{ "title": "Inside a Virtual Acoustic Object — Virtual Acoustic Objects", "text": "MODAVIS (2026). Inside a Virtual Acoustic Object — Virtual Acoustic Objects. Research notebooks, September 2026 · Connected evidence edition. https://modavis.org/editions/2026-09-r6/vao/structure/", "bibtex": "@misc{modavis_vao_structure_2026_09_r6,\n author = {{MODAVIS}},\n title = {Inside a Virtual Acoustic Object — Virtual Acoustic Objects},\n year = {2026},\n month = {09},\n version = {2026-09-r6},\n url = {https://modavis.org/editions/2026-09-r6/vao/structure/},\n note = {Content SHA-256: 30a1a4d60047302776af8a6234a7687f9a238e82666dd11688bf31d67e9cafad}\n}", "url": "https://modavis.org/editions/2026-09-r6/vao/structure/", "sha256": "30a1a4d60047302776af8a6234a7687f9a238e82666dd11688bf31d67e9cafad", "edition": "2026-09-r6", "date": "2026-09-26", "canonicalPayload": "{\"book\":{\"number\":\"01\",\"slug\":\"vao\",\"title\":\"Virtual Acoustic Objects\"},\"chapter\":{\"blocks\":[{\"items\":[{\"detail\":\"A continuous worked example: readable explanations, exact records and the limits of each claim.\",\"href\":\"/notebooks/standards/cuntz/\",\"label\":\"Learn this through the Cuntz organ\"}],\"type\":\"links\"},{\"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\"},{\"boundary\":\"A downloaded bootstrap does not prove that every external resource has been fetched or verified.\",\"caseLabel\":\"Cuntz\",\"concept\":\"A manifest describes the research object and its resource relationships. A carrier is a package that delivers some or all of those exact resources.\",\"evidence\":\"Released record\",\"expanded\":false,\"id\":\"cuntz-carriers\",\"scenario\":\"The published Cuntz record offers a bootstrap carrier and a preservation carrier. The release states that both carry the same manifest; the preservation carrier includes every declared realization.\",\"sources\":[{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},{\"detail\":\"The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2.\",\"href\":\"https://doi.org/10.5281/zenodo.22214248\",\"label\":\"VAO Standard 0.5.0\"}],\"steps\":[{\"text\":\"The bootstrap supplies the semantic inventory and core evidence. It lets a reader discover what exists without first downloading all the media.\",\"title\":\"Begin with the inventory\"},{\"text\":\"A geometry inspection needs the selected model and its dependencies. A playable experience may need audio, control mappings and other groups. Reading metadata does not make those resources locally available.\",\"title\":\"Request the required material\"},{\"text\":\"The complete preservation carrier supports the full declared realization inventory. Cite the exact release and record which carrier or selected closure you actually acquired.\",\"title\":\"Choose preservation deliberately\"}],\"takeaway\":\"One research release can have several delivery packages without becoming several historical interpretations.\",\"title\":\"Why does the Cuntz release offer two VAO downloads?\",\"type\":\"example\"},{\"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\"},{\"boundary\":\"The smaller web derivative has not been retroactively inserted into the published VAO manifest.\",\"caseLabel\":\"Cuntz\",\"concept\":\"A logical asset names a role in the research object. A realization identifies one exact encoding of that asset. A distribution says where a realization can be obtained.\",\"evidence\":\"Released record\",\"expanded\":false,\"id\":\"cuntz-asset\",\"scenario\":\"The Cuntz manifest groups the 4010243_segmented_03b2 FBX source and GLB runtime model under one logical model asset. Their byte sizes, formats and digests differ.\",\"sources\":[{\"detail\":\"Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release.\",\"href\":\"https://doi.org/10.5281/zenodo.22151203\",\"label\":\"Cuntz Positiv · VAO 0.5.0-rc.2\"},{\"detail\":\"The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2.\",\"href\":\"https://doi.org/10.5281/zenodo.22214248\",\"label\":\"VAO Standard 0.5.0\"}],\"steps\":[{\"text\":\"The asset groups representations serving the named model role. It supplies the connection that a filename alone cannot guarantee.\",\"title\":\"Identify the shared asset\"},{\"text\":\"The FBX source is 61,745,100 bytes; the released GLB is 115,416,448 bytes. The GLB is marked derived, with a model-conversion activity. Each has an independent SHA-256.\",\"title\":\"Inspect each realization\"},{\"text\":\"The smaller model served by this notebook is another derived file. Its caption and file identity distinguish it from both published realizations, and its provenance leads back to the released GLB.\",\"title\":\"Identify the notebook derivative separately\"}],\"takeaway\":\"“Same asset” expresses a relationship; “same bytes” is a separate, testable claim.\",\"title\":\"How can two model files represent one asset?\",\"type\":\"example\"},{\"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\"},{\"id\":\"realization-status\",\"text\":\"Say how each representation came into being\",\"type\":\"heading\"},{\"text\":\"VAO 0.5.0 distinguishes statuses including captured, authored, converted, derived, simulated, inferred, reconstructed, redacted, hybrid and undetermined. These labels locate a representation within its history. A captured signal and a simulated signal may both be playable, but their scientific roles differ. A converted encoding preserves a relationship to an input; a reconstructed surface embodies additional assumptions. Retain the derivation evidence needed to interpret the chosen status.\",\"type\":\"p\"},{\"text\":\"Use exact realization identity when citing or comparing output. “The organ model” is too broad if a release contains a measured point cloud, a reconstructed mesh and a reduced mobile geometry. Name the relevant realization and retain its byte identity, then explain the relation it has to the other forms of the asset.\",\"type\":\"p\"},{\"items\":[{\"detail\":\"A worked guide to release, realization and distribution identity.\",\"href\":\"/notebooks/vao/delivery/\",\"label\":\"Follow an asset across carriers\"},{\"detail\":\"The relationships that make media interpretable.\",\"href\":\"/notebooks/vao/acoustics/\",\"label\":\"Time, space and acoustic response\"}],\"type\":\"links\"}],\"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\"},{\"detail\":\"Normative standard, profile index, Dynamic Delivery Profile and conformance specification in the versioned release.\",\"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-r6\",\"figures\":{}}", "payload": { "edition": "2026-09-r6", "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": "links", "items": [ { "label": "Learn this through the Cuntz organ", "href": "/notebooks/standards/cuntz/", "detail": "A continuous worked example: readable explanations, exact records and the limits of each claim." } ] }, { "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": "example", "id": "cuntz-carriers", "title": "Why does the Cuntz release offer two VAO downloads?", "concept": "A manifest describes the research object and its resource relationships. A carrier is a package that delivers some or all of those exact resources.", "scenario": "The published Cuntz record offers a bootstrap carrier and a preservation carrier. The release states that both carry the same manifest; the preservation carrier includes every declared realization.", "steps": [ { "title": "Begin with the inventory", "text": "The bootstrap supplies the semantic inventory and core evidence. It lets a reader discover what exists without first downloading all the media." }, { "title": "Request the required material", "text": "A geometry inspection needs the selected model and its dependencies. A playable experience may need audio, control mappings and other groups. Reading metadata does not make those resources locally available." }, { "title": "Choose preservation deliberately", "text": "The complete preservation carrier supports the full declared realization inventory. Cite the exact release and record which carrier or selected closure you actually acquired." } ], "takeaway": "One research release can have several delivery packages without becoming several historical interpretations.", "boundary": "A downloaded bootstrap does not prove that every external resource has been fetched or verified.", "sources": [ { "label": "Cuntz Positiv · VAO 0.5.0-rc.2", "href": "https://doi.org/10.5281/zenodo.22151203", "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release." }, { "label": "VAO Standard 0.5.0", "href": "https://doi.org/10.5281/zenodo.22214248", "detail": "The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2." } ], "expanded": false, "caseLabel": "Cuntz", "evidence": "Released record" }, { "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": "example", "id": "cuntz-asset", "title": "How can two model files represent one asset?", "concept": "A logical asset names a role in the research object. A realization identifies one exact encoding of that asset. A distribution says where a realization can be obtained.", "scenario": "The Cuntz manifest groups the 4010243_segmented_03b2 FBX source and GLB runtime model under one logical model asset. Their byte sizes, formats and digests differ.", "steps": [ { "title": "Identify the shared asset", "text": "The asset groups representations serving the named model role. It supplies the connection that a filename alone cannot guarantee." }, { "title": "Inspect each realization", "text": "The FBX source is 61,745,100 bytes; the released GLB is 115,416,448 bytes. The GLB is marked derived, with a model-conversion activity. Each has an independent SHA-256." }, { "title": "Identify the notebook derivative separately", "text": "The smaller model served by this notebook is another derived file. Its caption and file identity distinguish it from both published realizations, and its provenance leads back to the released GLB." } ], "takeaway": "“Same asset” expresses a relationship; “same bytes” is a separate, testable claim.", "boundary": "The smaller web derivative has not been retroactively inserted into the published VAO manifest.", "sources": [ { "label": "Cuntz Positiv · VAO 0.5.0-rc.2", "href": "https://doi.org/10.5281/zenodo.22151203", "detail": "Published manifest: identities, measurement observations, realization digests, profiles and rights. Exact examples checked against this release." }, { "label": "VAO Standard 0.5.0", "href": "https://doi.org/10.5281/zenodo.22214248", "detail": "The standard contract is separate from the Cuntz dataset content version 0.5.0-rc.2." } ], "expanded": false, "caseLabel": "Cuntz", "evidence": "Released record" }, { "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." }, { "type": "heading", "id": "realization-status", "text": "Say how each representation came into being" }, { "type": "p", "text": "VAO 0.5.0 distinguishes statuses including captured, authored, converted, derived, simulated, inferred, reconstructed, redacted, hybrid and undetermined. These labels locate a representation within its history. A captured signal and a simulated signal may both be playable, but their scientific roles differ. A converted encoding preserves a relationship to an input; a reconstructed surface embodies additional assumptions. Retain the derivation evidence needed to interpret the chosen status." }, { "type": "p", "text": "Use exact realization identity when citing or comparing output. “The organ model” is too broad if a release contains a measured point cloud, a reconstructed mesh and a reduced mobile geometry. Name the relevant realization and retain its byte identity, then explain the relation it has to the other forms of the asset." }, { "type": "links", "items": [ { "label": "Follow an asset across carriers", "href": "/notebooks/vao/delivery/", "detail": "A worked guide to release, realization and distribution identity." }, { "label": "Time, space and acoustic response", "href": "/notebooks/vao/acoustics/", "detail": "The relationships that make media interpretable." } ] } ], "sources": [ { "label": "VAO Standard 0.5.0", "href": "https://doi.org/10.5281/zenodo.22214248", "detail": "The versioned specification and reference tools." }, { "label": "VAO Standard 0.5.0", "href": "https://doi.org/10.5281/zenodo.22214248", "detail": "Normative standard, profile index, Dynamic Delivery Profile and conformance specification in the versioned release." } ] }, "figures": {} } }