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Definition
Functional Requirements
Syntax
Semantics
Conformance Testing
Performance Assessment

1      Definition

Audio Scene Descriptors are a Data Type including the Audio Objects of a scene, their Sub-Scenes, and their arrangement in the Scene. Audio Scene Descriptors may be hierarchical, i.e., they may contain Objects and Audio Scene Descriptors.

2      Functional Requirements

An Audio Scene Descriptors instance must include:

  1. The Audio Scene Descriptors Header.
  2. The ID of the Audio Scene Descriptors instance.
  3. The Space/Time of the Audio Scene Descriptors instance.

An Audio Scene Descriptors instance may include:

  1. The ID of a Virtual Space (M-Instance) where it is or is intended to be located.
  2. The ID of a U-Environment (Real Space) where it is or is intended to be located.
  3. Time when this instance was produced.
  4. Audio Objects in the Audio Scene, each with their Space/Time.
  5. Audio Sub-Scenes in the Audio Scene, each with their Space/Time.
  6. A mixed array of Basic Audio Scene Descriptors and Audio Scene Descriptors.
  7. MPAI-PTF Data Exchange Metadata.
  8. Descriptive Metadata.

3      Syntax

https://schemas.mpai.community/OSD/V1.5/data/AudioSceneDescriptors.json

4      Semantics

Table 1 – Semantics of the Audio Scene Descriptors Data Type

Label
Description
Header Audio Scene Descriptors Header – Standard “OSD‑ASD‑Vx.y”.
MInstanceID Identifier of the M-Instance (Virtual Space) where this Audio Scene is or is intended to be located.
UEnvironmentID Identifier of the U-Environment (Real Space) where this Audio Scene is or is intended to be located.
AudioSceneDescriptorsID Unique identifier of this Audio Scene Descriptors instance.
AudioSceneDescriptorsTime Time this Audio Scene Descriptors instance was produced.
AudioSceneDescriptorsSpaceTime Space/Time where/when this Audio Scene Descriptors instance is located.
AudioObjectCount Number of Audio Objects in the Audio Scene.
AudioObjects[] Set of Audio Objects in the Audio Scene.
    – AudioObjectSpaceTime Space/Time where/when this Audio Object is located within the Audio Scene.
    – ObjectIDOrObject Either the ID of an Audio Object or the Audio Object itself.
SubAudioSceneCount Number of Audio Sub-Scenes in the Audio Scene.
SubAudioScenes[] Set of Audio Sub-Scenes in the Audio Scene.
    – SubAudioSceneSpaceTime Space/Time where/when this Audio Sub-Scene is located within the Audio Scene.
    – SubAudioSceneIDOrSubAudioScene Either the ID of an Audio Sub-Scene or the Audio Sub-Scene itself.
BasicAudioSceneOrAudioScene A mixed array of Basic Audio Scene Descriptors and Audio Scene Descriptors.
DataXMData MPAI-PTF Data Exchange Metadata providing provenance, authorisation, legal, security, and confidence information associated with this Audio Scene Descriptors instance in a trusted data exchange context.
DescrMetadata Human-readable descriptive metadata of the Audio Scene Descriptors instance (plain text, max 2048 characters).

5      Conformance Testing

A Data instance conforms with Audio Scene Descriptors (OSD‑ASD) if:

  1. The Data validates against the Audio Scene Descriptors’ JSON Schema.
  2. All Data in the Audio Scene Descriptors’ JSON Schema:
    1. Have the specified type.
    2. Validate against their JSON Schemas.
    3. Conform with their Data Qualifiers.

6      Performance Assessment

Not part of this specification.

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