appears_in: []
depends_on: []
deprecated: false
description: "The Audio Commons Ontology has been created in the context of the European\
  \ project [Audio Commons](https://www.audiocommons.org/), which were aimed at favouring\
  \ sharing and reuse of audio content (both of musical and non-musical nature), specially\
  \ using [Creative Commons](https://creativecommons.org/) licenses.\n\nIt is designed\
  \ specifically to integrate access to multiple heterogeneously structured audio\
  \ content providers. In particular the following ones have been considered in the\
  \ project:\n- [Freesound](https://freesound.org/), a collaborative database of Creative\
  \ Commons Licensed sounds;\n- [Jamendo](https://www.jamendo.com/), a music website\
  \ for independent artists;\n- [Europeana Sounds](https://www.eusounds.eu/), a European\
  \ project collecting and sharing data from several archives of sounds and sound-related\
  \ media;\n- [Internet Archive](https://archive.org/), a non-profit library of millions\
  \ of freely accessible media contents.\n\n### The base model\n<center> ![A diagram\
  \ showing the entities Work, Expression, Manifestation, Item](./img/FRBR-Group-1-entities-and-basic-relations.svg.png)\
  \ </center>\nThe Audio Commons ontology is based on [Functional Requirements for\
  \ Bibliographic Records (FRBR)](https://en.wikipedia.org/wiki/Functional_Requirements_for_Bibliographic_Records),\
  \ a bibliographic model designed for user tasks of retrieval and access in online\
  \ library catalogues and bibliographic databases. FRBR distinguish the products\
  \ of intellectual or artistic endeavor in four main classes: work, expression, manifestation,\
  \ item. It is available as RDF vocabulary at https://vocab.org/frbr/core. For further\
  \ information on FRBR, check the [standard](https://repository.ifla.org/handle/123456789/811).\n\
  \nAnother important model related to audio is the [Music Ontology](http://musicontology.com/),\
  \ which is also based on the FRBR model. Our ontology is more generic than the Music\
  \ Ontology but is interoperable with it to support the specificities of music-related\
  \ audio content.\n\nThe Audio Commons ontology works also in conjunction with\n\
  - [Dublin Core](https://www.dublincore.org/specifications/dublin-core/dcmi-terms/)\
  \ for basic metadata,\n- [EBU Core](https://www.ebu.ch/metadata/ontologies/ebucore/)\
  \ for technical properties of audio files,\n- [SKOS](https://www.w3.org/TR/skos-primer/)\
  \ to support taxonomic classifications,\n- [Creative Commons Licensing schema](https://creativecommons.org/ns)\
  \ to represent media licensing,\n- [Event ontology](http://motools.sf.net/event/event.html)\
  \ for the formalisation of events,\n- [Audio Features Ontology](https://w3id.org/afo/onto/)\
  \ for the characterisation of audio features.\n\n### Ontology overview\n\n![A diagram\
  \ showing the main classes of the Audio Commons ontology](./img/AC-Ontology-Skeleton.png)\n\
  \nThe figure above shows the most general classes and properties of the Audio Commons\
  \ ontology and their relationship with classes of the FRBR and the Music Ontology:\n\
  - **`ac:AudioExpression`**, the specific intellectual or artistic form that a work\
  \ takes each time it is _realised_, in the audio domain, e.g., the recording or\
  \ synthesis of music or sounds;\n- **`ac:AudioManifestation`**, the physical embodiment\
  \ of an audio expression, e.g., a musical track, a sound, an album; \n- **`ac:AudioItem`**,\
  \ a single exemplar of an audio manifestation, e.g., a copy of a CD or a specific\
  \ media file.\n\nThe FRBR class Work, representing a distinct intellectual or artistic\
  \ creation on a more conceptual level, has not been specialised in Audio Commons.\n\
  \nThe Audio Commons ontology provides a generic schema for audio classification\
  \ through the property **`ac:audioCategory`** that associates any audio expression,\
  \ manifestation, or item to some generic **`ac:AudioCategory`**. These two terms\
  \ can be specialised to provide spefic categorisations.\n\n### Manifestations: audio\
  \ clips and collections\n\n![A diagram showing the main classes of the Audio Commons\
  \ ontology](./img/AC-Ontology-Manifestation.png)\n\nThe figure above shows classes\
  \ and properties related to audio manifestations. An instance of **`ac:AudioClip`**,\
  \ a subclass of `ac:AudioManifestation`, is any audio segment that has been published\
  \ in some form or uploaded for consumption, for example, a track in a music label's\
  \ repository or a sound in an audio repository, library or archive.\n\nThe class\
  \ **`ac:AudioCollection`**, another subclass of `ac:AudioManifestation`, is used\
  \ to represent collections of audio clips. The class **`ac:AudioCollectionNode`**\
  \ is used to represent single nodes of a collection, offering local information\
  \ like the index in the collection and pointers to previous and next nodes. The\
  \ separation between the collection node and its actual content (e.g., an `ac:AudioClip`)\
  \ permits the same content to be shared in multiple collections.\n\nThe content\
  \ of each node of a collection is not limited to an `ac:AudioClip`, but may contain\
  \ any `ac:AudioManifestation`. Collections can thus contain other collections to\
  \ support specific cases, e.g. a mapping to the Music Ontology model where an `mo:Release`\
  \ can contain multiple `mo:Record`(s) that can in turn contain multiple `mo:Track`(s).\n\
  ### Items: audio files\n![A diagram showing ac:Item class and related class and\
  \ properties](./img/AC-Ontology-Item.png)\n\nAn `ac:AudioItem` is a concrete exemplar\
  \ of an audio manifestation. In our domain, the main exemplars are the actual audio\
  \ files. \n\nThe corresponding class **`ac:AudioFile`** is a subclass of `ac:AudioItem`.\
  \ It is subclass of `ebu:MediaResource` too and the corresponging properties of\
  \ EBU Core can be used to describe the file (e.g., `ebu:hasEncodingFormat`, `ebu:fileSize`).\n\
  \n### Expressions: audio signals\n![A diagram showing ac:Expression class and related\
  \ class and properties](./img/AC-Ontology-Expression.png)\n\nWhile `ac:AudioFile`\
  \ represents a concrete file encoded in a certain format, **`ac:DigitalSignal`**\
  \ is the representation of the corresponding digital signal. `ac:DigitalSignal`\
  \ is a subclass of `ac:MusicalExpression`. \n\nThe data properties `ac:sampleRate`,\
  \ `ac:bitsPerSample`, and `ac:channels`, associate a signal with its basic features\
  \ specific to digital representations.\n\nThe property `ac:publicationOf` can be\
  \ used to associate an `ac:AudioClip` with the corresponding digital signal. The\
  \ property `ac:encodes` instead, associates an `ac:AudioFile` with the encoded digital\
  \ signal.\n\n### Events: recording/syntesis\n![A diagram showing ac:SignalProduction\
  \ class and related class and properties!](./img/AC-Ontology-SignalProduction.png)\n\
  \nThe description of temporal events is crucial to formalise and document transitions\
  \ in the workflow of audio production and publication. The class `event:Event` of\
  \ the Event Ontology is thus specialised for specific actions that are interesting\
  \ for the audio domain.\n\nUsing the `event:Event` class, details of an event such\
  \ as its location in time and space, its factor and its products may be explicitly\
  \ described. Moreover, events can be composed using the property `event:sub_event`,\
  \ to build complex events.\n\nThe class `ac:SignalProduction` represents the act\
  \ of producing a `ac:Signal`, which could be either an `ac:AnalogSignal` or a `ac:DigitalSignal`.\
  \ This is complemented by **`ac:Recording`**, representing the process of recording\
  \ a sound (`ac:Sound`) or the product of **`ac:Synthesis`**, in case of artificially\
  \ generated sounds. \n\n### Events (continued): publication\n![A diagram showing\
  \ ac:Publication class and related class and properties!](./img/AC-Ontology-Publication.png)\n\
  \nThe event **`ac:AudioPublication`** represents the public release of a piece of\
  \ work, e.g., the release of a new album by a band.\n\n### Usage Example\n![A diagram\
  \ showing an example of ontology usage!](./img/AC_Example-AudioClip.png)\n\nThe\
  \ figure above shows an example of use of the Audio Commons ontology to represent\
  \ a sound from the Freesound database. For simplicity only the classes `ac:AudioClip`,\
  \ `ac:AudioFile`, and `ac:AudioCategory` are used in this case."
example: AnalogSignal
example_extras: []
homepage: http://www.audiocommons.org/ac-ontology/aco.html
keywords:
- engineering
- nfdi4ing
mappings:
  tib: n0
name: The Audio Commons Ontology
preferred_prefix: tib.n0
prefix: tib.n0
providers: []
publications: []
synonyms: []
uri_format: https://w3id.org/ac-ontology/aco#$1
