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Wwise SDK 2022.1.17
Advanced Mix Customization Using the Speaker Matrix Callback

Some games have very specific needs in terms of routing and panning, which may not be readily available in Wwise. One way to work around this limitation is to register to the "speaker matrix callback". This callback is called when a voice or a bus is about to be mixed into another bus. From this callback, you can change the global and channel specific level of the voice or bus, thus modifying the mix or panning.

The following example shows how you can register to this callback for a voice. This happens when you post the event that will play this voice.

The callback VoiceCallback illustrates how you can identify the output bus, change the base volume of the voice as it gets mixed into the output bus, and change the panning volumes to simulate a different angle of incidence. AkSpeakerVolumeMatrixCallbackInfo::pContext exposes information relative to the voice, and AkSpeakerVolumeMatrixCallbackInfo::pMixerContext exposes information relative to the bus into which it is mixed (the dry output bus, or an auxiliary send).

The following example shows how you can register to a bus callback. In this case, AkSpeakerVolumeMatrixCallbackInfo::pContext exposes information relative to the bus to which we registered ("My_Bus"), and AkSpeakerVolumeMatrixCallbackInfo::pMixerContext exposes information relative to the bus into which it is mixed, its parent bus (or the next mixing bus in the signal chain).

The next example shows how you can register to a bus to query its metering data.

AK::IAkMixerInputContext * pContext
Context of the current voice/bus about to be mixed into the output bus with specified base volume and...
Definition: AkCallback.h:169
AkGameObjectID gameObjID
Game object ID.
Definition: AkCallback.h:87
virtual AkReal32 GetSpread(AkUInt32 in_uIndex)=0
AkReal32 * pfBaseVolume
Base volume, common to all channels.
Definition: AkCallback.h:167
@ AK_EnableBusMeter_KPower
Enable computation of K-weighted power metering (used as a basis for computing loudness,...
Definition: AkTypes.h:1213
AkChannelConfig outputConfig
Channel configuration of the output bus.
Definition: AkCallback.h:166
AKSOUNDENGINE_API AKRESULT RegisterBusVolumeCallback(AkUniqueID in_busID, AkBusCallbackFunc in_pfnCallback, void *in_pCookie=NULL)
AkUInt32 uNumChannels
Number of channels.
AkChannelConfig inputConfig
Channel configuration of the voice/bus.
Definition: AkCallback.h:165
AkUInt64 AkGameObjectID
Game object ID.
Definition: AkTypes.h:128
const AkVector & OrientationFront() const
Get orientation front vector.
Definition: AkTypes.h:607
const AkVector & OrientationTop() const
Get orientation top vector.
Definition: AkTypes.h:613
AkUInt32 uChannelMask
Channel mask (configuration).
AkMeteringFlags
Metering flags. Used for specifying bus metering, through AK::SoundEngine::RegisterBusVolumeCallback(...
Definition: AkTypes.h:1207
AkForceInline AkUInt32 GetRequiredSize(AkUInt32 in_uNumChannelsIn, AkUInt32 in_uNumChannelsOut)
Compute size (in bytes) required for given channel configurations.
AK::IAkMixerPluginContext * pMixerContext
Output mixing bus context. Use it to access a few useful panning and mixing services,...
Definition: AkCallback.h:170
AkCallbackType
Type of callback. Used as a bitfield in methods AK::SoundEngine::PostEvent() and AK::SoundEngine::Dyn...
Definition: AkCallback.h:48
float AkReal32
32-bit floating point
virtual AKRESULT GetGameObjectPosition(AkUInt32 in_uIndex, AkSoundPosition &out_position) const =0
AkUniqueID eventID
Unique ID of Event, passed to PostEvent()
Definition: AkCallback.h:97
virtual IAkVoicePluginInfo * GetVoiceInfo()=0
AkReal32 * VectorPtr
Volume vector. Access each element with the standard bracket [] operator.
AkReal32 Y
Y Position.
Definition: AkTypes.h:468
AkUInt32 AkUniqueID
Unique 32-bit ID.
Definition: AkTypes.h:120
virtual AkReal32 GetFocus(AkUInt32 in_uIndex)=0
AkReal32 X
X Position.
Definition: AkTypes.h:467
AkForceInline VectorPtr GetChannel(MatrixPtr in_pVolumeMx, AkUInt32 in_uIdxChannelIn, AkUInt32 in_uNumChannelsOut)
Get pointer to volume distribution for input channel in_uIdxChannelIn.
@ AK_EnableBusMeter_TruePeak
Enable computation of true peak metering (most CPU and memory intensive).
Definition: AkTypes.h:1210
#define AK_SPEAKER_SETUP_3STEREO
3.0 setup channel mask
virtual AkUInt32 GetNum3DPositions()=0
#define AKASSERT(Condition)
Definition: AkAssert.h:67
#define AkAlloca(_size_)
Stack allocations.
AkReal32 Z
Z Position.
Definition: AkTypes.h:469
void SetOrientation(const AkVector &in_orientationFront, const AkVector &in_orientationTop)
Set orientation. Orientation front and top should be orthogonal and normalized.
Definition: AkTypes.h:679
AKSOUNDENGINE_API AKRESULT RegisterBusMeteringCallback(AkUniqueID in_busID, AkBusMeteringCallbackFunc in_pfnCallback, AkMeteringFlags in_eMeteringFlags, void *in_pCookie=NULL)
AkReal32 * pfEmitterListenerVolume
Emitter-listener pair-specific gain. When there are multiple emitter-listener pairs,...
Definition: AkCallback.h:168
virtual AKRESULT Compute3DPositioning(AkReal32 in_fAngle, AkReal32 in_fElevation, AkReal32 in_fSpread, AkReal32 in_fFocus, AkChannelConfig in_inputConfig, AkChannelMask in_uInputChanSel, AkChannelConfig in_outputConfig, AkReal32 in_fCenterPerc, AK::SpeakerVolumes::MatrixPtr out_mxVolumes)=0
Struct containing metering information about a buffer. Depending on when this struct is generated,...
Definition: AkCommonDefs.h:203
static const AkPlayingID AK_INVALID_PLAYING_ID
Invalid playing ID.
Definition: AkTypes.h:165
virtual AKRESULT ComputeSpeakerVolumesDirect(AkChannelConfig in_inputConfig, AkChannelConfig in_outputConfig, AkReal32 in_fCenterPerc, AK::SpeakerVolumes::MatrixPtr out_mxVolumes)=0
AKSOUNDENGINE_API AkUInt32 GetIDFromString(const char *in_pszString)
virtual IAkGameObjectPluginInfo * GetGameObjectInfo()=0
AkForceInline void SetStandard(AkUInt32 in_uChannelMask)
Set channel config as a standard configuration specified with given channel mask.
AkReal32 * MatrixPtr
Volume matrix. Access each input channel vector with AK::SpeakerVolumes::Matrix::GetChannel().
virtual AkReal32 GetCenterPerc()=0
uint32_t AkUInt32
Unsigned 32-bit integer.
Game object information available to plugins.
Definition: IAkPlugin.h:100
3D vector for some operations in 3D space. Typically intended only for localized calculations due to ...
Definition: AkTypes.h:425
AKSOUNDENGINE_API AkPlayingID PostEvent(AkUniqueID in_eventID, AkGameObjectID in_gameObjectID, AkUInt32 in_uFlags=0, AkCallbackFunc in_pfnCallback=NULL, void *in_pCookie=NULL, AkUInt32 in_cExternals=0, AkExternalSourceInfo *in_pExternalSources=NULL, AkPlayingID in_PlayingID=AK_INVALID_PLAYING_ID)
@ AK_SpeakerVolumeMatrix
Callback triggered at each frame, letting the client modify the speaker volume matrix....
Definition: AkCallback.h:54
AK::SpeakerVolumes::MatrixPtr pVolumes
Pointer to volume matrix describing the contribution of each source channel to destination channels....
Definition: AkCallback.h:164
Position and orientation of objects in a "local" space.
Definition: AkTypes.h:594
AkUInt32 AkPlayingID
Playing ID.
Definition: AkTypes.h:123
AkPlayingID playingID
Playing ID of Event, returned by PostEvent()
Definition: AkCallback.h:96
const AkReal32 * ConstVectorPtr
Constant volume vector. Access each element with the standard bracket [] operator.

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