Thumbnail

A contact sheet of a video, so the interface has something to show.

The thumbnail node generates a contact-sheet preview (a tiled grid of frames) for a video, giving the UI a fast visual summary of the content.

Kind

thumbnail

Applies to

Video only

Input ports

media, plus an optional is_complete — connect Consistency's is_complete port to skip incomplete videos

Output ports

thumbnail (the contact sheet, the file S3 Sink uploads), flag (String)

Requirements

OpenCV / video4j native runtime (frame extraction). CPU-bound. Storage: the generated image is written to the worker’s local thumbnail cache (a durable .thumb file); only a ledger entry goes to Loom.

Persists to

asset_node_result ledger (image bytes stay in the local cache)

Configuration

The Thumbnail Generator settings panel: Grid Columns

Figure 1. The node’s settings in the pipeline editor

These settings control the contact-sheet layout. Set them in the panel above, or in the node’s options block in a pipeline definition:

Option Meaning

Option	Meaning
`tileSize`	Pixel size of each frame tile
`cols`	Number of columns in the grid
`rows`	Number of rows in the grid

tileSize

Pixel size of each frame tile

cols

Number of columns in the grid

rows

Number of rows in the grid

Seeing it run

Turn on Debug Mode and every node keeps what it produced, on the card itself. Below is a real run of this node over pexels-jack-sparrow-5977265.mp4.

The strip on the card lists what each output port carried — flag, thumbnail.

Selecting one of them opens it full size.

One output of the thumbnail node opened full size

Use Cases

Fast browsing — show a visual overview of a video without opening it.
Preview generation — produce a poster/scrubbing sheet for the asset detail view.

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