read() [2/4]

float erisAudioAnalyzeFFT1024::read ( float  freq_from, float  freq_to, FFTReadRange *  fftRR = NULL  )

inline

Definition at line 203 of file eris_analyze_fft1024.h.

                                                                           {
        //convert f to bin
        float bw;
        float bin_size;
        unsigned int start_bin;
        unsigned int stop_bin;
 
        bw = AUDIO_SAMPLE_RATE_EXACT/2.0/(float)subsample_by;
        bin_size = bw/1024.0f;
        start_bin = (unsigned int)(freq_from / bin_size);
        stop_bin = (unsigned int)(freq_to / bin_size);
        if (start_bin > 511 || stop_bin > 511){
            start_bin = 0;
            stop_bin = 0;
        }
        /*
        Serial.print(F("fft read: "));
        Serial.print(subsample_by);Serial.print(F(","));
        Serial.print(bw);Serial.print(F(","));
        Serial.print(freq_from);Serial.print(F(","));
        Serial.print(freq_to);Serial.print(F(","));
        Serial.print(bin_size);Serial.print(F(","));
        Serial.print(start_bin);Serial.print(F(","));
        Serial.println(stop_bin); 
        */
        if(fftRR){
            fftRR->startBin = start_bin;
            fftRR->stopBin = stop_bin;
            fftRR->startFrequency = freq_from;
            fftRR->stopFrequency = freq_to;
        }
        
        if (freq_to > bw){
            if(fftRR){
                int16_t cqtBin;
                cqtBin = fftRR->cqtBin;
                //memset(&fftRR,0,sizeof(FFTReadRange));
                fftRR->cqtBin = cqtBin;
                fftRR->peakBin=0;       
                fftRR->estimatedFrequency=0;
                fftRR->peakFrequency=0;
                fftRR->peakValue=0;
                fftRR->avgValueFast=0;              //used to calc moving average convergence / divergence (MACD) 
                fftRR->avgValueSlow=0;          //by comparing a short and long moving average; slow transient detection
                fftRR->transientValue=0;            //difference between the peak and fast peak values
            }
            return 0;
        }
 
        float rval = read(start_bin,stop_bin,fftRR);
        if(fftRR){
            
            //from the peak bin calc the freq
            fftRR->peakFrequency = (fftRR->peakBin * bin_size) -  (bin_size/2.0); //center of the fft bin
            if (fftRR->peakFrequency < 0) fftRR->peakFrequency = 0.01;
            float ratio = 1;
            if ((fftRR->peakBin > 1) && (fftRR->peakBin < 510)){
                //from the balance of the side lobes, estimate the actual frequency
                float lobeFrequency = 1;
                if ((output[fftRR->peakBin+1]-output[fftRR->peakBin-1]) > 0.1 && (output[fftRR->peakBin] > 0)){
                    //pos lobe
                    ratio = (output[fftRR->peakBin+1] - output[fftRR->peakBin-1] + output[fftRR->peakBin+1]) / (1.0 * output[fftRR->peakBin]);
                    lobeFrequency = ((fftRR->peakBin+1) * bin_size) - bin_size/2;
                 } else if (output[fftRR->peakBin-1] > 0.1 && (output[fftRR->peakBin] > 0)){ 
                     //neg lobe
                    ratio = (output[fftRR->peakBin-1]-output[fftRR->peakBin+1] + output[fftRR->peakBin-1]) / (1.0 * output[fftRR->peakBin]);
                    lobeFrequency = ((fftRR->peakBin-1) * bin_size)  - bin_size/2;
                 }
                 fftRR->estimatedFrequency = (fftRR->peakFrequency * (1-ratio)) + (lobeFrequency * ratio); 
                 //clamp estimate
                 if (fftRR->estimatedFrequency > fftRR->stopFrequency)fftRR->estimatedFrequency = fftRR->stopFrequency;
                 if (fftRR->estimatedFrequency < fftRR->startFrequency)fftRR->estimatedFrequency = fftRR->startFrequency;
            }
                if (ssr == SS_HIGHFREQ) ratio = 0.5;
                else ratio = 0.995;
                fftRR->avgValueFast = (fftRR->avgValueFast * ratio) + (fftRR->peakValue * (1.0f -ratio));   //used to calc moving average convergence / divergence (MACD) 
                //fftRR->avgValueFast = fftRR->peakValue;
                ratio = 0.285;
                fftRR->avgValueSlow = (fftRR->avgValueSlow * ratio) + (fftRR->avgValueFast * (1.0f -ratio));    //by comparing a short and long moving average; slow transient detection
                if(fftRR->peakValue > fftRR->avgValueFast) fftRR->avgValueFast = (fftRR->avgValueFast/7.0 )+(fftRR->peakValue/3.0);
                if (fftRR->avgValueFast > 0){
                fftRR->transientValue = (fftRR->transientValue  + (fftRR->avgValueFast - fftRR->avgValueSlow)/(0.00001 + fftRR->avgValueFast))* 0.5;
                } else fftRR->transientValue = 0;
                fftRR->transientValue *= 0.95;
                fftRR->avgValueFast *= 0.998;
                fftRR->avgValueSlow *= 0.998;
        }
            
        return rval; 
    }

References cqtBin, read(), SS_HIGHFREQ, ssr, and subsample_by.

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