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X3DAUDIO_DSP_SETTINGS structure (x3daudio.h)

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Receives the results from a call to X3DAudioCalculate.

Syntax

typedef struct X3DAUDIO_DSP_SETTINGS {
  FLOAT32 *pMatrixCoefficients;
  FLOAT32 *pDelayTimes;
  UINT32  SrcChannelCount;
  UINT32  DstChannelCount;
  FLOAT32 LPFDirectCoefficient;
  FLOAT32 LPFReverbCoefficient;
  FLOAT32 ReverbLevel;
  FLOAT32 DopplerFactor;
  FLOAT32 EmitterToListenerAngle;
  FLOAT32 EmitterToListenerDistance;
  FLOAT32 EmitterVelocityComponent;
  FLOAT32 ListenerVelocityComponent;
} X3DAUDIO_DSP_SETTINGS, *LPX3DAUDIO_DSP_SETTINGS;

Members

pMatrixCoefficients

Caller provided array that will be initialized with the volume level of each source channel present in each destination channel. The array must have at least (SrcChannelCount × DstChannelCount) elements. The array is arranged with the source channels as the column index of the array and the destination channels as the row index of the array. For example, when rendering two-channel stereo input into 5.1 output that is weighted toward the front channels—but is absent from the center and low-frequency channels—the matrix might be as shown in the following table.

Output Left Input Right Input
Left 1.0 0.0
Right 0.0 1.0
Front Center 0.0 0.0
LFE 0.0 0.0
Rear Left 0.8 0.0
Rear Right 0.0 0.8
 

Note that the left and right channels are fully mapped to the output left and right channels; 80 percent of the left and right input is mapped to the rear left and right channels.

The pMatrixCoefficients member can be NULL if the X3DAUDIO_CALCULATE_MATRIX flag is not specified when calling X3DAudioCalculate.

When using X3DAudio with XAudio2 the value returned in the pMatrixCoefficients member would be applied to a voice with IXAudio2Voice::SetOutputMatrix.

pDelayTimes

Caller provided delay time array, which receives delays for each destination channel in milliseconds. This array must have at least DstChannelCount elements. X3DAudio doesn't actually perform the delay. It simply returns the coefficients that may be used to adjust a delay DSP effect placed in the effect chain. The pDelayTimes member can be NULL if the X3DAUDIO_CALCULATE_DELAY flag is not specified when calling X3DAudioCalculate.

Note  This member is only returned when X3DAudio is initialized for stereo output. For typical Xbox 360 usage, it will not return any data at all.
 

SrcChannelCount

Number of source channels. This must be initialized to the number of emitter channels before calling X3DAudioCalculate.

DstChannelCount

Number of source channels. This must be initialized to the number of emitter channels before calling X3DAudioCalculate.

LPFDirectCoefficient

LPF direct-path coefficient. Only calculated if the X3DAUDIO_CALCULATE_LPF_DIRECT flag is specified when calling X3DAudioCalculate.

When using X3DAudio with XAudio2 the value returned in the LPFDirectCoefficient member would be applied to a low pass filter on a source voice with IXAudio2Voice::SetFilterParameters.

LPFReverbCoefficient

LPF reverb-path coefficient.

Only calculated if the X3DAUDIO_CALCULATE_LPF_REVERB flag is specified when calling X3DAudioCalculate.

ReverbLevel

Reverb send level. Only calculated if the X3DAUDIO_CALCULATE_REVERB flag is specified when calling X3DAudioCalculate.

DopplerFactor

Doppler shift factor. Scales the resampler ratio for Doppler shift effect, where:

effective_frequency = DopplerFactor × original_frequency

Only calculated if the X3DAUDIO_CALCULATE_DOPPLER flag is specified when calling X3DAudioCalculate.

When using X3DAudio with XAudio2 the value returned in the DopplerFactor would be applied to a source voice with IXAudio2SourceVoice::SetFrequencyRatio.

EmitterToListenerAngle

Emitter-to-listener interior angle, expressed in radians with respect to the emitter's front orientation.

Only calculated if the X3DAUDIO_CALCULATE_EMITTER_ANGLE flag is specified when calling X3DAudioCalculate.

EmitterToListenerDistance

Distance in user-defined world units from the listener to the emitter base position.

EmitterVelocityComponent

Component of emitter velocity vector projected onto emitter-to-listener vector in user-defined world units per second.

Only calculated if the X3DAUDIO_CALCULATE_DOPPLER flag is specified when calling X3DAudioCalculate.

ListenerVelocityComponent

Component of listener velocity vector projected onto the emitter->listener vector in user-defined world units per second. Only calculated if the X3DAUDIO_CALCULATE_DOPPLER flag is specified when calling X3DAudioCalculate.

Remarks

The following members must be initialized before passing this structure to the X3DAudioCalculate function:

  • pMatrixCoefficients

  • pDelayTimes
  • SrcChannelCount

  • DstChannelCount
The following members are returned by passing this structure to the X3DAudioCalculate function:
  • pMatrixCoefficients

  • pDelayTimes

  • LPFDirectCoefficient

  • LPFReverbCoefficient
  • ReverbLevel

  • DopplerFactor

  • EmitterToListenerAngle
  • EmitterToListenerDistance

  • EmitterVelocityComponent

  • ListenerVelocityComponent
Note  For pMatrixCoefficients and pDelayTimes, X3DAudioCalculate does not allocate additional memory. X3DAudioCalculate merely modifies the values at the memory locations allocated for these pointers.
 

Platform Requirements

Windows 10 (XAudio2.9); Windows 8, Windows Phone 8 (XAudio 2.8); DirectX SDK (XAudio 2.7)

Requirements

Requirement Value
Header x3daudio.h

See also

Structures