ZPlay.GetFFTData Method

Get FFT data for currently playing samples.

Pascal

function GetFFTData(FFTPoints: Integer; FFTWindow: TFFTWindow; out HarmonicNumber: Integer; HarmonicFreq: TDynamicIntegerArray; LeftAmplitude: TDynamicIntegerArray; RightAmplitude: TDynamicIntegerArray; LeftPhase: TDynamicIntegerArray; RightPhase: TDynamicIntegerArray): Boolean;

Parameters

Parameters	Description
FFTPoints: Integer	Set this value to specify FFT size. This value must be power of 2.
FFTWindow: TFFTWindow	Set this value to specify FFT window.
out HarmonicNumber: Integer	Reference to variable receiving number of harmonics returned from FFT analysis. NumberOfHarmonics = (nFFTPoints/2 + 1)
HarmonicFreq: TDynamicIntegerArray	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.
LeftAmplitude: TDynamicIntegerArray	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.
RightAmplitude: TDynamicIntegerArray	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.
LeftPhase: TDynamicIntegerArray	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.
RightPhase: TDynamicIntegerArray	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.