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Waveform.PeaksBufferGet method |
  
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Waveform.PeaksBufferGet method |
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Remarks
Fills two buffers with min and max waveform peaks for the given range. The size of each buffer can be obtained with a previous call to the Waveform.PeaksBufferLengthGet method.
Before calling this method it's mandatory performing a previous sound's analysis through a call to the Waveform.AnalyzeFullSound method and waiting its completion through the WaveAnalysisDone event.
For further details about using the embedded Waveform refer to the Waveform object section.
For further details about generating a waveform bitmap of the loaded sound, before starting its playback, refer to the How to obtain the sound's waveform tutorial.
Syntax
[Visual Basic] control.Waveform.PeaksBufferGet ( nPlayer as Integer, nChannel as Integer, nStartPos as Long, nEndPos as Long, bValueInPerc as enumBoolean, pBufferMin as Variant, pBufferMax as Variant, nBufferLength as Long ) as enumErrorCodes |
[C++] short control.Waveform.PeaksBufferGet ( short nPlayer, short nChannel, long nStartPos, long nEndPos, short bValueInPerc, const VARIANT FAR& pBufferMin, const VARIANT FAR& pBufferMax, long nBufferLength ); |
Parameter |
Description |
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nPlayer |
Number representing the zero-based index of the player that will use the waveform. |
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nChannel |
Number representing the audio channel we are interested in. Can be a value between 0 and 7. |
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nStartPos |
Number representing the start position, expressed in milliseconds, where we want to get waveform's peaks. The value 0 represents the sound's beginning. |
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nEndPos |
Number representing the end position, expressed in milliseconds, where we want to get waveform's peaks. The value -1 represents the sound's end. |
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bValueInPerc |
Boolean value that specifies if the given buffers should be filled with values expressed in percentage. Supported values are the following:
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pBufferMin |
Variant parameter containing the pointer to the buffer that, on return from the method call, will contain the min waveform peaks. |
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pBufferMax |
Variant parameter containing the pointer to the buffer that, on return from the method call, will contain the max waveform peaks. |
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nBufferLength |
Length in bytes of the given buffers previously obtained through the Waveform.PeaksBufferLengthGet method. |
Return value
Value |
Meaning |
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Negative value |
An error occurred, check the LastError property value in order to get the error code |
enumErrorCodes.ERR_NOERROR (0) |
The method call was successful |
Samples
Below you can find a couple of samples that demonstrate how to load waveform peaks in Visual Basic 6 and Visual C++ 6.
Visual Basic 6
' memory buffers must be declared as global variables
Dim m_bufferMin() As Integer
Dim m_bufferMax() As Integer
Private Sub Command1_Click()
Erase m_bufferMin
Erase m_bufferMax
' get the size in bytes of the buffers
Dim nBufferLength As Long
Amp3dj1.Waveform.PeaksBufferLengthGet 0, nStartPosInMs, nEndPosInMs, nBufferLength
ReDim m_bufferMin(nBufferLength/2)
ReDim m_bufferMax(nBufferLength/2)
' fill the buffers with peaks data
Amp3dj1.Waveform.PeaksBufferGet 0, 0, nStartPosInMs, nEndPosInMs, BOOL_TRUE, VarPtr(m_bufferMin(0)), VarPtr(m_bufferMax(0)), nBufferLength
End Sub
Visual C++ 6 with MFC
// memory buffers must be declared as global variables
short *m_bufferMin = NULL;
short *m_bufferMax = NULL;
void CMyDialog::OnButton1()
{
if (m_bufferMin != NULL)
delete m_bufferMin;
if (m_bufferMax != NULL)
delete m_bufferMax;
// get the size in bytes of the buffers
long nBufferLength;
m_ctrlActiveDJ.GetWaveform().PeaksBufferLengthGet (0, nStartPosInMs, nEndPosInMs, nBufferLength);
m_bufferMin = new short[nBufferLength/2];
m_bufferMax = new short[nBufferLength/2];
// fill the buffers with peaks data
Amp3dj1.GetWaveform().PeaksBufferGet (0, 0, nStartPosInMs, nEndPosInMs, TRUE, m_bufferMin, m_bufferMax, nBufferLength);
}
