{
  "title": "Inside a Virtual Acoustic Object — Virtual Acoustic Objects",
  "text": "MODAVIS (2026). Inside a Virtual Acoustic Object — Virtual Acoustic Objects. Research notebooks, September 2026 · expanded edition. https://modavis.org/editions/2026-09-r3/vao/structure/",
  "bibtex": "@misc{modavis_vao_structure_2026_09_r3,\n  author = {{MODAVIS}},\n  title = {Inside a Virtual Acoustic Object — Virtual Acoustic Objects},\n  year = {2026},\n  month = {09},\n  version = {2026-09-r3},\n  url = {https://modavis.org/editions/2026-09-r3/vao/structure/},\n  note = {Content SHA-256: 20b5352588a74bf064acbe58b0aad666b62d27cce47dcc0adabe53ba2a4a7d17}\n}",
  "url": "https://modavis.org/editions/2026-09-r3/vao/structure/",
  "sha256": "20b5352588a74bf064acbe58b0aad666b62d27cce47dcc0adabe53ba2a4a7d17",
  "edition": "2026-09-r3",
  "date": "2026-09-26",
  "canonicalPayload": "{\"book\":{\"number\":\"01\",\"slug\":\"vao\",\"title\":\"Virtual Acoustic Objects\"},\"chapter\":{\"blocks\":[{\"text\":\"VAO 0.5.0 separates the semantic release from its physical carriers. The manifest describes resources and their relationships. A carrier packages exact realizations of those resources for transport. Changing the delivery arrangement does not, by itself, create a different semantic release.\",\"type\":\"p\"},{\"id\":\"carrier-roles\",\"text\":\"Three carrier roles\",\"type\":\"heading\"},{\"headers\":[\"Carrier\",\"Purpose\"],\"rows\":[[\"Bootstrap\",\"A small entry point for discovery and evidence, with references to further resources.\"],[\"Preservation closure\",\"Contains every realization required by the complete release.\"],[\"Custom\",\"A locally materialized selection for a particular task or byte budget.\"]],\"type\":\"table\"},{\"id\":\"container\",\"text\":\"A small, explicit container\",\"type\":\"heading\"},{\"label\":\"VAO 0.5.0 · root structure\",\"text\":\"instrument.vao\\n├── mimetype\\n├── vao-manifest.json\\n├── META-INF/\\n│   └── vao-carrier.json\\n└── payload/\\n    └── …\",\"type\":\"code\"},{\"text\":\"The manifest fixes semantic identity. The carrier descriptor maps embedded payload members to that manifest. Byte sizes and SHA-256 digests let a client check whether a retrieved realization is the one the release actually identifies.\",\"type\":\"p\"},{\"text\":\"Where the repository supports byte ranges, a client can retrieve an exact stored ZIP member without first downloading the complete preservation carrier. This depends on the delivery service as well as the package.\",\"title\":\"Selective access\",\"type\":\"note\"},{\"id\":\"resource-identity\",\"text\":\"From a resource to its exact bytes\",\"type\":\"heading\"},{\"headers\":[\"Concept\",\"Illustrative example\"],\"rows\":[[\"Logical asset\",\"A recording of one documented take.\"],[\"Realization\",\"One particular encoding of that recording, identified by byte size and SHA-256.\"],[\"Distribution\",\"A location from which those exact bytes can be acquired.\"],[\"Asset group\",\"A declared set of resources and dependencies needed for a particular capability.\"]],\"type\":\"table\"},{\"text\":\"A filename is a convenient label, not an identity guarantee. Re-encoding audio, editing a mesh or replacing an image changes the exact realization. Even when two files serve the same intellectual role, a client must not substitute one for the other without an explicit release description. A changed URL can still deliver the same realization; an unchanged URL can deliver different bytes.\",\"type\":\"p\"},{\"id\":\"delivery-sequence\",\"text\":\"What happens during selective delivery\",\"type\":\"heading\"},{\"items\":[\"Read the bootstrap manifest and establish the fixed semantic release being requested.\",\"Choose a declared group, including its dependencies, that supports the intended use.\",\"Resolve the pinned preservation carrier and exact member mapping.\",\"Retrieve the member, then check its decoded byte length and SHA-256 against the manifest.\",\"Record the selection and materialized carrier so that a later user can understand what was acquired.\"],\"type\":\"list\"},{\"text\":\"A small carrier is not automatically a complete preservation copy. Group completeness is a statement about included realizations and their recursively required groups. A browser preview might be sufficient for inspecting an image, while a later acoustic analysis needs another group. The release contract makes that difference explicit instead of letting a partial download masquerade as the whole object.\",\"type\":\"p\"},{\"text\":\"VAO 0.5.0 names the exchange contract. A reference instrument’s 0.5.0-rc.2 package label names that publisher’s object release. Similar-looking version strings do not establish an equivalence between the two.\",\"title\":\"Release version and format version\",\"type\":\"note\"}],\"intro\":\"One semantic release. Multiple ways to carry and access its resources.\",\"slug\":\"structure\",\"sources\":[{\"detail\":\"The versioned specification and reference tools.\",\"href\":\"https://doi.org/10.5281/zenodo.22214248\",\"label\":\"VAO Standard 0.5.0\"}],\"title\":\"Inside a Virtual Acoustic Object\"},\"date\":\"2026-09-26\",\"edition\":\"2026-09-r3\",\"figures\":{}}",
  "payload": {
    "edition": "2026-09-r3",
    "date": "2026-09-26",
    "book": {
      "slug": "vao",
      "title": "Virtual Acoustic Objects",
      "number": "01"
    },
    "chapter": {
      "slug": "structure",
      "title": "Inside a Virtual Acoustic Object",
      "intro": "One semantic release. Multiple ways to carry and access its resources.",
      "blocks": [
        {
          "type": "p",
          "text": "VAO 0.5.0 separates the semantic release from its physical carriers. The manifest describes resources and their relationships. A carrier packages exact realizations of those resources for transport. Changing the delivery arrangement does not, by itself, create a different semantic release."
        },
        {
          "type": "heading",
          "text": "Three carrier roles",
          "id": "carrier-roles"
        },
        {
          "type": "table",
          "headers": [
            "Carrier",
            "Purpose"
          ],
          "rows": [
            [
              "Bootstrap",
              "A small entry point for discovery and evidence, with references to further resources."
            ],
            [
              "Preservation closure",
              "Contains every realization required by the complete release."
            ],
            [
              "Custom",
              "A locally materialized selection for a particular task or byte budget."
            ]
          ]
        },
        {
          "type": "heading",
          "text": "A small, explicit container",
          "id": "container"
        },
        {
          "type": "code",
          "label": "VAO 0.5.0 · root structure",
          "text": "instrument.vao\n├── mimetype\n├── vao-manifest.json\n├── META-INF/\n│   └── vao-carrier.json\n└── payload/\n    └── …"
        },
        {
          "type": "p",
          "text": "The manifest fixes semantic identity. The carrier descriptor maps embedded payload members to that manifest. Byte sizes and SHA-256 digests let a client check whether a retrieved realization is the one the release actually identifies."
        },
        {
          "type": "note",
          "title": "Selective access",
          "text": "Where the repository supports byte ranges, a client can retrieve an exact stored ZIP member without first downloading the complete preservation carrier. This depends on the delivery service as well as the package."
        },
        {
          "type": "heading",
          "text": "From a resource to its exact bytes",
          "id": "resource-identity"
        },
        {
          "type": "table",
          "headers": [
            "Concept",
            "Illustrative example"
          ],
          "rows": [
            [
              "Logical asset",
              "A recording of one documented take."
            ],
            [
              "Realization",
              "One particular encoding of that recording, identified by byte size and SHA-256."
            ],
            [
              "Distribution",
              "A location from which those exact bytes can be acquired."
            ],
            [
              "Asset group",
              "A declared set of resources and dependencies needed for a particular capability."
            ]
          ]
        },
        {
          "type": "p",
          "text": "A filename is a convenient label, not an identity guarantee. Re-encoding audio, editing a mesh or replacing an image changes the exact realization. Even when two files serve the same intellectual role, a client must not substitute one for the other without an explicit release description. A changed URL can still deliver the same realization; an unchanged URL can deliver different bytes."
        },
        {
          "type": "heading",
          "text": "What happens during selective delivery",
          "id": "delivery-sequence"
        },
        {
          "type": "list",
          "items": [
            "Read the bootstrap manifest and establish the fixed semantic release being requested.",
            "Choose a declared group, including its dependencies, that supports the intended use.",
            "Resolve the pinned preservation carrier and exact member mapping.",
            "Retrieve the member, then check its decoded byte length and SHA-256 against the manifest.",
            "Record the selection and materialized carrier so that a later user can understand what was acquired."
          ]
        },
        {
          "type": "p",
          "text": "A small carrier is not automatically a complete preservation copy. Group completeness is a statement about included realizations and their recursively required groups. A browser preview might be sufficient for inspecting an image, while a later acoustic analysis needs another group. The release contract makes that difference explicit instead of letting a partial download masquerade as the whole object."
        },
        {
          "type": "note",
          "title": "Release version and format version",
          "text": "VAO 0.5.0 names the exchange contract. A reference instrument’s 0.5.0-rc.2 package label names that publisher’s object release. Similar-looking version strings do not establish an equivalence between the two."
        }
      ],
      "sources": [
        {
          "label": "VAO Standard 0.5.0",
          "href": "https://doi.org/10.5281/zenodo.22214248",
          "detail": "The versioned specification and reference tools."
        }
      ]
    },
    "figures": {}
  }
}