/home/marsyas/marsyas/src/marsyas/NoiseGate.cpp

/*
** Copyright (C) 1998-2006 George Tzanetakis <gtzan@cs.uvic.ca>
**  
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
** 
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
** 
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software 
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include "NoiseGate.h"

using std::ostringstream;
using namespace Marsyas;

NoiseGate::NoiseGate(mrs_string name):MarSystem("NoiseGate",name)
{
  //type_ = "NoiseGate";
  //name_ = name;

  state_ = 1.0;
  xdprev_ = 0.0;
  alpha_ = 0.0;
  gainsprev_ = 1.0;

    addControls();
}


NoiseGate::~NoiseGate()
{
}


MarSystem* 
NoiseGate::clone() const 
{
  return new NoiseGate(*this);
}

void 
NoiseGate::addControls()
{
  addctrl("mrs_real/thresh", 0.1);
  addctrl("mrs_real/release", 0.5);
  addctrl("mrs_real/rolloff", .130);
  addctrl("mrs_real/at", 0.0001);
  addctrl("mrs_real/rt", 0.130);
  addctrl("mrs_real/slope", 1.0);
}

void
NoiseGate::myUpdate(MarControlPtr sender)
{
    (void) sender;
  MRSDIAG("NoiseGate.cpp - NoiseGate:myUpdate");
  
  setctrl("mrs_natural/onSamples", getctrl("mrs_natural/inSamples"));
  setctrl("mrs_natural/onObservations", getctrl("mrs_natural/inObservations"));
  setctrl("mrs_real/osrate", getctrl("mrs_real/israte"));
  
    //defaultUpdate(); [!]
    inSamples_ = getctrl("mrs_natural/inSamples")->to<mrs_natural>();
  
    xd_.create(inSamples_);
  gains_.create(inSamples_);
}


void 
NoiseGate::myProcess(realvec& in, realvec& out)
{
    mrs_natural t,o;
  //checkFlow(in,out);
  
  mrs_real thresh = getctrl("mrs_real/thresh")->to<mrs_real>();
  mrs_real release = getctrl("mrs_real/release")->to<mrs_real>();
  mrs_real rolloff = getctrl("mrs_real/rolloff")->to<mrs_real>();
  mrs_real at = getctrl("mrs_real/at")->to<mrs_real>();
  mrs_real rt = getctrl("mrs_real/rt")->to<mrs_real>();
  // FIXME This variable is defined but unused.
  // mrs_real slope = getctrl("mrs_real/slope")->to<mrs_real>();
  
    // calculate rolloff, at and rt time
  at = 1 - exp(-2.2/(22050*at));
  rt = 1 - exp(-2.2/(22050*rt));
    
  for (o = 0; o < inObservations_; o++)
    for (t = 0; t < inSamples_; t++)
      {
        // Calculates the current amplitude of signal and incorporates
        // the at and rt times into xd(o,t)     
        alpha_ = fabs(in(o,t)) - xdprev_;
        if (alpha_ < 0)
        {
            alpha_ = 0;
        }
        xdprev_=xdprev_*(1-rt)+at*alpha_;   
        
        if (state_ == 1.0)
          {
          if (xdprev_ < thresh)
            {
            gains_(o,t) = gainsprev_*rolloff;
            state_ = 0.0;
            }
          else
            {
            gains_(o,t) = 1;
            }
          }
        else
          {
            if (xdprev_ < release)
              {
              gains_(o,t) = gainsprev_*rolloff;
              // rolloff time
              }
            else
            if (xdprev_ > release)
              {
              gains_(o,t) = 1.0;
              state_ = 1.0;
              }
            else
              {
              gains_(o,t) = 0.0;
              }
          }             
        
        gainsprev_ = gains_(o,t);
        out(o,t) =  gainsprev_ * in(o,t);
        
      }
}







    

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