### Priors in tensor files and NNC, and scenes in MPEG-I scene description and USD

- **Tensor files as prior forms** ([prior-carriage](extensions/prior-carriage.md) §9 to §14).
  `wai.prior.safetensors` and `wai.prior.gguf` are registered prior forms: a pin's digest covers
  the whole file. Each layout is read strictly (a name twice, overlapping or uncovered bytes, a
  header past the file are each refused with a named code) and written canonically, and a reader
  refuses a file that is not canonical, so one set of tensors has one digest in each form. The
  registry lists both forms as established exact: reading hands the decoder each tensor's bytes
  as the file holds them.
- **The integer-quantised profile `wai-int/1`** (§10): every tensor a signed integer the kernel
  reads as it is, every scale itself an integer tensor, nothing floating point, so loading does no
  rounding. Two bindings map native integer artifacts to named tensors and back, byte for byte:
  `wsr1/1` (the `WSR1` prior of exact-upscale) and `whm1/1` (the `WHM1` model of
  integer-payloads). The two trained `WSR1` priors of the exact-upscale corpus, carried in each
  form, load to the same native bytes and give the same upscaled pictures.
- **NNC read and written** (§12 and Appendix A): the subset of ISO/IEC 15938-17 an open
  implementation of its 2024 edition reads — the start, model parameter set and topology units,
  and data units of integer tensors under the standard's context-adaptive arithmetic coding or
  of raw 32-bit floats. Quantised payloads, dependent quantisation, block scans and the other unit
  types are refused with `nnc_not_read`, naming what was met; the standard's own clauses were not
  read. Measured against that implementation (§12.4): its decoder reads our files to the same
  integers, its encoder writes byte-identical data units, and our reader reads its bitstreams.
- **Scene carriage** ([scene-carriage](extensions/scene-carriage.md)): a world, an audio scene,
  a world's assets and timed media items written as an ISO/IEC 23090-14 glTF document
  (`MPEG_media`, `MPEG_buffer_circular`, `MPEG_accessor_timed`, `MPEG_audio_spatial`,
  `MPEG_texture_video`) and as a USD layer of the USD Core Specification v1.0.1 (prims,
  translate operations, time samples, asset references by `urn:wai:asset:`), each carrying the
  WAI bytes exactly. Reading a document WAI wrote gives the same bytes, and is refused unless
  writing them again gives the document; a document WAI did not write becomes new WAI bytes
  under stated rules, refused where a rotation, an inexact position, a time between samples, a
  gain in decibels or media that names no WAI object would not carry. Meshes travel by content
  hash, as a world names its assets.
- **Reference implementation and corpora.** `wai-rs` features `prior_wire` and `scene_map`;
  corpora [`live-conformance/prior-forms/`](live-conformance/prior-forms/) and
  [`live-conformance/scene/`](live-conformance/scene/), with negative controls for every code,
  and their independent verifiers `prior_forms_verify.py` and `scene_verify.py`.

