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Effects.CustomDspInternalSetFunction method

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Sets the the callback function of the internal custom DSP. The callback of an internal custom DSP is nothing more than a simple function that will receive original WAV PCM sound data to be modified on the fly.


For further details about managing a custom DSP effect refer to the How to manage custom DSP effects section.

For further details about methods related to the use of special effects refer to the Effects COM object.





[Visual Basic]

control.Effects.CustomDspInternalSetFunction (

nIdDsp as Long,

pCallback as Long

) as enumErrorCodes



short control.Effects.CustomDspInternalSetFunction (

long nIdDsp,

long pCallback









Unique identifier of the custom DSP as returned by the Effects.CustomDspInternalLoad method


Pointer to the callback function containing the code that will effectively modify original WAV PCM data. Remember that callback functions must be as fast as possible in order to avoid slowing down overall performances.

A callback function is defined like this:


[Visual Basic ]


Public Sub MyCustomCallback(

ByVal bufferSamples As Long,

ByVal bufferSamplesLength As Long,

ByVal nUserData As Long



[Visual C++]


void MyCustomCallback (

void *bufferSamples,

DWORD bufferSamplesLength,

DWORD nUserData





Pointer to the buffer containing WAV PCM samples to be processed by the DSP in one of the following formats:

8-bit samples are unsigned

16-bit samples are signed

32-bit floating-point samples can range from -1 to +1: note that they are not clipped so they could be outside the mentioned range.


You can instruct the DSP using 32-bit floating-point samples only through the Effects.CustomDspUseFloatSamples method.


The length in bytes of the buffer above


User specific data



Return value






Negative value

An error occurred (see the LastError property for further error details)

enumErrorCodes.ERR_NOERROR (0)

The method call was successful.