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Published

pixel aspect ratio

vr.tr.pixel-aspect-ratio · thing-q588886

Let an agent explain pixel aspect ratio and its relation to display and storage aspect ratios, identify the ratios used by video standards, support correct conversion and display, and support learning in video technology.

Thing Registry Cross-cutting context XCT.REL
Bundle → Layer → Finding → QuestionsClassifiersWhat it isWhy it existsDistinguishing featuresWhat robots and AI may and may not doMoral aspectsOwnersLinks to other meta-modelsIdentity and identifiersDirect propertiesRecognitionCapabilities and actionsHazards and failure modesStandards and interfacesContext of useSources

Bundle → Layer → Finding → Questions Filled

4 bundles · 8 layers · 8 findings · 16 questions

Understand What pixel aspect ratio is.

Concept

Concept and relations.

Concept

Concept.

  1. What is pixel aspect ratio, and how does it relate to display and storage aspect ratios? definition
  2. Which aspect ratio is meant? boundary

Standards

Standard values.

Standards

Standards.

  1. Which pixel aspect ratios do standard definition, anamorphic and digital cinema formats use? provenance
  2. Which entry fits a specific format? action
Apply Conversion and display.

Convert

Converting media.

Convert

Conversion.

  1. How can this video or image be converted or scaled correctly for square pixel display? action
  2. Which entry fits video editing? action

Diagnose

Diagnosing distortion.

Diagnose

Diagnosis.

  1. Why does this footage look stretched or squashed, and how is pixel aspect ratio metadata checked? action
  2. Which entry fits video metadata? action
History Origins.

Origins

Why non-square pixels exist.

Origins

Origins.

  1. Why did standard definition digital video use non-square pixels, and how did anamorphic widescreen arise? provenance
  2. Which entry fits video history? action

Legacy

Legacy computing.

Legacy

Legacy.

  1. How did early computer graphics modes use non-square pixels? provenance
  2. Which references are standard? provenance
Learn Teaching.

Teach

Teaching.

Teach

Teaching.

  1. How can aspect ratios be taught in media production? action
  2. Which misconceptions arise? provenance

Future

Current practice.

Future

Current.

  1. Why do modern formats use square pixels, and where do non-square pixels persist? provenance
  2. Which entry fits video formats? action

Classifiers Filled

Family
Thing Registry
Category
Cross-cutting context
Entry kind
thing
Plane
XCT
Domain
XCT.REL

What it is Filled

The ratio of the width to the height of a single pixel in a digital image or video, which is one for square pixels used in most computer graphics but differs from one in standard definition video formats, anamorphic encoding and some digital cinema and broadcast standards, so that images must be scaled correctly on display to avoid distortion; pixel aspect ratio is distinct from the display aspect ratio of the whole frame and from storage aspect ratio.

Why it exists Filled

Let an agent explain pixel aspect ratio and its relation to display and storage aspect ratios, identify the ratios used by video standards, support correct conversion and display, and support learning in video technology.

Distinguishing features Filled

  • Per-pixel ratio
  • Square versus non-square
  • Standard-specific values
  • Affects scaling

What robots and AI may and may not do Filled

Must not

  • Stretch or squash images of people in a way that distorts them.
  • Strip original metadata needed to display content correctly.
  • Alter evidential images while converting them without recording the change.

Only with a human decision

  • Converting archival or evidential footage.

May

  • Detect and correct pixel aspect ratio when converting images or video.
  • Report the pixel aspect ratio of a file from its metadata.

Moral aspects Filled

  • Distorted images can misrepresent people and events.
  • Archives depend on faithful reproduction.

Who is affected

  • People shown in images
  • Archivists and viewers

Owners Filled

Steward

Nobody: a technical property; the owner of each image answers for it.

Links to other meta-models Filled

parent

  • Q20970434 - registry parent class

related

  • width to height aspect ratio - category
  • television - video formats defining pixel ratios
  • illustration - digital images
  • software bug - distortion from mishandled ratios

What else AI and robots need to interact with it Filled

Identity and identifiers required Filled

  • Vercy registry: vr.tr.pixel-aspect-ratio
  • Wikidata: Q588886 (https://www.wikidata.org/wiki/Q588886)

Direct properties not applicable Not applicable

Not applicable

Plane XCT: no invented physical properties.

Recognition optional Filled

  • Ratio of pixel width to height
  • Square and non-square pixels
  • Display aspect ratio is the frame; storage aspect ratio is the pixel grid
  • Not physical; a ratio.

Capabilities and actions required Filled

  • explain the concept
  • identify standard ratios
  • support conversion
  • support learning

Hazards and failure modes required Filled

  • Distorted images from wrong ratio
  • Confusing pixel and display aspect ratios
  • Missing metadata

Standards and interfaces required Filled

  • Broadcast video standards
  • Digital cinema specifications
  • Video file format metadata

Context of use required Filled

  • Width to height ratio of a pixel.
  • square pixels
  • standard definition non-square pixels
  • anamorphic widescreen pixels
  • digital cinema and broadcast ratios
  • legacy computer graphics modes

Sources Filled

  1. Wikidata item Q588886: pixel aspect ratio - identity and sense of the item
  2. Wikipedia: Pixel aspect ratio - general description of the item

Open questions

  • Should anamorphic video be a separate entry?
  • How should format standards be linked?
  • How should conversion tools be linked?

Machine files

Card as JSON Specification Card backlog vercy.card/1

Provenance

thing registry research (pass 2) · unreviewed

Built from: models/things/publications/thing-q588886/spec.json