An expanded vocder implementation (#1007)

These changes address issue #864

1. Add the appropriate parameters to do band control to the effect
   and make sure they display properly and save properly in the fxp
2. Make the bands tunable and coutnable (although bands must be %4)
   and respond properly to hi and low band frequency.
3. Implement tuning to reset the frequency bands; also
   implement separate tuning through the center and expand
   for the modulator bands.
4. Bind vocoderbands to multiple of 4.

src/common/Parameter.cpp

@@ -565,6 +565,12 @@ void Parameter::set_type(int ctrltype)
       valtype = vt_int;
       val_default.i = 0;
       break;
+   case ct_vocoder_bandcount:
+      val_min.i = 4;
+      val_max.i = 20;
+      valtype = vt_int;
+      val_default.i = 20;
+      break;
    case ct_countedset_percent:
       val_min.f = 0;
       val_max.f = 1;
@@ -630,6 +636,11 @@ void Parameter::bound_value(bool force_integer)
       val.f = 1.0 * intcount / count;
    }
 
+   if( ctrltype == ct_vocoder_bandcount )
+   {
+       val.i = val.i - val.i % 4;
+   }
+
    switch (valtype)
    {
    case vt_float:
@@ -985,6 +996,10 @@ void Parameter::get_display(char* txt, bool external, float ef)
          // FIXME - do better than this of course
          sprintf(txt, "%d", i);
          break;
+      case ct_vocoder_bandcount:
+         // FIXME - do better than this of course
+         sprintf(txt, "%d bands", i);
+         break;
       case ct_oscroute:
          switch (i)
          {

src/common/Parameter.h

@@ -86,6 +86,7 @@ enum ctrltypes
    ct_character,
    ct_sineoscmode,
    ct_countedset_percent, // what % through a counted set are you
+   ct_vocoder_bandcount,
    num_ctrltypes,
 };
 

src/common/dsp/effect/Effect.cpp

@@ -41,7 +41,10 @@ Effect::Effect(SurgeStorage* storage, FxStorage* fxdata, pdata* pd)
    this->pd = pd;
    ringout = 10000000;
    for (int i = 0; i < n_fx_params; i++)
+   {
       f[i] = &pd[fxdata->p[i].id].f;
+      pdata_ival[i] = &pd[fxdata->p[i].id].i;
+   }
 }
 
 bool Effect::process_ringout(float* dataL, float* dataR, bool indata_present)

src/common/dsp/effect/Effect.h

@@ -78,6 +78,7 @@ class alignas(16) Effect
    pdata* pd;
    int ringout;
    float* f[n_fx_params];
+   int* pdata_ival[n_fx_params]; // f is not a great choice for a member name, but 'i' woudl be worse!
 };
 
 Effect* spawn_effect(int id, SurgeStorage* storage, FxStorage* fxdata, pdata* pd);

src/common/dsp/effect/VocoderEffect.cpp

@@ -32,6 +32,7 @@ VocoderEffect::VocoderEffect(SurgeStorage* storage, FxStorage* fxdata, pdata* pd
    mVoicedLevel = 0.f;
    mUnvoicedLevel = 0.f;*/
 
+   active_bands = n_vocoder_bands;
    mGain.set_blocksize(BLOCK_SIZE);
 
    for (int i = 0; i < NVocoderVec; i++)
@@ -56,22 +57,70 @@ void VocoderEffect::init()
 
 void VocoderEffect::setvars(bool init)
 {
-   float Freq[4];
+   float Freq[4], FreqM[4];
 
    const float Q = 20.f * (1.f + 0.5f * *f[KQuality]);
    const float Spread = 0.4f / Q;
 
-   for (int i = 0; i < n_vocoder_bands; i++)
-   {
-      Freq[i & 3] = vocoder_freq_vsm201[i] * samplerate_inv;
+   active_bands = *pdata_ival[kNumBands];
+   active_bands = active_bands - ( active_bands % 4 ); // FIXME - adjust the UI to be chunks of 4
+#if 0
+   std::cout << "ACtivet bands is " << active_bands << std::endl;
+
+   std::cout << "Freq Low is " << *f[kFreqLo] << " " << 440.f * pow(2.f, *f[kFreqLo]/12.f) << std::endl;
+   std::cout << "Freq High is " << *f[kFreqHi] << std::endl;
+#endif
+   float flo = *f[kFreqLo];
+   float fhi = *f[kFreqHi];
+   float df = (fhi-flo)/(active_bands-1);
+
+   float hzlo = 440.f * pow(2.f, flo / 12.f );
+   float dhz = pow(2.f, df / 12.f );
+
+   float fb = hzlo;
 
+   float mb = fb;
+   float mdhz = dhz;
+   bool sepMod = false;
+
+   float mC = *f[kModCenter];
+   float mX = *f[kModExpand];
+
+   if( mC != 0 || mX != 0 )
+   {
+       sepMod = true;
+       auto fDist = fhi - flo;
+       auto fDistHalf = fDist / 2.f;
+       auto mMid = fDistHalf + flo + 0.3 * mC * fDistHalf; // that 0.3 is a tuning choice about how far we can move center
+       auto mLo = mMid - fDistHalf * ( 1 + 0.7 * mX ); // as is that 0.7
+       auto dM = fDistHalf * 2 * ( 1.0 + 0.7 * mX ) / (active_bands - 1);
+
+       mb = 440.0 * pow(2.f, mLo / 12.f );
+       mdhz = pow( 2.f, dM / 12.f );
+   }
+
+   for (int i = 0; i < active_bands && i < n_vocoder_bands; i++)
+   {
+       //std::cout << "vsm201[" << i << "]=" << vocoder_freq_vsm201[i] << "  fb=" << fb << std::endl;
+      Freq[i & 3] = fb * samplerate_inv;
+      FreqM[i & 3] = mb * samplerate_inv;
+
       if ((i & 3) == 3)
       {
          int j = i >> 2;
          mCarrierL[j].SetCoeff(Freq, Q, Spread);
          mCarrierR[j].CopyCoeff(mCarrierL[j]);
-         mModulator[j].CopyCoeff(mCarrierL[j]);
+         if( sepMod )
+         {
+             mModulator[j].SetCoeff(FreqM, Q, Spread);
+         }
+         else
+         {
+             mModulator[j].CopyCoeff(mCarrierL[j]);
+         }
       }
+      fb *= dhz;
+      mb *= mdhz;
    }
 
    /*	mVoicedDetect.coeff_LP(biquadunit::calc_omega_from_Hz(1000.f), 0.707);
@@ -147,7 +196,7 @@ void VocoderEffect::process(float* dataL, float* dataR)
       vFloat LeftSum = vZero;
       vFloat RightSum = vZero;
 
-      for (int j = 0; j < (NVocoderVec); j++)
+      for (int j = 0; j < (active_bands >> 2) && j < ( n_vocoder_bands >> 2 ) /*(NVocoderVec)*/; j++)
       {
          vFloat Mod = mModulator[j].CalcBPF(In);
          Mod = vMin(vMul(Mod, Mod), MaxLevel);
@@ -180,6 +229,17 @@ void VocoderEffect::init_default_values()
    fxdata->p[KGateLevel].val.f = -96.f;
    fxdata->p[KRate].val.f = 0.f;
    fxdata->p[KQuality].val.f = 0.f;
+
+   fxdata->p[kNumBands].val.i = n_vocoder_bands;
+
+   // freq = 440 * 2^(v/12)
+   // log(freq/440)/log(2) = v/12
+   // 12 * log(freq/440) / log(2) = v;
+   fxdata->p[kFreqLo].val.f = 12.f * log(vocoder_freq_vsm201[0]/440.f)/log(2.f);
+   fxdata->p[kFreqHi].val.f = 12.f * log(vocoder_freq_vsm201[n_vocoder_bands-1]/440.f)/log(2.f);
+
+   fxdata->p[kModExpand].val.f = 0.f;
+   fxdata->p[kModCenter].val.f = 0.f;
 }
 
 //------------------------------------------------------------------------------------------------
@@ -192,6 +252,8 @@ const char* VocoderEffect::group_label(int id)
       return "Levels";
    case 1:
       return "Filterbank";
+   case 2:
+       return "Bands";
    }
    return 0;
 }
@@ -206,6 +268,8 @@ int VocoderEffect::group_label_ypos(int id)
       return 1;
    case 1:
       return 7;
+   case 2:
+       return 13;
    }
    return 0;
 }
@@ -235,6 +299,27 @@ void VocoderEffect::init_ctrltypes()
    fxdata->p[KQuality].set_name("Q");
    fxdata->p[KQuality].set_type(ct_percent_bidirectional);
    fxdata->p[KQuality].posy_offset = 3;
+
+   fxdata->p[kNumBands].set_name("# Bands");
+   fxdata->p[kNumBands].set_type(ct_vocoder_bandcount);
+   fxdata->p[kNumBands].posy_offset = 3;
+
+   fxdata->p[kFreqLo].set_name("Low band");
+   fxdata->p[kFreqLo].set_type(ct_freq_audible);
+   fxdata->p[kFreqLo].posy_offset = 3;
+
+   fxdata->p[kFreqHi].set_name("High band");
+   fxdata->p[kFreqHi].set_type(ct_freq_audible);
+   fxdata->p[kFreqHi].posy_offset = 3;
+
+   fxdata->p[kModExpand].set_name("Mod XPand");
+   fxdata->p[kModExpand].set_type(ct_percent_bidirectional);
+   fxdata->p[kModExpand].posy_offset = 3;
+
+   fxdata->p[kModCenter].set_name("Mod Center");
+   fxdata->p[kModCenter].set_type(ct_percent_bidirectional);
+   fxdata->p[kModCenter].posy_offset = 3;
+
 }
 
 //------------------------------------------------------------------------------------------------

src/common/dsp/effect/effect_defs.h

@@ -278,6 +278,12 @@ class VocoderEffect : public Effect
       // KUnvoicedThreshold,
       KQuality,
       KShift,
+
+      kNumBands,
+      kFreqLo,
+      kFreqHi,
+      kModExpand,
+      kModCenter,
    };
 
    VocoderEffect(SurgeStorage* storage, FxStorage* fxdata, pdata* pd);
@@ -307,7 +313,8 @@ class VocoderEffect : public Effect
    lipol_ps mGain alignas(16);
 
    int mBI; // block increment (to keep track of events not occurring every n blocks)
-
+   int active_bands;
+
    /*
    float mVoicedLevel;
    float mUnvoicedLevel;