Video Extension Specification

• Title: Video
• Identifier: https://stac-extensions.github.io/video/v1.0.0/schema.json
• Field Name Prefix: video
• Scope: Item, Collection
• Extension Maturity Classification: Proposal
• Owner: @darrenwiens

This document explains the Video Extension to the SpatioTemporal Asset Catalog (STAC) specification.

The motivation behind this extension is to provide a standardized way to include various video sources within STAC Items.

• Examples:
  • Item example: Shows the basic usage of the extension in a STAC Item
  • Collection example: Shows the basic usage of the extension in a STAC Collection
• JSON Schema
• Changelog

Item Properties

Field Name	Type	Description
video:shape	[integer]	REQUIRED. Pixel dimensions of video, expressed as [rows, columns]
video:frame_rate	number	The mean frame rate, frames per second (frame count / time extent). Either video:frame_rate or video:frame_count are highly recommended.
video:frame_count	integer	The count of frames in the video. Either video:frame_rate or video:frame_count are highly recommended.
video:codec_name	string	Four-letter codec code (list)
video:constant_scene	boolean	Flag indicating that both the frame geometries and sensor centers remain constant throughout the video. Default is false.
video:letterbox	[integer]	Rectangular window containing useful (non-fill) pixel values, if different from video:shape, in the form [columns_offset, rows_offset, width, height]
video:sensor_name	string	Image source sensor name (corresponds to MISB ST 0601.17.11)
video:miis_core_id	string	MIIS core identifier (corresponds to MISB ST 0601.17.94)

Assets

Video assets should be differentiated by asset roles. Assets may be named arbitrarily and must be unique, but it is recommended to group associated assets with a common asset role (e.g. "group:video1")

Asset Roles	Description
["data", "video", "group:groupname"]	Video asset.
["metadata", "video:frame_geometries", "group:groupname"]	Asset containing polygon geometry(s) representing the corners of video frames. This should be a feature collection containing: 1 polygon if video:constant_scene=true, or n polygons, where n=video:frame_count if video:constant_scene=false.
["metadata", "video:frame_centers", "group:groupname"]	Asset containing point geometry(s) representing the center of video frames. This should be a feature collection containing: 1 point if video:constant_scene=true, or n points, where n=video:frame_count if video:constant_scene=false.
["metadata", "video:sensor_centers", "group:groupname"]	Asset containing point geometry(s) representing the location of the sensor. This should be a feature collection containing: 1 point if video:constant_scene=true, or n points, where n=video:frame_count if video:constant_scene=false

Contributing

All contributions are subject to the STAC Specification Code of Conduct. For contributions, please follow the STAC specification contributing guide Instructions for running tests are copied here for convenience.

Running tests

The same checks that run as checks on PR's are part of the repository and can be run locally to verify that changes are valid. To run tests locally, you'll need npm, which is a standard part of any node.js installation.

First you'll need to install everything with npm once. Just navigate to the root of this repository and on your command line run:

npm install

Then to check markdown formatting and test the examples against the JSON schema, you can run:

npm test

This will spit out the same texts that you see online, and you can then go and fix your markdown or examples.

If the tests reveal formatting problems with the examples, you can fix them with:

npm run format-examples