---
title: "Segment Mask"
description: "Track an object through a video from a text prompt (Meta SAM 3) and get back a black and white mask video: white where the object is, black everywhere else. The prompt defaults to `face`; separate several objects with commas (`face, hands`). Clips up to 1800 frames (30 seconds at 60 fps, 15 seconds at 120 fps) as a regular MP4 or MOV. Charged up front for the counted frames; the hold is normally refunded down to the frames in the returned mask."
updated: 2026-10-03
---

# Segment Mask

**Node type:** `process:video_segment_mask`  
**Category:** `process`

## Description

Track an object through a video from a text prompt (Meta SAM 3) and get back a black and white mask video: white where the object is, black everywhere else. The prompt defaults to `face`; separate several objects with commas (`face, hands`). Clips up to 1800 frames (30 seconds at 60 fps, 15 seconds at 120 fps) as a regular MP4 or MOV. Charged up front for the counted frames; the hold is normally refunded down to the frames in the returned mask.

## Pricing

- **Cost:** ~4 credits per seconds
- **Per-second rate:** The figure is the rate at a 5-second reference run. Our margin is progressive and steepest on the smallest runs, so a clip shorter than that can cost more per second, and a model priced with a flat multiplier is exact at every length. The charge is always computed from the real duration.
- **Notes:** fal bills $0.005 per 16 frames of the input. Clips are limited to 1800 frames (30 seconds at 60 fps, 15 seconds at 120 fps), counted from the file before the run; a longer clip, a fragmented MP4, a file joined from several clips without re-muxing, or one whose frames cannot be counted is refused before you are charged. The run is charged up front for the counted frames at the 60 fps rate, then normally refunded down to the frames in the mask fal returns, counted from that file. A 24 or 30 fps clip ends up paying for its own frames.

## Canvas ports

These appear as port handles on the left side of the node.

| ID          | Label      | Details                                                                                                          |
| ----------- | ---------- | ---------------------------------------------------------------------------------------------------------------- |
| `video_url` | **Video**  | `VIDEO` _(required)_                                                                                             |
| `prompt`    | **Prompt** | `TEXT` — What to mask. Defaults to `face`. Separate several objects with commas, e.g. `face, hands` or `person`. |

## Sidebar config

These render as form fields in the right-side config panel when the node is selected.

| ID                    | Label                   | Details                                                                                       |
| --------------------- | ----------------------- | --------------------------------------------------------------------------------------------- |
| `detection_threshold` | **Detection Threshold** | `NUMBER` · `0.1…1` — Lower finds more (and less precise) matches, higher only confident ones. |

## Outputs

| ID      | Label          | Type    |
| ------- | -------------- | ------- |
| `video` | **Mask Video** | `VIDEO` |

## What comes out

A black and white video the same size and length as the clip: white where the prompt matched, black everywhere else. It is the mask itself, not your clip with a colored overlay. Track several things at once by separating them with commas (`face, hands`), or use `person` for the whole body. If a small or turned face is missed, lower **Detection Threshold**; if it grabs things it should not, raise it.

## What it is not, yet

It does not hide anything on its own. Laying the mask over the clip with Video Blend changes the colors of the whole frame (see the note on [Video Blend](/docs/nodes/process--video_blend)), so it is not a clean face hide. A masked merge that keeps the rest of the frame untouched is not shipped yet.

---

_Auto-generated from the Wireflow node registry._

---

Documentation index: fetch https://www.wireflow.ai/llms.txt for the full list of Wireflow docs.