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Appendices

Appendices contain normative and informative reference material essential for correct and interoperable use of the MIND Standard. Some appendices are fully normative (e.g., coordinate conventions), and others are informative guidance.

Glossary (Normative)​

This glossary defines required terminology used across the specification.

Sample — a single timestamped instance of a modality.
Stream — ordered sequence of samples of one modality.
Modality — a typed data structure representing a data domain.
Metadata Profile — structured description of bodies, sensors, robots, objects, or calibration.
Environment Node — spatial node (Frame, Object, Region, Anchor).
EventPoint — an instantaneous temporal occurrence.
IntervalEvent — event with start and end.
Container — top-level MIND data structure.
World Root — required environment root coordinate frame.

(The full glossary would continue in real spec.)

Canonical Coordinate Conventions (Normative)​

MIND mandates a single, unified coordinate convention:

  • Right-handed
  • Y-up
  • Z-forward
  • Units: meters
  • Rotations: quaternions in [x,y,z,w] order
  • Camera intrinsics follow OpenCV conventions

All data MUST respect these conventions unless a metadata profile explicitly documents an override.

Reference Pipelines (Informative)​

ASCII overview:

Capture → Sync → Align → Container Build → Train/Infer → Playback/Sim

Real-time XR / robotics pipelines MUST follow Section 8 serialization rules.

Canonical JSON Examples (Normative)​

Included separately as examples.

Schema Reference Table (Normative)​

Each modality, metadata profile, and event type MUST map to a schema entry.

Validation Rule Index (Normative)​

Examples:

  • VR-001: Stream timestamps MUST be non-decreasing.
  • VR-014: Every modality stream MUST reference required metadata.
  • VR-023: Environment graph MUST contain world_root.

Error Class Reference (Normative)​

Canonical error classes:

  • INVALID_CONTAINER
  • SCHEMA_MISMATCH
  • UNRESOLVED_REFERENCE
  • TIMESTAMP_VIOLATION
  • METADATA_INVALID
  • EXTENSION_REQUIRED_UNSUPPORTED
  • INDEX_INVALID

Deprecated & Reserved (Normative)​

  • Reserved identifiers: world_root, container_version.
  • Deprecated fields MUST remain valid for one major version.

Design Rationale (Informative)​

Explains reasoning behind:

  • dual timestamps
  • namespaced modalities
  • extended event hierarchy
  • dynamic environment nodes
  • metadata inheritance

Summary​

Appendices provide essential reference material and MUST be considered part of the MIND standard.