Initial community commit

Src/Winamp/eq10dsp.h

@@ -0,0 +1,175 @@
+/*****************************************
+
+   EQ10 library version 1.0
+   Copyright (C)2002 4Front Technologies
+   Written by George Yohng
+
+   http://www.opensound.com
+   
+   Proprietary software.
+ 
+ *****************************************/
+
+
+#ifndef EQ10DSP_H_INCLUDED
+#define EQ10DSP_H_INCLUDED
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* used for volume detectors. for instance, if you want to plot
+   frequency response, you can use "detect" variable of needed
+   subband to query level of that frequency band.
+   
+   release time - is the time in seconds in which detector falls back
+   to zero, if no peaks detected */
+
+
+// #define EQ10_DETECTOR_CODE           /* uncomment this to  */
+// #define EQ10_DETECTOR_RELEASE  1.0f  /* enable band detector */
+
+
+/* Dynamic limiter, which prevents EQ from distortion. In no case you 
+   can overflow EQ and cause it to clip */
+
+#define EQ10_TRIM_CODE    0.930  /* trim at -0.6dB */
+#define EQ10_TRIM_RELEASE 0.700  /* trim release, in seconds */
+
+
+#define EQ10_NOFBANDS 10     /* want more bands? not a problem */
+
+#define EQ10_Q        1.41  /* global `Q' factor */
+                                                                                    
+/* if you want separate Q per each band, comment global Q and uncomment
+   the following array */
+
+//#define EQ10_DQ     {1.4,1.4,1.4,1.4,1.4,1.4,1.4,1.4,1.4,1.4}
+
+/* frequency table compatible to Q10 standard */
+
+
+
+
+typedef
+struct eq10band_s
+{
+    double gain;    /* gain of current band. Do not use this value, 
+                      use eq10_setgain instead */
+
+#ifdef EQ10_DETECTOR_CODE
+    double detect;  /* band detector value, do not use. 
+                      use eq10_detect to read detector value in dB */
+
+    double detectdecay;  /* internal - do not use */
+#endif
+
+    double ua0,ub1,ub2;  /* internal - do not use */
+    double da0,db1,db2;  /* internal - do not use */
+    double x1,x2,y1,y2;  /* internal - do not use */
+
+} eq10band_t;
+
+
+typedef
+struct eq10_s
+{
+    double rate;         /* sample rate; do not modify */
+                        /* use eq10_setup to change */
+
+    eq10band_t band[EQ10_NOFBANDS]; /* bands of equalizer */
+
+    double detect;       /* global detector value. do not use */
+    double detectdecay;  /* internal - do not use */
+
+} eq10_t;
+
+
+
+double eq10_db2gain(double gain_dB); /* converts decibels to internal gain value*/
+double eq10_gain2db(double gain);    /* converts internal gain value to decibels*/
+
+
+/* prepare eq array for processing, 
+
+   eq   - pointer to array,
+   eqs  - number of elements in array (number of audio channels)
+   rate - sample rate
+
+   WARNING! this function resets all data in eq and sets all gains to 0dB
+*/
+void eq10_setup(eq10_t *eq, int eqs, double rate);
+
+
+
+/* set band gain */
+/*
+   eq     - pointer to array,
+   eqs    - number of elements in array (number of audio channels)
+   bandnr - # of band (0...EQ_NOFBANDS-1)
+*/
+void eq10_setgain(eq10_t *eq,int eqs,int bandnr,double gain_dB);
+
+
+/* get current band gain */
+/* eq - pointer to element, possible to read gain on each channel
+        separately */
+double eq10_getgain(eq10_t *eq,int bandnr);
+
+
+/* get detector value */
+/* eq - pointer to element, possible to read detector value on 
+        each channel separately */
+double eq10_detect(eq10_t *eq,int bandnr);
+
+
+/* process function
+
+   eq     - pointer to eq structure, corresponding to wanted channel
+   buf    - input buffer (interleaved multichannel)
+   outbuf - output buffer
+   sz     - number of samples in input buffer 
+   idx    - index of processed channel (0...N-1)
+   step   - total number of channels in interleaved stream (N)
+
+*/
+
+void eq10_processf(eq10_t *eq,float *buf,float *outbuf,int sz,int idx,int step);
+
+
+/*
+
+Example:
+
+    #define NCHAN 6
+    
+    ...
+
+    eq10_t eq[NCHAN]; // we process 5.1 data, thus 6 channels
+    int t;
+    eq10_t *peq;
+
+    ...
+
+    eq10_setup(eq,NCHAN,44100); // initialize
+
+    ...
+
+    eq10_setgain(eq,NCHAN, 5, -10.0f ); // set -10dB for gain6 (nr's from zero)
+    ...
+
+    while (bla bla bla) // inner loop
+    {
+        for(t=0, peq=eq; t<NCHAN; t++, peq++)
+        {
+            eq10_processf(peq, input_buf, output_buf, cSamples, t, NCHAN);
+        }
+    }
+
+    ...
+
+*/
+
+#ifdef __cplusplus
+}
+#endif
+#endif //EQ10DSP_H_INCLUDED