.")
    for tensor in flat:
        _flux3_validate_image(tensor)
    return flat


def _flux3_parse_times(value: str, image_count: int, duration: int | str) -> list[float]:
    """Parse one keyframe time in seconds per image: increasing, inside the clip."""
    parts = [part.strip() for part in value.split(",") if part.strip()]
    if len(parts) != image_count:
        raise ValueError(
            f"Give one time per keyframe image: got {len(parts)} time(s) for {image_count} image(s)."
        )
    try:
        times = [float(part) for part in parts]
    except ValueError as exc:
        raise ValueError(f"Keyframe times must be numbers in seconds, comma-separated; got '{value}'.") from exc
    if not all(math.isfinite(time) for time in times):
        raise ValueError(f"Keyframe times must be finite numbers in seconds; got '{value}'.")
    if any(later <= earlier for earlier, later in zip(times, times[1:])):
        raise ValueError(f"Keyframe times must increase; got {times}.")
    if times[0] < 0:
        raise ValueError(f"Keyframe times cannot be negative; got {times[0]}.")
    cap = _FLUX3_MAX_DURATION if duration == "auto" else int(duration)
    if times[-1] > cap:
        raise ValueError(f"Keyframe time {times[-1]}s is past the end of a {cap}s clip.")
    return times


class Flux3VideoNodeBase(IO.ComfyNode):
    """Shared widgets, request plumbing and polling for the FLUX 3 generation modes."""

    RATE_HD: float
    RATE_FHD: float

    @classmethod
    def common_inputs(cls) -> list:

View on GitHub (pinned to 1c6d8d45b3)

Solutions

Sanitize computed times: skip or clamp non-finite values before formatting the string.
Guard divisions: t = a / b if b else 0.0.
Validate with math.isfinite before wiring the value in.

Example fix

# before
times = [t / duration for t in offsets]  # duration=0 -> inf -> ValueError

# after
times = [t / duration if duration else 0.0 for t in offsets]
times = [min(t, cap) if math.isfinite(t) else 0.0 for t in times]

Defensive patterns

Strategy: validation

Validate before calling

import math
times = [float(p) for p in value.split(",")]
assert all(math.isfinite(t) for t in times), "non-finite keyframe time"

Type guard

def times_finite(value: str) -> bool:
    import math
    try:
        return all(math.isfinite(float(p)) for p in value.split(","))
    except ValueError:
        return False

Prevention

Guard divisions used to compute times.
Clamp or replace non-finite values before formatting.
Check math.isfinite on computed offsets.

When it happens

Trigger: Passing 'nan', 'inf', '-inf', or arithmetic that evaluates to them (e.g. division by zero when building the string programmatically) in the keyframe times string.

Common situations: Computing times from user parameters where a zero duration divides to inf; string-building bugs producing 'nan'.

Related errors

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/a90e2ff12c26ada5. Report an issue: GitHub.