176 lines
4.2 KiB
C
176 lines
4.2 KiB
C
/*****************************************
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EQ10 library version 1.0
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Copyright (C)2002 4Front Technologies
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Written by George Yohng
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http://www.opensound.com
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Proprietary software.
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*****************************************/
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#ifndef EQ10DSP_H_INCLUDED
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#define EQ10DSP_H_INCLUDED
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* used for volume detectors. for instance, if you want to plot
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frequency response, you can use "detect" variable of needed
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subband to query level of that frequency band.
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release time - is the time in seconds in which detector falls back
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to zero, if no peaks detected */
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// #define EQ10_DETECTOR_CODE /* uncomment this to */
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// #define EQ10_DETECTOR_RELEASE 1.0f /* enable band detector */
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/* Dynamic limiter, which prevents EQ from distortion. In no case you
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can overflow EQ and cause it to clip */
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#define EQ10_TRIM_CODE 0.930 /* trim at -0.6dB */
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#define EQ10_TRIM_RELEASE 0.700 /* trim release, in seconds */
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#define EQ10_NOFBANDS 10 /* want more bands? not a problem */
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#define EQ10_Q 1.41 /* global `Q' factor */
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/* if you want separate Q per each band, comment global Q and uncomment
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the following array */
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//#define EQ10_DQ {1.4,1.4,1.4,1.4,1.4,1.4,1.4,1.4,1.4,1.4}
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/* frequency table compatible to Q10 standard */
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typedef
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struct eq10band_s
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{
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double gain; /* gain of current band. Do not use this value,
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use eq10_setgain instead */
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#ifdef EQ10_DETECTOR_CODE
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double detect; /* band detector value, do not use.
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use eq10_detect to read detector value in dB */
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double detectdecay; /* internal - do not use */
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#endif
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double ua0,ub1,ub2; /* internal - do not use */
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double da0,db1,db2; /* internal - do not use */
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double x1,x2,y1,y2; /* internal - do not use */
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} eq10band_t;
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typedef
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struct eq10_s
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{
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double rate; /* sample rate; do not modify */
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/* use eq10_setup to change */
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eq10band_t band[EQ10_NOFBANDS]; /* bands of equalizer */
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double detect; /* global detector value. do not use */
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double detectdecay; /* internal - do not use */
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} eq10_t;
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double eq10_db2gain(double gain_dB); /* converts decibels to internal gain value*/
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double eq10_gain2db(double gain); /* converts internal gain value to decibels*/
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/* prepare eq array for processing,
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eq - pointer to array,
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eqs - number of elements in array (number of audio channels)
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rate - sample rate
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WARNING! this function resets all data in eq and sets all gains to 0dB
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*/
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void eq10_setup(eq10_t *eq, int eqs, double rate);
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/* set band gain */
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/*
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eq - pointer to array,
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eqs - number of elements in array (number of audio channels)
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bandnr - # of band (0...EQ_NOFBANDS-1)
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*/
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void eq10_setgain(eq10_t *eq,int eqs,int bandnr,double gain_dB);
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/* get current band gain */
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/* eq - pointer to element, possible to read gain on each channel
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separately */
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double eq10_getgain(eq10_t *eq,int bandnr);
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/* get detector value */
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/* eq - pointer to element, possible to read detector value on
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each channel separately */
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double eq10_detect(eq10_t *eq,int bandnr);
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/* process function
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eq - pointer to eq structure, corresponding to wanted channel
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buf - input buffer (interleaved multichannel)
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outbuf - output buffer
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sz - number of samples in input buffer
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idx - index of processed channel (0...N-1)
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step - total number of channels in interleaved stream (N)
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*/
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void eq10_processf(eq10_t *eq,float *buf,float *outbuf,int sz,int idx,int step);
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/*
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Example:
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#define NCHAN 6
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...
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eq10_t eq[NCHAN]; // we process 5.1 data, thus 6 channels
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int t;
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eq10_t *peq;
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...
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eq10_setup(eq,NCHAN,44100); // initialize
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...
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eq10_setgain(eq,NCHAN, 5, -10.0f ); // set -10dB for gain6 (nr's from zero)
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...
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while (bla bla bla) // inner loop
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{
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for(t=0, peq=eq; t<NCHAN; t++, peq++)
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{
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eq10_processf(peq, input_buf, output_buf, cSamples, t, NCHAN);
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}
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}
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...
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*/
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#ifdef __cplusplus
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}
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#endif
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#endif //EQ10DSP_H_INCLUDED
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