Thumbnail

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

Inputs

Reads upstream consistency is_complete to skip incomplete videos

Output keys

thumbnail_flag (String), thumbnail_path (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

ThumbnailNodeOptions control the contact-sheet layout:

Option Meaning

tileSize

Pixel size of each frame tile

cols

Number of columns in the grid

rows

Number of rows in the grid

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.