Fix bug reporting latency (#489)

Author: sdatkinson

NeuralAmpModeler/NeuralAmpModeler.cpp

@@ -366,6 +366,7 @@ void NeuralAmpModeler::OnReset()
   // If there is a model or IR loaded, they need to be checked for resampling.
   _ResetModelAndIR(sampleRate, GetBlockSize());
   mToneStack->Reset(sampleRate, maxBlockSize);
+  _UpdateLatency();
 }
 
 void NeuralAmpModeler::OnIdle()
@@ -533,7 +534,7 @@ void NeuralAmpModeler::_ApplyDSPStaging()
     mModel = nullptr;
     mNAMPath.Set("");
     mShouldRemoveModel = false;
-    SetLatency(0);
+    _UpdateLatency();
   }
   if (mShouldRemoveIR)
   {
@@ -548,7 +549,7 @@ void NeuralAmpModeler::_ApplyDSPStaging()
     mModel = std::move(mStagedModel);
     mStagedModel = nullptr;
     mNewModelLoadedInDSP = true;
-    SetLatency(mModel->GetLatency());
+    _UpdateLatency();
   }
   if (mStagedIR != nullptr)
   {
@@ -881,6 +882,17 @@ int NeuralAmpModeler::_UnserializeStateLegacy_0_7_9(const IByteChunk& chunk, int
   return pos;
 }
 
+void NeuralAmpModeler::_UpdateLatency()
+{
+  int latency = 0;
+  if (mModel)
+  {
+    latency += mModel->GetLatency();
+  }
+  // Other things that add latency here...
+  SetLatency(latency);
+}
+
 void NeuralAmpModeler::_UpdateMeters(sample** inputPointer, sample** outputPointer, const size_t nFrames,
                                      const size_t nChansIn, const size_t nChansOut)
 {

NeuralAmpModeler/NeuralAmpModeler.h

@@ -126,7 +126,7 @@ class ResamplingNAM : public nam::DSP
       // We can afford to be careful
       throw std::runtime_error("More frames were provided than the max expected!");
 
-    if (GetExpectedSampleRate() == GetEncapsulatedSampleRate())
+    if (!NeedToResample())
     {
       mEncapsulated->process(input, output, num_frames);
       mEncapsulated->finalize_(num_frames);
@@ -156,7 +156,7 @@ class ResamplingNAM : public nam::DSP
     mFinalized = true;
   };
 
-  int GetLatency() const { return mResampler.GetLatency(); };
+  int GetLatency() const { return NeedToResample() ? mResampler.GetLatency() : 0; };
 
   void Reset(const double sampleRate, const int maxBlockSize)
   {
@@ -182,6 +182,7 @@ class ResamplingNAM : public nam::DSP
   double GetEncapsulatedSampleRate() const { return GetNAMSampleRate(mEncapsulated); };
 
 private:
+  bool NeedToResample() const { return GetExpectedSampleRate() != GetEncapsulatedSampleRate(); };
   // The encapsulated NAM
   std::unique_ptr<nam::DSP> mEncapsulated;
   // The processing for NAM is a little weird--there's a call to .finalize_() that's expected.
@@ -271,6 +272,9 @@ class NeuralAmpModeler final : public iplug::Plugin
   int _UnserializeStateLegacy_0_7_9(const iplug::IByteChunk& chunk, int startPos);
   // And other legacy unsrializations if/as needed...
 
+  // Make sure that the latency is reported correctly.
+  void _UpdateLatency();
+
   // Update level meters
   // Called within ProcessBlock().
   // Assume _ProcessInput() and _ProcessOutput() were run immediately before.