> ## Documentation Index
> Fetch the complete documentation index at: https://docs.comfy.org/llms.txt
> Use this file to discover all available pages before exploring further.

# SAM3_TrackPreview - ComfyUI Built-in Node Documentation

> Documentation for SAM3TrackPreview node.

## Overview

This node creates a video preview of tracked objects, drawing each tracked object with a distinct color overlay and a number label. It does not output any image or video tensors — instead, it saves the resulting preview video directly to a temporary file.

## Inputs

| Parameter | Description | Data Type | Required | Range |
| - | - | - | - | - |
| `track_data` | The tracking data containing packed masks and object information from a SAM3 tracking node. | TRACK\_DATA | Yes | - |
| `images` | Optional input images to use as the background for the preview. If not provided, a black background is used. | IMAGE | No | - |
| `opacity` | The opacity of the color overlay applied to tracked objects (default: 0.5). | FLOAT | No | 0.0 to 1.0 (step: 0.05) |
| `fps` | The frame rate of the output video (default: 24.0). | FLOAT | No | 1.0 to 120.0 (step: 1.0) |

## Outputs

| Output Name | Description | Data Type |
| - | - | - |
| `ui` | A UI element that displays the generated preview video. No tensor data is returned. | PREVIEW\_VIDEO |

> This documentation was AI-generated. If you find any errors or have suggestions for improvement, please feel free to contribute! [Edit on GitHub](https://github.com/Comfy-Org/embedded-docs/blob/main/comfyui_embedded_docs/docs/SAM3_TrackPreview/en.md)

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