MultiChannelSpectralNode.h

MultiChannelSpectralNode.h

#include "cinder/audio/audio.h"

//class for getting individual channel data

typedef std::shared_ptr<class MultiChannelSpectralNode>	MultiChannelSpectralNodeRef;

class MultiChannelSpectralNode : public cinder::audio::MonitorNode {
public:
    struct Format : public ci::audio::MonitorNode::Format {
        Format() : ci::audio::MonitorNode::Format(), mFftSize( 0 ), mWindowType( ci::audio::dsp::WindowType::BLACKMAN ) {}
        
        Format&     fftSize( size_t size )                          { mFftSize = size; return *this; }
        Format&		windowType( ci::audio::dsp::WindowType type )	{ mWindowType = type; return *this; }
        Format&		windowSize( size_t size )                       { ci::audio::MonitorNode::Format::windowSize( size ); return *this; }
        size_t		getFftSize() const                              { return mFftSize; }
        ci::audio::dsp::WindowType	getWindowType() const			{ return mWindowType; }
        Format&		channels( size_t ch )                           { ci::audio::Node::Format::channels( ch ); return *this; }
        Format&		channelMode( ChannelMode mode )                 { ci::audio::Node::Format::channelMode( mode ); return *this; }
        Format&		autoEnable( bool autoEnable = true )            { ci::audio::Node::Format::autoEnable( autoEnable ); return *this; }
        
    protected:
        size_t                      mFftSize;
        ci::audio::dsp::WindowType	mWindowType;
    };
    
    MultiChannelSpectralNode( const Format &format = Format() );
    virtual ~MultiChannelSpectralNode();
    
    void    prepareProcessing();
    const	std::vector<float>& getMagSpectrum(size_t channel);
    float	getSpectralCentroid(size_t channel);
    
    size_t	getNumBins() const				{ return mFftSize / 2; }
    size_t	getFftSize() const				{ return mFftSize; }
    float	getFreqForBin( size_t bin );
    float	getSmoothingFactor() const		{ return mSmoothingFactor; }
    void	setSmoothingFactor( float factor );
    
protected:
    void initialize() override;
    
private:
    std::unique_ptr<ci::audio::dsp::Fft>	mFft;
    ci::audio::Buffer                       mFftBuffer;			// windowed samples before transform
    ci::audio::BufferSpectral				mBufferSpectral;	// transformed samples
    std::vector<std::vector<float>>         mMagSpectrum;		// computed magnitude spectrum from frequency-domain samples
    ci::audio::AlignedArrayPtr				mWindowingTable;
    size_t                                  mFftSize;
    ci::audio::dsp::WindowType				mWindowType;
    float                                   mSmoothingFactor;
    uint64_t                                mLastFrameMagSpectrumComputed;
};