Class

• <DRM Sound Instance>

Superclass

• <DRM SEDRIS Abstract Base>

Subclass

• None.

Definition

An instance of this DRM class is a single case of the existence of a <DRM Sound> instance within a given transmittal, including variations or specializations unique to that case. A <DRM Sound Instance> instance can represent environmental audio, region-based audio, or spatialized audio:

1. Environmental audio is audio that is non-localized and non-attenuated. It is constant over the entire environment represented by the transmittal. Environmental audio can be thought of as background sound. This type of audio has no <DRM Location 3D> component, <DRM Perimeter Data> component, or <DRM Sound Volume> component and therefore cannot have a <DRM Fade Range> component.
2. Region-based audio is similar to environment audio, except that it is constant over a two-dimensional region (if it has a <DRM Perimeter Data> component) or a three-dimensional region (if it has a <DRM Sound Volume> component). Region-based audio is non-localized, but it may be attenuated to support fade out at the boundary of the region. (See examples for the <DRM Perimeter Data> class and the <DRM Sound Volume> class).
3. Spatialized audio may be either two-dimensional or three-dimensional. The method of rendering spatialized audio is left to the consuming application. In this case, a <DRM Location 3D> instance is associated with the <DRM Sound Instance> instance, if spatialized audio is desired.

The active_sound_value specifies the default / active state of the given <DRM Sound> instance, where TRUE indicates on and FALSE indicates off. For a <DRM Sound Instance> instance with a <DRM Sound Instance Control Link> component X, the value of the active_sound_value field is obtained from X.

Class diagram

Figure 6.302 — DRM_Sound_Instance

Constraints

• Publishable object

Example(s)

• A <DRM Sound Instance> instance without any components specifies the constant sound of rainfall over the entire environment that is represented by the transmittal.

• Given a <DRM Geometry Model Instance> instance representing a truck, a <DRM Sound Instance> component of the <DRM Geometry Model Instance> instance uses the <DRM Location 3D> instance of the truck for the location of the sound of the truck.

• Given a <DRM Geometry Model Instance> instance representing a fighter jet, a <DRM Sound Instance> component of the <DRM Geometry Model Instance> instance specifies a unique <DRM Location 3D> instance for the audio in order to simulate propagation of sound delay (one hears the audio in a slightly different location than one sees the fighter jet).

• Create a two-stage sound effect for an engine. The stages are “engine crank” and “engine running”. The application sets the <DRM Sound Instance Control Link> components of both <DRM Sound Instance> instances to “on” to start the sound, at which point the crank sound plays for 1,5 seconds, followed by the (looped) engine running sound. The engine running sound continues to play until the application sets the <DRM Sound Instance Control Link> instance for the engine running sound to “off”.

  1. The first <DRM Sound> instance is instantiated by a <DRM Sound Instance> instance with a <DRM Time Interval> component from 0,0 to 1,5 seconds.
  2. The second <DRM Sound> instance is a looped sound, and is instanced by a <DRM Sound Instance> instance with a start delay (using the <DRM Time Interval> instance of 1,5 seconds) and no end time.