Move pre-warm to DSP and call it in get_dsp() (#90)

NAM/convnet.cpp

@@ -109,8 +109,13 @@ convnet::ConvNet::ConvNet(const int channels, const std::vector<int>& dilations,
   this->_head = _Head(channels, it);
   if (it != params.end())
     throw std::runtime_error("Didn't touch all the params when initializing ConvNet");
+
+  _prewarm_samples = 1;
+  for (size_t i = 0; i < dilations.size(); i++)
+    _prewarm_samples += dilations[i];
 }
 
+
 void convnet::ConvNet::process(NAM_SAMPLE* input, NAM_SAMPLE* output, const int num_frames)
 
 {

NAM/dsp.cpp

@@ -21,6 +21,23 @@ DSP::DSP(const double expected_sample_rate)
 {
 }
 
+void DSP::prewarm()
+{
+  if (_prewarm_samples == 0)
+    return;
+
+  NAM_SAMPLE sample = 0;
+  NAM_SAMPLE* sample_ptr = &sample;
+
+  // pre-warm the model for a model-specific number of samples
+  for (long i = 0; i < _prewarm_samples; i++)
+  {
+    this->process(sample_ptr, sample_ptr, 1);
+    this->finalize_(1);
+    sample = 0;
+  }
+}
+
 void DSP::process(NAM_SAMPLE* input, NAM_SAMPLE* output, const int num_frames)
 {
   // Default implementation is the null operation

NAM/dsp.h

@@ -50,6 +50,9 @@ class DSP
   // We may choose to have the models figure out for themselves how loud they are in here in the future.
   DSP(const double expected_sample_rate);
   virtual ~DSP() = default;
+  // prewarm() does any required intial work required to "settle" model initial conditions
+  // it can be somewhat expensive, so should not be called during realtime audio processing
+  virtual void prewarm();
   // process() does all of the processing requried to take `input` array and
   // fill in the required values on `output`.
   // To do this:
@@ -87,6 +90,7 @@ class DSP
   std::unordered_map<std::string, double> _params;
   // If the params have changed since the last buffer was processed:
   bool _stale_params = true;
+  int _prewarm_samples = 0;
 
   // Methods
 

NAM/get_dsp.cpp

@@ -211,5 +211,9 @@ std::unique_ptr<DSP> get_dsp(dspData& conf)
   {
     out->SetLoudness(loudness);
   }
+
+  // "pre-warm" the model to settle initial conditions
+  out->prewarm();
+
   return out;
 }

NAM/wavenet.cpp

@@ -263,20 +263,9 @@ wavenet::WaveNet::WaveNet(const std::vector<wavenet::LayerArrayParams>& layer_ar
   this->_head_output.resize(1, 0); // Mono output!
   this->set_params_(params);
 
-  long receptive_field = 1;
+  _prewarm_samples = 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;
-
-  // 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);
-    this->finalize_(1);
-    sample = 0;
-  }
+    _prewarm_samples += this->_layer_arrays[i].get_receptive_field();
 }
 
 void wavenet::WaveNet::finalize_(const int num_frames)

NAM/wavenet.h

@@ -199,7 +199,6 @@ class WaveNet : public DSP
   // Get the info from the parametric config
   void _init_parametric_(nlohmann::json& parametric);
   void _prepare_for_frames_(const long num_frames);
-  // Reminder: From ._input_post_gain to ._core_dsp_output
   void process(NAM_SAMPLE* input, NAM_SAMPLE* output, const int num_frames) override;
 
   // Ensure that all buffer arrays are the right size for this num_frames