BassTrebleBase.cpp

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/**********************************************************************
 
   Audacity: A Digital Audio Editor
   Audacity(R) is copyright (c) 1999-2016 Audacity Team.
   License: GPL v2 or later.  See License.txt.
 
   BassTreble.cpp
   Steve Daulton
 
**********************************************************************/
#include "BassTrebleBase.h"
#include "ShuttleAutomation.h"
 
const EffectParameterMethods& BassTrebleBase::Parameters() const
{
   static CapturedParameters<BassTrebleBase, Bass, Treble, Gain, Link>
      parameters;
   return parameters;
}
 
const ComponentInterfaceSymbol BassTrebleBase::Symbol { XO("Bass and Treble") };
 
BassTrebleBase::BassTrebleBase()
{
   SetLinearEffectFlag(true);
}
 
BassTrebleBase::~BassTrebleBase()
{
}
 
// ComponentInterface implementation
 
ComponentInterfaceSymbol BassTrebleBase::GetSymbol() const
{
   return Symbol;
}
 
TranslatableString BassTrebleBase::GetDescription() const
{
   return XO("Simple tone control effect");
}
 
ManualPageID BassTrebleBase::ManualPage() const
{
   return L"Bass_and_Treble";
}
 
// EffectDefinitionInterface implementation
 
EffectType BassTrebleBase::GetType() const
{
   return EffectTypeProcess;
}
 
auto BassTrebleBase::RealtimeSupport() const -> RealtimeSince
{
   return RealtimeSince::After_3_1;
}
 
unsigned BassTrebleBase::Instance::GetAudioInCount() const
{
   return 1;
}
 
unsigned BassTrebleBase::Instance::GetAudioOutCount() const
{
   return 1;
}
 
bool BassTrebleBase::Instance::ProcessInitialize(
   EffectSettings& settings, double sampleRate, ChannelNames)
{
   InstanceInit(settings, mState, sampleRate);
   return true;
}
 
size_t BassTrebleBase::Instance::ProcessBlock(
   EffectSettings& settings, const float* const* inBlock,
   float* const* outBlock, size_t blockLen)
{
   return InstanceProcess(settings, mState, inBlock, outBlock, blockLen);
}
 
bool BassTrebleBase::Instance::RealtimeInitialize(EffectSettings&, double)
{
   SetBlockSize(512);
   mSlaves.clear();
   return true;
}
 
bool BassTrebleBase::Instance::RealtimeAddProcessor(
   EffectSettings& settings, EffectOutputs* pOutputs, unsigned numChannels,
   float sampleRate)
{
   BassTrebleBase::Instance slave(mProcessor);
 
   InstanceInit(settings, slave.mState, sampleRate);
 
   mSlaves.push_back(slave);
 
   return true;
}
 
bool BassTrebleBase::Instance::RealtimeFinalize(EffectSettings&) noexcept
{
   mSlaves.clear();
 
   return true;
}
 
size_t BassTrebleBase::Instance::RealtimeProcess(
   size_t group, EffectSettings& settings, const float* const* inbuf,
   float* const* outbuf, size_t numSamples)
{
   if (group >= mSlaves.size())
      return 0;
   return InstanceProcess(
      settings, mSlaves[group].mState, inbuf, outbuf, numSamples);
}
 
size_t BassTrebleBase::Instance::InstanceProcess(
   EffectSettings& settings, BassTrebleState& data, const float* const* inBlock,
   float* const* outBlock, size_t blockLen)
{
   auto& ms = GetSettings(settings);
 
   const float* ibuf = inBlock[0];
   float* obuf = outBlock[0];
 
   // Set value to ensure correct rounding
   double oldBass = DB_TO_LINEAR(ms.mBass);
   double oldTreble = DB_TO_LINEAR(ms.mTreble);
 
   data.gain = DB_TO_LINEAR(ms.mGain);
 
   // Compute coefficients of the low shelf biquand IIR filter
   if (data.bass != oldBass)
      Coefficients(
         data.hzBass, data.slope, ms.mBass, data.samplerate, kBass, data.a0Bass,
         data.a1Bass, data.a2Bass, data.b0Bass, data.b1Bass, data.b2Bass);
 
   // Compute coefficients of the high shelf biquand IIR filter
   if (data.treble != oldTreble)
      Coefficients(
         data.hzTreble, data.slope, ms.mTreble, data.samplerate, kTreble,
         data.a0Treble, data.a1Treble, data.a2Treble, data.b0Treble,
         data.b1Treble, data.b2Treble);
 
   for (decltype(blockLen) i = 0; i < blockLen; i++)
   {
      obuf[i] = DoFilter(data, ibuf[i]) * data.gain;
   }
 
   return blockLen;
}
 
void BassTrebleBase::Instance::Coefficients(
   double hz, double slope, double gain, double samplerate, int type,
   double& a0, double& a1, double& a2, double& b0, double& b1, double& b2)
{
   double w = 2 * M_PI * hz / samplerate;
   double a = exp(log(10.0) * gain / 40);
   double b = sqrt((a * a + 1) / slope - (pow((a - 1), 2)));
 
   if (type == kBass)
   {
      b0 = a * ((a + 1) - (a - 1) * cos(w) + b * sin(w));
      b1 = 2 * a * ((a - 1) - (a + 1) * cos(w));
      b2 = a * ((a + 1) - (a - 1) * cos(w) - b * sin(w));
      a0 = ((a + 1) + (a - 1) * cos(w) + b * sin(w));
      a1 = -2 * ((a - 1) + (a + 1) * cos(w));
      a2 = (a + 1) + (a - 1) * cos(w) - b * sin(w);
   }
   else // assumed kTreble
   {
      b0 = a * ((a + 1) + (a - 1) * cos(w) + b * sin(w));
      b1 = -2 * a * ((a - 1) + (a + 1) * cos(w));
      b2 = a * ((a + 1) + (a - 1) * cos(w) - b * sin(w));
      a0 = ((a + 1) - (a - 1) * cos(w) + b * sin(w));
      a1 = 2 * ((a - 1) - (a + 1) * cos(w));
      a2 = (a + 1) - (a - 1) * cos(w) - b * sin(w);
   }
}
 
float BassTrebleBase::Instance::DoFilter(BassTrebleState& data, float in)
{
   // Bass filter
   float out = (data.b0Bass * in + data.b1Bass * data.xn1Bass +
                data.b2Bass * data.xn2Bass - data.a1Bass * data.yn1Bass -
                data.a2Bass * data.yn2Bass) /
               data.a0Bass;
   data.xn2Bass = data.xn1Bass;
   data.xn1Bass = in;
   data.yn2Bass = data.yn1Bass;
   data.yn1Bass = out;
 
   // Treble filter
   in = out;
   out = (data.b0Treble * in + data.b1Treble * data.xn1Treble +
          data.b2Treble * data.xn2Treble - data.a1Treble * data.yn1Treble -
          data.a2Treble * data.yn2Treble) /
         data.a0Treble;
   data.xn2Treble = data.xn1Treble;
   data.xn1Treble = in;
   data.yn2Treble = data.yn1Treble;
   data.yn1Treble = out;
 
   return out;
}
 
void BassTrebleBase::Instance::InstanceInit(
   EffectSettings& settings, BassTrebleState& data, float sampleRate)
{
   auto& ms = GetSettings(settings);
 
   data.samplerate = sampleRate;
   data.slope = 0.4f;       // same slope for both filters
   data.hzBass = 250.0f;    // could be tunable in a more advanced version
   data.hzTreble = 4000.0f; // could be tunable in a more advanced version
 
   data.a0Bass = 1;
   data.a1Bass = 0;
   data.a2Bass = 0;
   data.b0Bass = 0;
   data.b1Bass = 0;
   data.b2Bass = 0;
 
   data.a0Treble = 1;
   data.a1Treble = 0;
   data.a2Treble = 0;
   data.b0Treble = 0;
   data.b1Treble = 0;
   data.b2Treble = 0;
 
   data.xn1Bass = 0;
   data.xn2Bass = 0;
   data.yn1Bass = 0;
   data.yn2Bass = 0;
 
   data.xn1Treble = 0;
   data.xn2Treble = 0;
   data.yn1Treble = 0;
   data.yn2Treble = 0;
 
   data.bass = -1;
   data.treble = -1;
   data.gain = DB_TO_LINEAR(ms.mGain);
}
 
bool BassTrebleBase::CheckWhetherSkipEffect(
   const EffectSettings& settings) const
{
   auto& ms = GetSettings(settings);
 
   return (ms.mBass == 0.0 && ms.mTreble == 0.0 && ms.mGain == 0.0);
}