# pack-conformance/loudness — integer loudness and the loudness statement

The corpus of [`extensions/packaging.md`](../../extensions/packaging.md) §12, in one file,
`vectors.json`.

**Provenance.** Generated here by `wai_loudness_vectors gen` (`wai-rs`, feature `loudness`):
programmes given as formulas of integers (one period of a 1 kHz tone at 48 kHz, `sine_1k`, which
the text and the generator state; a linear congruential generator's noise; silence), their
measurements, and statements signed with an Ed25519 key on a fixed 32-byte seed; no recording
and no input from outside this repository.

- `programmes` (§12.2, §12.3) are each a `rate`, a number of `channels` and `segments`, each of
  `frames` sample frames with a source a channel: `zero`; `tone`, `sine_1k[k mod 48] × num / den`,
  floored, for the segment's frame `k`; `noise`, from `x` = `seed`, each sample
  `x ← (x × 1 103 515 245 + 12 345) mod 2^31` then `⌊x / 2^8⌋ mod (2·amp + 1) − amp`; `spike`, the
  same noise with frame `at` at 32 767. `outcome` is the measurement: `frames`, `blocks`,
  `gated`, `integrated_milli`, `peak`, `peak_milli`.
- `logarithms` (§12.3) are pairs of an integer and its *L*, both in decimal, the integer from 1
  to 2^128 − 1.
- `statements` (§12.5, §12.6) are each a `statement`'s text, the `receipt_hash` a verifier
  expects (or `null`) and the programme it holds as its `source` (or `null`); `outcome` is
  `verified`, with the component, loudness, gain and `limited`, or `refuse` and the reason.

Everything is synthetic: the key attests nothing. The generator holds each programme to the
loudness BS.1770's calibration or the programme's construction declares, and each statement's
outcome is the one it was written to have.

`wai_loudness_vectors verify` and `tests/loudness.rs` check that the file regenerates byte for
byte and that `wai-rs` reaches every stated outcome. `../loudness_verify.py` is the second
implementation, written from the extension's text, which also mutates copies of the corpus and
drops each of its own checks in turn and requires each to be caught.