ZPlay.GetFFTData Method

Get FFT data for currently playing samples.

Visual Basic

Public Function GetFFTData(ByVal FFTPoints As Integer, ByVal FFTWindow As TFFTWindow, ByRef HarmonicNumber As Integer, ByRef HarmonicFreq() As Integer, ByRef LeftAmplitude() As Integer, ByRef RightAmplitude() As Integer, ByRef LeftPhase() As Integer, ByRef RightPhase() As Integer) As Boolean

Parameters

Parameters	Description
ByVal FFTPoints As Integer	Set this value to specify FFT size. This value must be power of 2.
ByVal FFTWindow As TFFTWindow	Set this value to specify FFT window.
ByRef HarmonicNumber As Integer	Reference to variable receiving number of harmonics returned from FFT analysis. NumberOfHarmonics = (nFFTPoints/2 + 1)
ByRef HarmonicFreq() As Integer	Reference to integer array receiving frequency of each harmonic. User must to allocate memory for this array. Use returned HarmonicNumber value to get number of harmonics.
ByRef LeftAmplitude() As Integer	Reference to integer array receiving amplitude of each harmonic for left channel. Amplitude range is from 0 to about 120 dB. User needs to allocate memory for this array. User must to allocate memory for this array. Use returned HarmonicNumber value to get number of harmonics.
ByRef RightAmplitude() As Integer	Reference to integer array receiving amplitude of each harmonic for right channel. Amplitude range is from 0 to about 120 dB. User must to allocate memory for this array. Use returned HarmonicNumber value to get number of harmonics.
ByRef LeftPhase() As Integer	Reference to integer array receiving phase of each harmonic for left channel. Phase range is from -90 to 90 degrees. User must to allocate memory for this array. Use returned HarmonicNumber value to get number of harmonics.
ByRef RightPhase() As Integer	Reference to integer array receiving phase of each harmonic for right channel. User must to allocate memory for this array. Use returned HarmonicNumber value to get number of harmonics.

Return Values

Return Values	Description
True	All OK.
False	Error. To get error message read here.

Remarks

FFTPoints parameter specifies number of samples for FFT algorithm. This parameter must be power of 2. Larger value produces more harmonics and better frequency resolution. But this needs more processor power to calculate FFT algorithm.

Note: NumOfHarmnics = NumOfFFTPoints/2 + 1

Note: FFT data are fully synchronized with audio data from wave buffer.