{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "One 78rpm disc, and the highest frequency it still carries above its own noise",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "identifier",
    "edge_hz",
    "asymptote_db",
    "sample_rate_hz"
  ],
  "properties": {
    "identifier": {
      "type": "string",
      "description": "Internet Archive item identifier. One side of one disc.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "year": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Item date as the archive records it. See the README: two sides of one disc disagree 1.8 per cent of the time.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "edge_hz": {
      "type": [
        "number",
        "null"
      ],
      "description": "The edge: highest frequency in 200 Hz to 12 kHz whose loud-frame excess over quiet-frame level clears the disc's own asymptote by 6 dB. Null means nothing anywhere in the band cleared it.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "asymptote_db": {
      "type": [
        "number",
        "null"
      ],
      "description": "The disc's own floor: median loud-over-quiet excess across 13 to 17 kHz.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "noise_6k10k_db": {
      "type": [
        "number",
        "null"
      ],
      "description": "Mean quiet-frame level over 6 to 10 kHz, in dB, on the transfer's own scale.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "prog_6k10k_db": {
      "type": [
        "number",
        "null"
      ],
      "description": "Mean loud-frame level over the same band.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "seconds": {
      "type": [
        "number",
        "null"
      ],
      "description": "Duration of the transfer measured.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "frames": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Number of 8192-sample analysis frames at 4096 hop.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "sample_rate_hz": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Sample rate the measurement was made at. The statistic is rate dependent; see the README.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "measured_sha256": {
      "type": [
        "string",
        "null"
      ],
      "description": "sha256 of the exact bytes measured. The audio is not kept and not redistributed, so this is how you confirm you hold what we held.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "measured_bytes": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Length of those bytes.",
      "x-origin": "built",
      "x-source": "src:aw-edge-measurement"
    },
    "condition": {
      "type": [
        "string",
        "null"
      ],
      "description": "The archive's condition grading for the physical disc. A curator's judgement, not a measurement.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "diameter_in": {
      "type": [
        "integer",
        "null"
      ],
      "description": "Disc diameter in inches, 10 or 12.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "country": {
      "type": [
        "string",
        "null"
      ],
      "description": "The archive's coverage field.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "genre": {
      "type": [
        "string",
        "null"
      ],
      "description": "The archive's free-text genre, lowercased and with \"fox trot\" folded to \"foxtrot\".",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "publisher": {
      "type": [
        "string",
        "null"
      ],
      "description": "Label as the archive records it.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "playback_turnover_hz": {
      "type": [
        "number",
        "null"
      ],
      "description": "Playback equalisation turnover stated in the item description, if stated.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    },
    "playback_rolloff_db": {
      "type": [
        "number",
        "null"
      ],
      "description": "Playback equalisation rolloff stated in the item description, if stated. Null does not mean flat.",
      "x-origin": "redistributed",
      "x-source": "src:internet-archive-great78"
    }
  }
}