---
title: "thumbnail · RUAL Documentation"
description: "Extracts a single frame from a video as a JPEG poster image. Runs inline : it decodes one frame, not the whole file."
canonical: https://docs.rual.nl/block-types/video/video_thumbnail
language: en
---

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[Troubleshooting](https://docs.rual.nl/troubleshooting)

Other

# thumbnail

This block is part of the [`video`](https://docs.rual.nl/block-types/video) group and was last modified in core [`v15.0.0`](https://docs.rual.nl/core-versions/150000).

Extracts a single frame from a video as a JPEG poster image. Runs inline : it decodes one frame, not the whole file.

- flow `flow`

- file required `value` Video file. Accepts a file object (from another file block) or a relative path string.

- output file `value` Output path for the .jpg, relative to the entity root : e.g. `public/clips/thumb123.jpg`. When empty, a hash-named .jpg is written alongside the input.

- at (s) `number` Timestamp to grab, in seconds. When it lands past the end of the video the midpoint is used instead, so a short clip still gets a picture.

Default `1`

- max size `number` Longest-side cap in pixels. Set to 0 to keep the source size.

Default `640`

- quality `number` JPEG quality on ffmpeg's scale: 2 is best, 31 is worst. Values outside that range fall back to 3.

Default `3`

- flow `flow`

- success `condition`

- output file `value` Path the JPEG was written to, relative to the entity root : feed it to `get link` or store it directly.

- width `number` Width of the written thumbnail.

- height `number` Height of the written thumbnail.

- error `value`

| `poster frame` |
| --- |
| `video still` |
| `screenshot` |
| `video thumbnail` |

A typical wiring for [thumbnail](https://docs.rual.nl/block-types/video/video_thumbnail): a [function trigger](https://docs.rual.nl/block-types/globals/trigger_custom_function) starts the flow; [value](https://docs.rual.nl/block-types/value/value_default) feeds the `file` pin; the `flow` out pin feeds [debug](https://docs.rual.nl/block-types/state%2520ui/state_debug).

[![Studio canvas example for the thumbnail block: typical wiring for thumbnail.](https://docs.rual.nl/canvas-examples/video_thumbnail.png)](https://docs.rual.nl/canvas-examples/video_thumbnail.png?v=3)

## Used in these guides

These documentation pages use or explain this block:

- [Assets](https://docs.rual.nl/blueprints/assets)

## Version history

Introduced in [`v15.0.0`](https://docs.rual.nl/core-versions/150000).

- [Back to `video`](https://docs.rual.nl/block-types/video): Return to the main group to view all sub-groups

- [Back to `video`](https://docs.rual.nl/block-types/video?group=video): Return to the group to view all blocks within this group

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