Pre-warm the model on creation over the size of the receptive field. …

…Removed no longer needed anti-pop code. (#71)

NAM/wavenet.cpp

@@ -269,7 +269,23 @@ wavenet::WaveNet::WaveNet(const double loudness, const std::vector<wavenet::Laye
   }
   this->_head_output.resize(1, 0); // Mono output!
   this->set_params_(params);
-  this->_reset_anti_pop_();
+
+  long receptive_field = 1;
+  for (size_t i = 0; i < this->_layer_arrays.size(); i++)
+    receptive_field += this->_layer_arrays[i].get_receptive_field();
+
+  NAM_SAMPLE sample = 0;
+  NAM_SAMPLE* sample_ptr = &sample;
+
+  std::unordered_map<std::string, double> param_dict = {};
+
+  // pre-warm the model over the size of the receptive field
+  for (long i = 0; i < receptive_field; i++)
+  {
+    this->process(&sample_ptr, &sample_ptr, 1, 1, 1.0, 1.0, param_dict);
+    this->finalize_(1);
+    sample = 0;
+  }
 }
 
 void wavenet::WaveNet::finalize_(const int num_frames)
@@ -325,11 +341,6 @@ void wavenet::WaveNet::_process_core_()
   this->_set_num_frames_(num_frames);
   this->_prepare_for_frames_(num_frames);
 
-  // NOTE: During warm-up, weird things can happen that NaN out the layers.
-  // We could solve this by anti-popping the *input*. But, it's easier to check
-  // the outputs for NaNs and zero them out.
-  // They'll flush out eventually because the model doesn't use any feedback.
-
   // Fill into condition array:
   // Clumsy...
   for (int j = 0; j < num_frames; j++)
@@ -361,13 +372,8 @@ void wavenet::WaveNet::_process_core_()
   for (int s = 0; s < num_frames; s++)
   {
     float out = this->_head_scale * this->_head_arrays[final_head_array](0, s);
-    // This is the NaN check that we could fix with anti-popping the input
-    if (isnan(out))
-      out = 0.0;
     this->_core_dsp_output[s] = out;
   }
-  // Apply anti-pop
-  this->_anti_pop_();
 }
 
 void wavenet::WaveNet::_set_num_frames_(const long num_frames)
@@ -388,27 +394,3 @@ void wavenet::WaveNet::_set_num_frames_(const long num_frames)
   // this->_head.set_num_frames_(num_frames);
   this->_num_frames = num_frames;
 }
-
-void wavenet::WaveNet::_anti_pop_()
-{
-  if (this->_anti_pop_countdown >= this->_anti_pop_ramp)
-    return;
-  const float slope = 1.0f / float(this->_anti_pop_ramp);
-  for (size_t i = 0; i < this->_core_dsp_output.size(); i++)
-  {
-    if (this->_anti_pop_countdown >= this->_anti_pop_ramp)
-      break;
-    const float gain = std::max(slope * float(this->_anti_pop_countdown), 0.0f);
-    this->_core_dsp_output[i] *= gain;
-    this->_anti_pop_countdown++;
-  }
-}
-
-void wavenet::WaveNet::_reset_anti_pop_()
-{
-  // You need the "real" receptive field, not the buffers.
-  long receptive_field = 1;
-  for (size_t i = 0; i < this->_layer_arrays.size(); i++)
-    receptive_field += this->_layer_arrays[i].get_receptive_field();
-  this->_anti_pop_countdown = -receptive_field;
-}

NAM/wavenet.h

@@ -207,14 +207,5 @@ class WaveNet : public DSP
 
   // Ensure that all buffer arrays are the right size for this num_frames
   void _set_num_frames_(const long num_frames);
-
-  // The net starts with random parameters inside; we need to wait for a full
-  // receptive field to pass through before we can count on the output being
-  // ok. This implements a gentle "ramp-up" so that there's no "pop" at the
-  // start.
-  long _anti_pop_countdown;
-  const long _anti_pop_ramp = 4000;
-  void _anti_pop_();
-  void _reset_anti_pop_();
 };
 }; // namespace wavenet