DtmfBase.cpp

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#include "DtmfBase.h"
#include "BasicUI.h"
#include "Prefs.h"
#include <cmath>
 
namespace
{
wxString AllSymbols();
}
 
static const double kFadeInOut =
   250.0; // used for fadein/out needed to remove clicking noise
 
namespace
{
wxString AllSymbols()
{
   wxString symbols;
   for (unsigned int i = 0; i < DtmfBase::kSymbols.size(); ++i)
      symbols += DtmfBase::kSymbols[i];
   return symbols;
}
} // namespace
 
const ComponentInterfaceSymbol DtmfBase::Symbol { XO("DTMF Tones") };
 
DtmfBase::DtmfBase()
{
}
 
DtmfBase::~DtmfBase()
{
}
 
const EffectParameterMethods& DtmfBase::Parameters() const
{
   static CapturedParameters<DtmfBase, Sequence, DutyCycle, Amplitude>
      parameters {
         [](DtmfBase&, EffectSettings& es, DtmfSettings& s, bool updating) {
            if (updating)
            {
               if (
                  s.dtmfSequence.find_first_not_of(AllSymbols()) !=
                  wxString::npos)
                  return false;
               s.Recalculate(es);
            }
            return true;
         },
      };
   return parameters;
}
 
// ComponentInterface implementation
 
ComponentInterfaceSymbol DtmfBase::GetSymbol() const
{
   return Symbol;
}
 
TranslatableString DtmfBase::GetDescription() const
{
   return XO(
      "Generates dual-tone multi-frequency (DTMF) tones like those produced by the keypad on telephones");
}
 
ManualPageID DtmfBase::ManualPage() const
{
   return L"DTMF_Tones";
}
 
// EffectDefinitionInterface implementation
 
EffectType DtmfBase::GetType() const
{
   return EffectTypeGenerate;
}
 
bool DtmfBase::Instance::ProcessInitialize(
   EffectSettings& settings, double sampleRate, ChannelNames)
{
   mSampleRate = sampleRate;
 
   auto& dtmfSettings = GetSettings(settings);
   if (dtmfSettings.dtmfNTones == 0)
   { // Bail if no DTFM sequence.
      using namespace BasicUI;
      // TODO:  don't use mProcessor for this
      ShowMessageBox(
         XO("DTMF sequence empty.\nCheck ALL settings for this effect."),
         MessageBoxOptions {}.IconStyle(Icon::Error));
      return false;
   }
 
   double duration = settings.extra.GetDuration();
 
   // all dtmf sequence durations in samples from seconds
   // MJS: Note that mDuration is in seconds but will have been quantised to the
   // units of the TTC. If this was 'samples' and the project rate was lower
   // than the track rate, extra samples may get created as mDuration may now be
   // > mT1 - mT0; However we are making our best efforts at creating what was
   // asked for.
 
   auto nT0 = (sampleCount)floor(mT0 * mSampleRate + 0.5);
   auto nT1 = (sampleCount)floor((mT0 + duration) * mSampleRate + 0.5);
   numSamplesSequence =
      nT1 - nT0; // needs to be exact number of samples selected
 
   // make under-estimates if anything, and then redistribute the few remaining
   // samples
   numSamplesTone = sampleCount(floor(dtmfSettings.dtmfTone * mSampleRate));
   numSamplesSilence =
      sampleCount(floor(dtmfSettings.dtmfSilence * mSampleRate));
 
   // recalculate the sum, and spread the difference - due to approximations.
   // Since diff should be in the order of "some" samples, a division (resulting
   // in zero) is not sufficient, so we add the additional remaining samples in
   // each tone/silence block, at least until available.
   diff = numSamplesSequence - (dtmfSettings.dtmfNTones * numSamplesTone) -
          (dtmfSettings.dtmfNTones - 1) * numSamplesSilence;
   while (diff > 2 * dtmfSettings.dtmfNTones - 1)
   { // more than one per thingToBeGenerated
      // in this case, both numSamplesTone and numSamplesSilence would change,
      // so it makes sense
      //  to recalculate diff here, otherwise just keep the value we already
      //  have
 
      // should always be the case that dtmfNTones>1, as if 0, we don't even
      // start processing, and with 1 there is no difference to spread (no
      // silence slot)...
      wxASSERT(dtmfSettings.dtmfNTones > 1);
      numSamplesTone += (diff / (dtmfSettings.dtmfNTones));
      numSamplesSilence += (diff / (dtmfSettings.dtmfNTones - 1));
      diff = numSamplesSequence - (dtmfSettings.dtmfNTones * numSamplesTone) -
             (dtmfSettings.dtmfNTones - 1) * numSamplesSilence;
   }
   wxASSERT(diff >= 0); // should never be negative
 
   curSeqPos = -1; // pointer to string in dtmfSequence
   isTone = false;
   numRemaining = 0;
 
   return true;
}
 
size_t DtmfBase::Instance::ProcessBlock(
   EffectSettings& settings, const float* const*, float* const* outbuf,
   size_t size)
{
   auto& dtmfSettings = GetSettings(settings);
   float* buffer = outbuf[0];
   decltype(size) processed = 0;
 
   // for the whole dtmf sequence, we will be generating either tone or silence
   // according to a bool value, and this might be done in small chunks of size
   // 'block', as a single tone might sometimes be larger than the block
   // tone and silence generally have different duration, thus two generation
   // blocks
   //
   // Note: to overcome a 'clicking' noise introduced by the abrupt transition
   // from/to silence, I added a fade in/out of 1/250th of a second (4ms). This
   // can still be tweaked but gives excellent results at 44.1kHz: I haven't
   // tried other freqs. A problem might be if the tone duration is very short
   // (<10ms)... (?)
   //
   // One more problem is to deal with the approximations done when calculating
   // the duration of both tone and silence: in some cases the final sum might
   // not be same as the initial duration. So, to overcome this, we had a
   // redistribution block up, and now we will spread the remaining samples in
   // every bin in order to achieve the full duration: test case was to generate
   // an 11 tone DTMF sequence, in 4 seconds, and with DutyCycle=75%: after
   // generation you ended up with 3.999s or in other units: 3 seconds and 44097
   // samples.
   //
   while (size)
   {
      if (numRemaining == 0)
      {
         isTone = !isTone;
 
         if (isTone)
         {
            curSeqPos++;
            numRemaining = numSamplesTone;
            curTonePos = 0;
         }
         else
         {
            numRemaining = numSamplesSilence;
         }
 
         // the statement takes care of extracting one sample from the diff bin
         // and adding it into the current block until depletion
         numRemaining += (diff-- > 0 ? 1 : 0);
      }
 
      const auto len = limitSampleBufferSize(size, numRemaining);
 
      if (isTone)
      {
         // generate the tone and append
         assert(curSeqPos < dtmfSettings.dtmfNTones);
         MakeDtmfTone(
            buffer, len, mSampleRate, dtmfSettings.dtmfSequence[curSeqPos],
            curTonePos, numSamplesTone, dtmfSettings.dtmfAmplitude);
         curTonePos += len;
      }
      else
      {
         memset(buffer, 0, sizeof(float) * len);
      }
 
      numRemaining -= len;
 
      buffer += len;
      size -= len;
      processed += len;
   }
 
   return processed;
}
 
// EffectDtmf implementation
 
// Updates dtmfNTones, dtmfTone, dtmfSilence, and sometimes duration
// They depend on dtmfSequence, dtmfDutyCycle, and duration
void DtmfSettings::Recalculate(EffectSettings& settings)
{
   auto& extra = settings.extra;
   // remember that dtmfDutyCycle is in range (0.0-100.0)
 
   dtmfNTones = dtmfSequence.length();
 
   if (dtmfNTones == 0)
   {
      // no tones, all zero: don't do anything
      // this should take care of the case where user got an empty
      // dtmf sequence into the generator: track won't be generated
      extra.SetDuration(0.0);
      dtmfTone = 0;
      dtmfSilence = 0;
   }
   else
   {
      if (dtmfNTones == 1)
      {
         // single tone, as long as the sequence
         dtmfTone = extra.GetDuration();
         dtmfSilence = 0;
      }
      else
      {
         // Don't be fooled by the fact that you divide the sequence into
         // dtmfNTones: the last slot will only contain a tone, not ending with
         // silence. Given this, the right thing to do is to divide the sequence
         // duration by dtmfNTones tones and (dtmfNTones-1) silences each sized
         // according to the duty cycle: original division was: slot=mDuration /
         // (dtmfNTones*(dtmfDutyCycle/DutyCycle.max)+(dtmfNTones-1)*(1.0-dtmfDutyCycle/DutyCycle.max))
         // which can be simplified in the one below.
         // Then just take the part that belongs to tone or silence.
         //
         double slot = extra.GetDuration() /
                       ((double)dtmfNTones + (dtmfDutyCycle / 100.0) - 1);
         dtmfTone = slot * (dtmfDutyCycle / 100.0);            // seconds
         dtmfSilence = slot * (1.0 - (dtmfDutyCycle / 100.0)); // seconds
 
         // Note that in the extremes we have:
         // - dutyCycle=100%, this means no silence, so each tone will measure
         // mDuration/dtmfNTones
         // - dutyCycle=0%, this means no tones, so each silence slot will
         // measure mDuration/(NTones-1) But we always count:
         // - dtmfNTones tones
         // - dtmfNTones-1 silences
      }
   }
 
   // `this` is the settings copy in the validator
   // Update the EffectSettings held by the dialog
   DtmfBase::GetSettings(settings) = *this;
}
 
bool DtmfBase::MakeDtmfTone(
   float* buffer, size_t len, float fs, wxChar tone, sampleCount last,
   sampleCount total, float amplitude)
{
   /*
     --------------------------------------------
                 1209 Hz 1336 Hz 1477 Hz 1633 Hz
 
                             ABC     DEF
      697 Hz          1       2       3       A
 
                     GHI     JKL     MNO
      770 Hz          4       5       6       B
 
                     PQRS     TUV     WXYZ
      852 Hz          7       8       9       C
 
                             oper
      941 Hz          *       0       #       D
     --------------------------------------------
     Essentially we need to generate two sin with
     frequencies according to this table, and sum
     them up.
     sin wave is generated by:
      s(n)=sin(2*pi*n*f/fs)
 
     We will precalculate:
        A= 2*pi*f1/fs
        B= 2*pi*f2/fs
 
     And use two switch statements to select the frequency
 
     Note: added support for letters, like those on the keypad
           This support is only for lowercase letters: uppercase
           are still considered to be the 'military'/carrier extra
           tones.
   */
 
   float f1, f2 = 0.0;
   double A, B;
 
   // select low tone: left column
   switch (tone)
   {
   case '1':
   case '2':
   case '3':
   case 'A':
   case 'a':
   case 'b':
   case 'c':
   case 'd':
   case 'e':
   case 'f':
      f1 = 697;
      break;
   case '4':
   case '5':
   case '6':
   case 'B':
   case 'g':
   case 'h':
   case 'i':
   case 'j':
   case 'k':
   case 'l':
   case 'm':
   case 'n':
   case 'o':
      f1 = 770;
      break;
   case '7':
   case '8':
   case '9':
   case 'C':
   case 'p':
   case 'q':
   case 'r':
   case 's':
   case 't':
   case 'u':
   case 'v':
   case 'w':
   case 'x':
   case 'y':
   case 'z':
      f1 = 852;
      break;
   case '*':
   case '0':
   case '#':
   case 'D':
      f1 = 941;
      break;
   default:
      f1 = 0;
   }
 
   // select high tone: top row
   switch (tone)
   {
   case '1':
   case '4':
   case '7':
   case '*':
   case 'g':
   case 'h':
   case 'i':
   case 'p':
   case 'q':
   case 'r':
   case 's':
      f2 = 1209;
      break;
   case '2':
   case '5':
   case '8':
   case '0':
   case 'a':
   case 'b':
   case 'c':
   case 'j':
   case 'k':
   case 'l':
   case 't':
   case 'u':
   case 'v':
      f2 = 1336;
      break;
   case '3':
   case '6':
   case '9':
   case '#':
   case 'd':
   case 'e':
   case 'f':
   case 'm':
   case 'n':
   case 'o':
   case 'w':
   case 'x':
   case 'y':
   case 'z':
      f2 = 1477;
      break;
   case 'A':
   case 'B':
   case 'C':
   case 'D':
      f2 = 1633;
      break;
   default:
      f2 = 0;
   }
 
   // precalculations
   A = B = 2 * M_PI / fs;
   A *= f1;
   B *= f2;
 
   // now generate the wave: 'last' is used to avoid phase errors
   // when inside the inner for loop of the Process() function.
   for (decltype(len) i = 0; i < len; i++)
   {
      buffer[i] =
         amplitude * 0.5 *
         (sin(A * (i + last).as_double()) + sin(B * (i + last).as_double()));
   }
 
   // generate a fade-in of duration 1/250th of second
   if (last == 0)
   {
      A = std::min<double>(len, (fs / kFadeInOut));
      for (size_t i = 0; i < A; i++)
      {
         buffer[i] *= i / A;
      }
   }
 
   // generate a fade-out of duration 1/250th of second
   if (last >= total - len)
   {
      // we are at the last buffer of 'len' size, so, offset is to
      // backup 'A' samples, from 'len'
      A = std::min<double>(len, (fs / kFadeInOut));
      size_t offset = len - A;
      wxASSERT(offset >= 0);
      for (size_t i = 0; i < A; i++)
      {
         buffer[i + offset] *= (1 - (i / A));
      }
   }
   return true;
}
 
std::shared_ptr<EffectInstance> DtmfBase::MakeInstance() const
{
   // TODO: don't use Effect::mT0 and Effect::mSampleRate, but use an
   // EffectContext (that class is not yet defined)
   return std::make_shared<Instance>(*this, mT0);
}