1 Definition 2 Functional Requirements 3 Syntax 4 Semantics

1 Definition

User Command (CAE-UCM) is End User’s data enabling editing and control an Audio or Visual Scene by specifying navigation, remixing, spatial positioning, substitution, motion, and acoustic environment modifications of Audio Objects.

2 Functional Requirements

User Command shall support the following Functional Requirements:

Scene Navigation Changing the position and/or orientation of the end user by specifying a new User Point of View.
Acquire Object Acquire an Object from an the environment or a storage device.
Deliver Object Deliver an Object to an an the environment or a storage device.
Remixing Level (LUFS measured as specified by ITU‑R BS.1770) specifying amplification or attenuation of Audio Objects.
Addition/Removal Adding or removing Audio Objects from the scene.
Object Repositioning Specifying updated spatial positions (Point of View / Spatial Attitude) of Audio Objects.
Object Substitution Replacing Audio Objects or modifying their Qualifiers (e.g., language).
Object Motion Assigning motion attributes to Audio Objects using Spatial Attitude and Acoustic Profile.
Acoustic Environment Modification Changing the acoustic characteristics applied to Audio Objects through Acoustic Profiles.

3 Syntax


https://schemas.mpai.community/CAE3/V1.0/data/UserCommand.json

4 Semantics

Label Description
Header User Command Header, format: “CAE-UCM-Vx.y”.
MInstanceID Identifier of the M-Instance.
UEnvironmentID Identifier of the User Environment.
UserCommandID Identifier of the User Command.
UserCommandTime Timestamp indicating when the command is issued.
UserCommandData Set of Audio Scene editing commands.
– UserPoV Defines the End User’s Point of View (scene navigation).
– LUFS Audio remixing level parameter.
– AddedObjects List of Audio Objects added to the scene.
– RemovedObjects List of Audio Objects removed from the scene.
– MovedObjects Audio Objects with updated spatial positions.
– ChangedObjects Audio Objects with modified qualifiers (e.g., language).
– ModifiedObjects Audio Objects with modified Acoustic Profiles or motion characteristics.
– Acoustic Environment Modification Audio Scene is modified by acting on Acoustic Profile.
DataXMData Data Exchange Metadata describing the User Command instance.
DescrMetadata Descriptive metadata.

5 Conformance Testing

A Data instance conforms with User Command (CAE‑UCM) if:

  1. Its JSON Object validates against the User Command JSON Schema.
  2. Any included JSON Objects validate against their respective JSON Schemas.
  3. All data elements:
    1. Have the specified Data Types.
    2. Conform with the qualifiers defined in their JSON Schemas.

6 Performance Assessment