Table 6.260—DRM_Sound_Instance
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Property |
Description |
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Superclass |
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Class |
· <DRM Sound Instance> |
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Subclass |
· none |
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Definition |
An object of this DRM class specifies a single case of the existence of a <DRM Sound> within a given transmittal, including variations or specialization unique to that case. A <DRM Sound Instance> can represent environmental audio, region-based audio, or spatialized audio: a. Environmental audio is audio that is non-localized and non-attenuated. It is constant over the entire transmittal. Environmental audio can be thought of as "background" sound. It has no <DRM Location 3D>, <DRM Sound Perimeter Data>, or <DRM Sound Volume>. An example would be the constant sound of rainfall over an entire transmittal. b. Region-based audio is similar to environment audio, with the exception that it's constant over either an areal region or three dimensional volume. Region-based audio is non-localized, but it may be attenuated to support fade out at the boundary. (See examples for <DRM Sound Perimeter Data>, <DRM Sound Volume>). c. 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> is associated with the <DRM Sound Instance> if spatialized audio is desired. |
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Example(s) |
· Given a <DRM Geometry Model Instance> of an automobile, a <DRM Sound Instance> for the <DRM Geometry Model Instance> uses the <DRM Location 3D> of the automobile for the location of the audio. · Given a <DRM Geometry Model Instance> of a supersonic airplane, a <DRM Sound Instance> for the <DRM Geometry Model Instance> specifies a unique <DRM Location 3D> for the audio in order to simulate propagation of sound delay (one hears the audio in a slightly different location than one sees the supersonic airplane). · Create a two-stage sound effect for an engine. The stages are "engine crank" and "engine running". a. The first <DRM Sound> is instanced by a <DRM Sound Instance> with a <DRM Time Interval> from 0.0 to 1.5 seconds. b. The second <DRM Sound> is a looped sound, and is instanced by a <DRM Sound Instance> with a start delay (via the <DRM Time Interval> of 1.5 seconds, and no end time. The application would set the <DRM Sound Instance Control Link>s of both <DRM Sound Instance>s to 'on' to start the sound, at which point the crank sound would play for 1.5 seconds, followed by the (looped) engine running sound. The engine running sound would continue to play until the application set the <DRM Sound Instance Control Link>s for the engine running sound to "off". |
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Inherited field elements |
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Field elements |
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Associated to (one-way) (inherited) |
· none |
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Associated to (one-way) |
· one <DRM Sound>2 |
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Associated by (one-way) (inherited) |
· none |
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Associated by (one-way) |
· none |
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Associated with (two-way) (inherited) |
· none |
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Associated with (two-way) |
· none |
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Composed of (two-way) (inherited) |
· none |
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Composed of (two-way) |
· zero or one <DRM Fade Range>3 · zero or one <DRM Location 3D>4 · zero or one <DRM Perimeter Data>5 · zero or one <DRM Sound Instance Control Link> · zero or one <DRM Sound Volume>6 · zero or more <DRM Time Interval> |
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Composed of (two-way metadata) (inherited) |
· none |
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Composed of (two-way metadata) |
· none |
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Component of (two-way) (inherited) |
· none |
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Component of (two-way) |
· zero or more <DRM Feature Hierarchy>s · zero or more <DRM Geometry Hierarchy>s |
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Constraints |
· none |
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Notes |
1 A value of TRUE indicates the sound is on while a value of FALSE indicates the sound is off. This is the default/active state of the sound. 2 The <DRM Sound> being instanced. 3 Used to define the starting distance at which a fade to off should begin and an ending distance at which the fade to off should be complete. The distance in the <DRM Fade Range> is the range to a <DRM Location 3D>, which in turn is the center of a <DRM Perimeter Data>, or the center of a <DRM Sound Volume>. If no <DRM Fade Range> is present, no attenuation is to be performed, which implies instantaneous on/off transitions at the borders of <DRM Perimeter Data> and <DRM Sound Volume>. 4 Used for spatialized audio. 5 Defines an area within which the <DRM Sound> is to be active. 6 Defines a volume within which the <DRM Sound> is to be active. |
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Class diagram |