open-standards/wai/glossary/SCHEMA.md

WAI codec glossary — schema

Canonical, machine-readable catalog of media codecs surveyed for WAI capability registration. Lives in codecs.json alongside this schema.

The glossary is reference material — it is not the registry of WAI capabilities (that lives in ../SPEC.md §5). Listing a codec here means it exists and is documented; listing a codec in the spec means a conforming sink MAY or MUST implement it.

Provenance

Originally extracted from the inline JavaScript array in wai-info-page/wai-glossary.html (the user's purpose-built reference page) into typed form, then ported to JSON for language-neutral consumption.

Mirrored as a typed Astro module at wai-transaction-science-web/src/data/codecs.ts — the site renders the JSON statically at build time so search and filters work without JavaScript.

Top-level shape

{
  "schema":  "https://github.com/Transaction-Science/open-standards/blob/main/wai/glossary/SCHEMA.md",
  "entries": [ Codec, ... ]
}

Codec entry

{
  name:     string;     // canonical short name, e.g. "AV1", "HEVC", "JPEG-XL"
  year:     number;     // year of first published spec or first release
  org:      string;     // standards body, vendor, or research group that owns lineage
  modality: "image" | "video" | "audio" | "speech";
  era:      "classical" | "neural";
  status:   "success" | "niche" | "superseded" | "failed" | "academic" | "emerging";
  lineage:  "industry" | "standards" | "academic" | "opensource";
  desc:     string;     // 1–3 sentence factual summary — what it is, who made it,
                        // its design choice, its current footprint. Self-referential
                        // only (no "better than X", no competitor framing).
}

Field values

• status is descriptive, not normative:
  • success — the codec carries non-trivial production traffic today.
  • niche — alive in specific contexts (icons, pipelines, debug tools, particular hardware).
  • superseded — readable everywhere, written nowhere modern.
  • failed — shipped, did not achieve adoption.
  • academic — published only in research; no production deployment.
  • emerging — recent enough that adoption trajectory is undetermined.
• lineage captures origin culture (affects how the codec evolves):
  • industry — vendor-driven (a company shipping a product).
  • standards — formal body (ISO, ITU-T, IETF, IEEE, SMPTE).
  • academic — research lab.
  • opensource — community-led from inception.
• era marks the discontinuity: classical = handcrafted DCT/wavelet/predictive, neural = end-to-end learned bitstream.

Contributing

Two operations:

1. Add a codec — append a new entry to entries[]. Keep entries roughly chronological within their modality block.
2. Correct a description — edit desc. Aim for factual density over flair: spec year, the spec body that owns it, the architectural choice that defines it, its current deployment footprint. No comparisons; no opinions about quality unless backed by a citation in the description.

A patch that touches only codecs.json requires no test run. A patch that adds a new field or status enum value should:

1. Update SCHEMA.md first (define the field).
2. Update the typed module at wai-transaction-science-web/src/data/codecs.ts and the glossary page that consumes it (wai-transaction-science-web/src/pages/glossary.astro).

Relationship to the WAI spec

A codec listed here becomes a WAI capability (e.g., wai.image.jxl) only when the spec registers it in SPEC.md §5. Registration carries normative requirements: a canonical reference library, a payload format declaration, and conformance via bit-exact decode-equivalence. The glossary documents the full landscape; the spec selects from it.