Skip to main content

VR Sound API 2026 R1

Messages List

Last update: 09.03.2026

There are 3 types of messages:

  • The control messages, corresponding to a global instruction, such as initialization.
  • The event service messages, such as the loading or triggering of a sound source.
  • The recurrent service messages sent periodically, corresponding to updates of the listener position or the sources positions.

Control Messages

Keyword Data Comments
GLOBAL_3D_MODE Rendering Mode (string) The rendering modes are:
Binaural
VBAP
Transaural
DoubleTransaural
Ambisonic
API_COORDINATES_MODE Coordinate Mode (string) The available coordinate modes are:
A - Virtools/Unity
B - Polhemus
C - Angular mode

Event Service Messages

Keyword Data Comments
SOUND_LOAD Sound ID (int, from 0 to 32765) Preload a sound file and assign it the specified ID as a reference for later use

File name (string)

Full path of the sound file including extension
SOUND_PLAY_3D Source ID (int, from 0 to 20) Play the 3D sound source identified by the specified ID
Sound ID (int) ID of the preloaded sound (message SOUND_LOAD) that should be played as this sound source
Number of playback loops (int) Number of playback loops: -1 means infinite loop
Volume (float, gain in dB) Initial volume

x (float)

y (float)

z (float)

Initial position of the source
INTERP_SOUND_PLAY Source ID (int, from 1 to 10) Play the 3D interpolated sound source identified by the specified ID
Volume (float, gain in dB) Initial volume

x (float)

y (float)

z (float)

Initial position of the source
Spat (int 0/1) Spatialization off/on
Tracker (int 0/1) Tracking off/on
Solo (int 0/1) Solo off/on
Mute (int 0/1) Mute off/on
SOUND_PLAY_AMBIANCE Source ID (int, from 1 to 2) Play the ambiance sound source identified by the specified ID
Sound ID (int) ID of the preloaded sound (message SOUND_LOAD) that should be played as this sound source
Number of playback loops (int) Number of playback loops: -1 means infinite loop
Volume (float, gain in dB) Initial volume
Solo (int 0/1) Solo off/on
Mute (int 0/1) Mute off/on
Speed (float) Playback speed (1 is the normal speed). Changing the values also affects the pitch.
INPUTCHANNEL_SOUND_PLAY Source ID (int, from 1 to 3)

Play the 3D input audio stream identified by the specified ID

Channel index (int) Index of the sound card’s input channel to use as 3D input audio stream
Volume (float, gain in dB) Initial volume

x (float)

y (float)

z (float)

Initial position of the source
Spat (int 0/1) Spatialization off/on
Tracker (int 0/1) Tracking off/on
Solo (int 0/1) Solo off/on
Mute (int 0/1) Mute off/on
SOUND_STOP_3D Source ID (int, from 1 to 20) Stop the playback of the 3D sound source identified by the specified ID
INTERP_SOUND_STOP Source ID (int, from 1 to 10) Stop the playback of the 3D interpolated sound source identified by the specified ID
SOUND_STOP_AMBIANCE Source ID (int, from 1 to 2) Stop the playback of the ambiance sound source identified by the specified ID
INPUTCHANNEL_SOUND_STOP Source ID (int, from 1 to 3) Stop the playback of the 3D input audio stream identified by the specified ID
SOUND_VOLUME_3D

Source ID (int, from 1 to 20)

Volume (float, gain in dB)

Change the sound volume of the 3D sound source identified by the specified ID

0 dB = unitary gain

Maximum gain allowed = 20 dB

INTERP_SOUND_VOLUME

Source ID (int, from 1 to 10)

Volume (float, gain in dB)

Change the sound volume of the 3D interpolated sound source identified by the specified ID

0 dB = unitary gain

Maximum gain allowed = 10 dB

SOUND_VOLUME_AMBIANCE

Source ID (int, from 1 to 2)

Volume (float, gain in dB)

Change the sound volume of the ambiance sound source identified by the specified ID

0 dB = unitary gain

Maximum gain allowed = 20 dB

INPUTCHANNEL_VOLUME

Source ID (int, from 1 to 3)

Volume (float, gain in dB)

Change the sound volume of the 3D input stream identified by the specified ID

0 dB = unitary gain

Maximum gain allowed = 20 dB

SOLO_3D

Source ID (int, from 1 to 20)

Solo info (int 0/1)

When solo is activated (1) for a 3D sound source, all other non-soloed 3D sound sources are muted.
INTERP_SOLO

Source ID (int, from 1 to 10)

Solo info (int 0/1)

When solo is activated (1) for a 3D interpolated sound source, all other non-soloed 3D interpolated sound sources are muted.
SOLO_AMBIANCE

Source ID (int, from 1 to 2)

Solo info (int 0/1)

When solo is activated (1) for an ambiance sound source, all other non-soloed ambiance sound sources are muted.
INPUTCHANNEL_SOLO

Source ID (int, from 1 to 3)

Solo info (int 0/1)

When solo is activated (1) for a 3D input stream, all other non-soloed input streams are muted.
MUTE_3D

Source ID (int, from 1 to 20)

Mute info (int 0/1)

When mute is activated (1) for a 3D sound source, it becomes silent.
INTERP_MUTE

Source ID (int, from 1 to 10)

Mute info (int 0/1)

When mute is activated (1) for a 3D interpolated sound source, it becomes silent.
MUTE_AMBIANCE

Source ID (int, from 1 to 2)

Mute info (int 0/1)

When mute is activated (1) for an ambiance sound source, it becomes silent.
INPUTCHANNEL_MUTE

Source ID (int, from 1 to 3)

Mute info (int 0/1)

When mute is activated (1) for a 3D input stream, it becomes silent.
ACTIVE_SPAT_3D

Source ID (int, from 1 to 20)

Spat info (int 0/1)

For binaural or transaural restitution only. When spatialization is activated (1), the sound can be perceived in 3D.

INTERP_ACTIVE_SPAT

Source ID (int, from 1 to 10)

Spat info (int 0/1)

For binaural or transaural restitution only. When spatialization is activated (1), the sound can be perceived in 3D.

INPUTCHANNEL_ACTIVE_SPAT

Source ID (int, from 1 to 3)

Spat info (int 0/1)

For binaural or transaural restitution only. When spatialization is activated (1), the sound can be perceived in 3D.

ACTIVE_TRACKING_3D

Source ID (int, from 1 to 20)

Head-tracking info (int 0/1)

For binaural restitution only. When head-tracking is activated (1), the apparent source position remains the same however the listener moves their head.

INTERP_ACTIVE_TRACKING

Source ID (int, from 1 to 10)

Head-tracking info (int 0/1)

For binaural restitution only. When head-tracking is activated (1), the apparent source position remains the same however the listener moves their head.

INPUTCHANNEL_ACTIVE_TRACKING

Source ID (int, from 1 to 3)

Head-tracking info (int 0/1)

For binaural restitution only. When head-tracking is activated (1), the apparent source position remains the same however the listener moves their head.

SPEED_3D

Source ID (int, from 1 to 20)

Playback speed (float)

Playback speed for the 3D sound source identified by the specified ID (1 is the normal speed). Changing the value also affects the pitch.

SPEED_AMBIANCE

Source ID (int, from 1 to 2)

Playback speed (float)

Playback speed for the ambiance sound source identified by the specified ID (1 is the normal speed). Changing the value also affects the pitch.

3D_SOURCE_TRAJECTORY

Source ID (int, from 1 to 20)

File name (string)

Load a trajectory for the 3D sound source identified by the specified ID

Full path of the trajectory file including extension

INTERP_TRAJECTORY

Source ID (int, from 1 to 10)

File name (string)

Load a trajectory for the 3D interpolated sound source identified by the specified ID

Full path of the trajectory file including extension

3D_SOURCE_DIFFUSENESS

Source ID (int, from 1 to 20)

Diffuseness value (int, %)

For VBAP rendering mode only.

Specify how diffuse the spatialization of the 3D sound source identified by the specified ID shall be.

0% means the source is not spread, 100% means the source is totally surrounding and diffused over all speakers.

INTERP_SOURCE_DIFFUSENESS

Source ID (int, from 1 to 10)

Diffuseness value (int, %)

For VBAP rendering mode only.

Specify how diffuse the spatialization of the 3D interpolated sound source identified by the specified ID shall be.

0% means the source is not spread, 100% means the source is totally surrounding and diffused over all speakers.

INPUTCHANNEL_SOURCE_DIFFUSENESS

Source ID (int, from 1 to 3)

Diffuseness value (int, %)

For VBAP rendering mode only.

Specify how diffuse the spatialization of the 3D input audio stream identified by the specified ID shall be.

0% means the source is not spread, 100% means the source is surrounding and diffused over all speakers.

INTERP_CONTROL_PARAM

Source ID (int, from 1 to 10)

Control parameter value (int)

Depending on the type of source, the control parameter can be speed, RPM, or any parameter that has an influence on the rendering of the source.

INTERP_CONTROL_PARAMETER_FILE

Source ID (int, from 1 to 10)

FileName (string)

File containing a sequence of control parameters (as above), varying with time.

INTERP_OVERLAP

Source ID (int, from 1 to 10)

Overlap value (int)

This is the overlap value between two adjacent samples, in the same unit as the control parameter.

Recurrent Service Messages

Keyword Data Comments
HEAD_POSITION_3D

x (float)

y (float)

z (float)

Head coordinates

Elevation (float)

Azimuth (float)

Roll (float)

Coordinate Mode A

Head orientation using Euler Angles in radians

Azimuth (float)

Elevation (float)

Roll (float)

Coordinate Mode B

Head orientation using Euler Angles in radians

SOURCE_POSITION_3D

Source ID (int, from 1 to 20)

x (float)

y (float)

z (float)

3D sound source position update

INTERP_SOURCE_POSITION

Source ID (int, from 1 to 10)

x (float)

y (float)

z (float)

3D interpolated sound source position update

INPUTCHANNEL_POSITION

Source ID (int, from 1 to 3)

x (float)

y (float)

z (float)

3D input audio stream position update

Connect with Ansys