AudioFunctions.eel

/* 
   * Author: EUGEN27771
   * Author URI: http://forum.cockos.com/member.php?u=50462
   * Licence: GPL v3
   * Version: 1.0
   * NoIndex: true
*/

//**************************************************************************************************
//*** Audio functions ******************************************************************************
//**************************************************************************************************
// -- DB2VAL - VAL2DB ----------------------------
function DB2VAL(x)
(
  exp((x)*0.11512925464970228420089957273422);
);
//----------------------------
function VAL2DB(x)
  local(v)
(
  x < 0.0000000298023223876953125 ? (
    -150; 
  ) : (
    v = log(x)*8.6858896380650365530225783783321;
    v < -150 ? -150 : v;
  );
);

//------------------------------------------------
//-- Simple Filter -------------------------------
//------------------------------------------------
function FilterB.SetValues(type, FreqHz, samplerate)
  local(sqr2, c, c2, csqr2, d)
  instance(active, ampIn0, ampIn1, ampIn2, ampOut1, ampOut2,
  dlyIn1, dlyIn2, dlyOut1, dlyOut2) //reset on change    
( 
  // пересмотреть акт. значения. LP тоже не должен заходить в ноль!
  active = (type == 0 && FreqHz < 19999) || (type == 1 && FreqHz > 1);  
  
  active ? (
    type ? (
      // Hi Pass //
      sqr2 = 1.414213562;
      c = tan(($pi/samplerate) * FreqHz );
      c2 = c * c;
      csqr2 = sqr2 * c;
      d = (c2 + csqr2 + 1);
      ampIn0 = 1 / d;
      ampIn1 = -(ampIn0 + ampIn0);
      ampIn2 = ampIn0;
      ampOut1 = (2 * (c2 - 1)) / d;
      ampOut2 = (1 - csqr2 + c2) / d;
    ) : (
      // Low Pass //
      sqr2 = 1.414213562;
      c = 1 / tan(($pi/samplerate) * FreqHz );
      c2 = c * c;
      csqr2 = sqr2 * c;
      d = (c2 + csqr2 + 1);
      ampIn0 = 1 / d;
      ampIn1 = ampIn0 + ampIn0;
      ampIn2 = ampIn0;
      ampOut1 = (2 * (1 - c2)) / d;
      ampOut2 = (c2 - csqr2 + 1) / d;   
    );
  );
  
  // без сброса тянется хвост, на скриптах не подходит!
  dlyIn1 = dlyIn2 = dlyOut1 = dlyOut2 = 0; //reset on change

);

//----------------------------
// Filter in = input sample
// Filter out = out sample
function FilterB.Apply(in)
  instance(active, ampIn0, ampIn1, ampIn2, ampOut1, ampOut2, dlyIn1, dlyIn2, dlyOut1, dlyOut2, out)
(
  out = in;
  active ? (
    out = (ampIn0 * in) + (ampIn1 * dlyIn1) + (ampIn2 * dlyIn2) - (ampOut1 * dlyOut1) - (ampOut2 * dlyOut2);
    dlyOut2 = dlyOut1;
    dlyOut1 = out;
    dlyIn2 = dlyIn1;
    dlyIn1 = in;
  );
  
  out;
);

//------------------------------------------------
// -- RMS follower(Test, need some fixes) --------
//------------------------------------------------
/* for JSFX variant
function RMSFollower.SetValues(buf, rms_size_ms, samplerate)
  local(last_rms_size)
(
  // samplerate can be different from the global srate if need
  // rms_size_ms - max 1000 ms, change if need
  this.buf = buf;
  last_rms_size = this.rms_size;
  this.rms_size = min( max(samplerate*rms_size_ms/1000, 1), samplerate);
  last_rms_size != this.rms_size ? (
      this.rms_sqr_sum = this.rms_bpos = 0;
      memset(this.buf, 0, this.rms_size);
  );
);
*/
// for script
function RMSFollower.SetValues(buf, rms_size_ms, samplerate)
  local(last_rms_size)
(
  // samplerate can be different from the global srate if need
  // rms_size_ms - max 1000 ms, change if need
  this.buf = buf;
  this.rms_size = floor(min(max(samplerate*rms_size_ms/1000, 1), samplerate));
  this.rms_sqr_sum = 0;
  this.rms_bpos = 0;
  memset(this.buf, 0, this.rms_size); // clear
);

//----------------------------------------
function RMSFollower.Apply(in)
  instance(buf, rms_size, rms_sqr_sum, rms_bpos)
(
  rms_sqr_sum = max(rms_sqr_sum - buf[rms_bpos], 0) + (buf[rms_bpos] = sqr(in));
  (rms_bpos+=1) >= rms_size ? rms_bpos=0;
  sqrt(rms_sqr_sum/rms_size); // ret
);

//------------------------------------------------
// -- Env follower -------------------------------
//------------------------------------------------
function EnvFollower.SetValues(attack_ms, release_ms, samplerate)
(
  this.ga = exp(-1/(samplerate*attack_ms/1000));
  this.gr = exp(-1/(samplerate*release_ms/1000));
  this.out = 0;
);

//------------------------------
// Env in = input sample
// Env retval = out = output envelope
function EnvFollower.Apply(in)
  instance(ga, gr, out)
(
  in = abs(in); // abs sample value
  out < in ? out = in + ga*(out-in) : out = in + gr*(out-in); 
);

//------------------------------------------------
// -- Simple Compressor --------------------------
//------------------------------------------------
//thresh_dB = comp threshold
//ratio = X in form X : 1, must be num 1 ... max,
//slope 0 = no compress, 1 = max compression
function CompD.SetValues(thresh_dB, ratio)
(
  this.thresh_dB = thresh_dB;
  this.thresh = 10^(thresh_dB/20);
  this.ratio = ratio;
  this.slope = 1 - 1/ratio; // slope
);

//------------------------------
//Comp env = envelope 
//Comp gain = gain multiplier
//slope прим. к разнице в dB, поэтому преобразования
function CompD.Apply(env)
  instance(thresh_dB, thresh, slope, gain_dB, gain)
(
  gain = 1;
  gain_dB = 0;
  env > thresh ? (
    gain_dB = slope * (thresh_dB - VAL2DB(env));
    gain = DB2VAL(gain_dB);
  ); 
  gain; // comp out gain
);