# RFC 9559: Matroska Media Container Format Specification

- id: src_01M569CRYYGFTE1G7VS17C9Z5J
- type: source · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=metadata_checked, execution=not_run, review=unreviewed
- categories: T10 · tags: level:established, matroska, mkv, container, ietf, webm, foundational
- updated: 2026-10-18T01:18:06.802Z
- url: https://veyrul.com/sources/src_01M569CRYYGFTE1G7VS17C9Z5J

Source: https://www.rfc-editor.org/rfc/rfc9559.html

```json
{
  "archived": null,
  "checked_at": "2026-10-17T00:00:00.000Z",
  "parent_url": null,
  "usefulness": "IETF Standards Track specification of the Matroska container (EBML-based; seeking, chapters, tags, attachments, multiple audio/video/subtitle tracks). Foundation for MKV and WebM.",
  "source_type": "documentation",
  "availability": "available",
  "dependencies": [],
  "source_owner": "IETF CELLAR WG",
  "next_check_at": "2026-10-24T00:00:00.000Z",
  "successor_url": null,
  "hardware_notes": null,
  "known_limitations": [],
  "upstream_updated_at": null
}
```

Evidence claims:
- [sourced_fact] RFC 9559, October 2024, Internet Standards Track; authors Lhomme, Bunkus, Rice; defines the Matroska container structure and updates RFC 8794 to allow EBML Element ID 0x80; a container spec, not a codec. · source: https://www.rfc-editor.org/rfc/rfc9559.html
- [upstream_claim] Matroska.org describes Matroska as an extensible, open source, open standard multimedia container used for .mkv/.mka/.mks/.mk3d and the basis of .webm. · source: https://www.matroska.org/index.html
- [upstream_claim] Research review verdict at export: reviewed (as of 2026-10-17). Recorded by the research pipeline, not a hub review outcome; evidence.review stays unreviewed until an independent reviewer records one.

Rights:
- documentation: license=unknown hosting=unknown redistribution=unknown modification=unknown training=unknown · IETF Trust legal provisions for RFCs not read here; unchecked. · evidence: https://www.rfc-editor.org/rfc/rfc9559.html

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