LPC.h

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//
//  LPC.h -- specification of the classes that perform LPC-based analysis/resynthesis.
//  These use Peter Kabal's libtsp routines (http://WWW.TSP.ECE.McGill.CA) for the heavy lifting.
//  See the copyright notice and acknowledgment of authors in the file COPYRIGHT
//

#ifndef CSL_LPC_H
#define CSL_LPC_H

#include "CSL_Includes.h"

namespace csl {

// File header and ferame srtuct for LPC data files
// This could use SDIF or add chunk types to AIFF files

// File header

typedef struct lpc_header {
    unsigned int keyword;       // magic #, chunk type
    unsigned int filesize;
    float duration;
    unsigned int numframes;
    unsigned int order;
    unsigned int windowSize;
    unsigned int hopSize;
    double preEmphasis;
} CSL_LPC_HEADER;

// Frame header - similar to an MIR database record; holds frame's derived ampl-domain and freq-domain data

typedef struct frame_header {
    unsigned int keyword;
    unsigned int framesize;
    unsigned int order;     // size of LPC refl. coeff. array
    unsigned int windowSize;    // frame/window size
    float rmsamp;           // RMS ampl
    float hifreq;               // hpf energy > 2 kHz
    float lofreq;               // lpf energy < 200 Hz
    float freqest1;         // autocorr freq estimate
    float freqest2;         // HPS freq estimate
    unsigned int zeroes;        // count of zero-crossings
    float smoothfreq;       // smoothed freq estimate
    float noisiness;            // autocorr noise estimate
    float resid;                // LPC residual energy
    float formant1;         // LPC 1st formant
    float formant2;         // LPC 2nd formant
    float centroid;         // spectral centroid
//  float mfccPeak1;            // 1st MFCC peak
//  float mfccPeak2;            // 2nd MFCC peak
    unsigned int MIDIKey;       // MIDI key #
    unsigned int isTransition;  // state flag (note-on, note-off, continuation, plosive, etc.
//  float[order] data;          // LPC data frame - reflection coefficients
} CSL_LPC_FRAME;

#define CSL_LPC_LKEY 0x55120942         // Magic number for files
#define CSL_LPC_FKEY 0x55120943         // Magic number for frames
#define CSL_LPC_MAXPOLES    150         // max pre-allocated frame size
#define CSL_HPS_DEPTH   10              // size of harmonic product spectrum reduction


class LPCAnalyzer : public Effect {
public:
    LPCAnalyzer(UnitGenerator & in, unsigned size = CGestalt::blockSize(), unsigned hopSize = CGestalt::blockSize(), unsigned order = 50);
    ~LPCAnalyzer();
    unsigned windowSize() { return mWindowSize; }
    unsigned hopSize() { return mHopSize; }
    unsigned LPCOrder() { return mLPCOrder; }
    Buffer getCoefficients() { return mLPCCoefficients; }
    Buffer getResidual() { return mLPCResidual; }
    double getError() { return mPredErr; }

    void setFileNames(char * coeff, char * resid);  
    void setPreEmphasis(double factor) { mPreEmphasis = factor; }
    void setBWExpansion(double factor) { mBWExpansion = factor; }
    void closeFiles();                      
    void setOverwrite(bool reuse) { mOverwriteOutput = reuse; }
    void setUseWindow(bool use) { mUseWindow = use; }
    void nextBuffer(Buffer& outputBuffer, unsigned outBufNum) throw (CException);
    
protected:  
    unsigned mWindowSize;               
    unsigned mHopSize;                  
    unsigned mLPCOrder;                 
    double mPredErr;                        
    double mPreEmphasis;                
    double mBWExpansion;                
    bool mOverwriteOutput;              
    bool mUseWindow;                    

    Buffer mTempBuffer;                 
    Buffer mWindowBuffer;               
    Buffer mLPCCoefficients;                
    Buffer mFilterCoefficients;         
    Buffer mFilterInput;                    
    Buffer mPCCoefficients;             
    Buffer mLPCResidual;                    
    
    RingBuffer mRing;                   

    Butter * mLoPass;                   
    Butter * mHiPass;                       
    FFT * mFFT;                         
                            // Output files
    FILE * mCoeffFile;                  
    SoundFile * mResidFile;             
    
};

//  typical BW expansion factor in range 0.996 - 0.990
//      b           BW exp
//      1.000      0
//      0.996     10.2 Hz
//      0.995     12.8 Hz
//      0.994     15.3 Hz
//      0.990     25.6 Hz
//      0.980     51.4 Hz


class LPCFilter : public Effect, public Scalable {
public:
    LPCFilter(UnitGenerator & in, char * lpcFile);
    LPCFilter(UnitGenerator & in, Buffer & lpcData, unsigned size, unsigned hopSize, unsigned order);
    ~LPCFilter();

    unsigned windowSize() { return mWindowSize; }
    unsigned hopSize() { return mHopSize; }
    unsigned LPCOrder() { return mLPCOrder; }
    double deEmphasis() { return mDeEmphasis; }
    
    Envelope * timeEnvelope() { return mTimeEnvelope; }
    void setTimeEnvelope(Envelope * env) { mTimeEnvelope = env; }
    
    void nextBuffer(Buffer& outputBuffer, unsigned outBufNum) throw (CException);   

protected:  
    unsigned mWindowSize;           
    unsigned mHopSize;              
    unsigned mLPCOrder;             
    double mDeEmphasis;
    
    Envelope * mTimeEnvelope;       

    FILE * mLPCFile;                    
    Buffer mLPCBuffer;              

    Buffer mTempBuffer;             

};

}

#endif