better rubberband loop fading

Author: benkuper

Source/Node/nodes/sampler/SamplerNode.cpp

@@ -56,7 +56,7 @@ SamplerNode::SamplerNode(var params) :
     autoKeyLiveMode = controlsCC.addBoolParameter("Auto Key", "If checked, hitting an unrecorded note will play it repitched from the closest found", false);
     autoKeyFadeTimeMS = controlsCC.addIntParameter("Auto Key Fade", "Fade for anticlick when repitching auto keys, in milliseconds", 50);
 
-    autoKeyLoopFade = controlsCC.addBoolParameter("Auto Key Loop Fade", "If checked, generated auto-key samples are shortened and overlap-blended so the loop start and end match more cleanly.", false);
+    autoKeyLoopFade = controlsCC.addBoolParameter("Auto Key Loop Fade", "If checked, generated auto-key samples are shortened and overlap-blended so the loop start and end match more cleanly.", false);
     autoKeyMode = controlsCC.addEnumParameter("Auto Key Algorithm", "Algorithm used to pitch-shift when computing auto keys.\nResample: clean, no wobble, slight formant shift.\nRubberBand: phase vocoder, preserves formants, may wobble on tonal sounds.");
     autoKeyMode->addOption("RubberBand", RUBBERBAND)->addOption("Resample", RESAMPLE);
 
@@ -195,28 +195,28 @@ void SamplerNode::resetAllNotes()
     }
 }
 
-void SamplerNode::computeAutoKeys()
-{
-    for (int i = 0; i < samplerNotes.size(); i++)
-    {
-        NoteState ns = samplerNotes[i]->state->getValueDataAsEnum<NoteState>();
-        if (ns == PROCESSING || samplerNotes[i]->isProxyNote()) clearNote(i);
-    }
-
-    int startKey = startAutoKey->intValue();
-    int endKey = endAutoKey->intValue();
-    
-    // Grab UI settings to pass to threads
-    bool formants = rbPreserveFormants->boolValue();
-    int transients = rbTransients->getValueDataAsEnum<int>();
-    int pitchMode = rbPitchMode->getValueDataAsEnum<int>();
-    int windowSize = rbWindowSize->getValueDataAsEnum<int>();
-    bool shouldLoopFade = autoKeyLoopFade->boolValue();
-
-    for (int i = startKey; i <= endKey; i++)
-    {
-        SamplerNote* n = samplerNotes[i];
-        if (n == nullptr) return;
+void SamplerNode::computeAutoKeys()
+{
+    for (int i = 0; i < samplerNotes.size(); i++)
+    {
+        NoteState ns = samplerNotes[i]->state->getValueDataAsEnum<NoteState>();
+        if (ns == PROCESSING || samplerNotes[i]->isProxyNote()) clearNote(i);
+    }
+
+    int startKey = startAutoKey->intValue();
+    int endKey = endAutoKey->intValue();
+    
+    // Grab UI settings to pass to threads
+    bool formants = rbPreserveFormants->boolValue();
+    int transients = rbTransients->getValueDataAsEnum<int>();
+    int pitchMode = rbPitchMode->getValueDataAsEnum<int>();
+    int windowSize = rbWindowSize->getValueDataAsEnum<int>();
+    bool shouldLoopFade = autoKeyLoopFade->boolValue();
+
+    for (int i = startKey; i <= endKey; i++)
+    {
+        SamplerNote* n = samplerNotes[i];
+        if (n == nullptr) return;
         NoteState ns = n->state->getValueDataAsEnum<NoteState>();
         if (ns != EMPTY) continue;
 
@@ -235,17 +235,17 @@ void SamplerNode::computeAutoKeys()
                 {
                     closestNote = highI;
                     break;
-                }
-            }
-        }
-
-        if (closestNote != -1)
-        {
-            double shift = MidiMessage::getMidiNoteInHertz(i) / MidiMessage::getMidiNoteInHertz(closestNote);
-            n->computeAutoKey(samplerNotes[closestNote], shift, getFadeNumSamples(autoKeyFadeTimeMS->intValue()), autoKeyMode->getValueDataAsEnum<AutoKeyAlgorithm>(), formants, transients, pitchMode, windowSize, shouldLoopFade);
-        }
-    }
-}
+                }
+            }
+        }
+
+        if (closestNote != -1)
+        {
+            double shift = MidiMessage::getMidiNoteInHertz(i) / MidiMessage::getMidiNoteInHertz(closestNote);
+            n->computeAutoKey(samplerNotes[closestNote], shift, getFadeNumSamples(autoKeyFadeTimeMS->intValue()), autoKeyMode->getValueDataAsEnum<AutoKeyAlgorithm>(), formants, transients, pitchMode, windowSize, shouldLoopFade);
+        }
+    }
+}
 
 
 void SamplerNode::updateBuffers()
@@ -1050,11 +1050,11 @@ SamplerNode::SamplerNote::~SamplerNote()
     stopThread(1000);
 }
 
-void SamplerNode::SamplerNote::setAutoKey(SamplerNote* remoteNote, double shift)
-{
-    autoKeyFromNote = remoteNote;
-    if (autoKeyFromNote == nullptr)
-    {
+void SamplerNode::SamplerNote::setAutoKey(SamplerNote* remoteNote, double shift)
+{
+    autoKeyFromNote = remoteNote;
+    if (autoKeyFromNote == nullptr)
+    {
         rtPitchedBuffer.clear();
         return;
     }
@@ -1073,28 +1073,28 @@ void SamplerNode::SamplerNote::setAutoKey(SamplerNote* remoteNote, double shift)
         ));
     }
 
-    pitcher->reset();
-    pitcher->setMaxProcessSize(Transport::getInstance()->blockSize);
-    pitcher->setPitchScale(shift);
-    rtPitchReadSample = 0;
-    rtPitchedBuffer.setSize(autoKeyFromNote->buffer.getNumChannels(), Transport::getInstance()->blockSize);
-}
-
-void SamplerNode::SamplerNote::computeAutoKey(SamplerNote* remoteNote, double shift, int fadeSamples, int algorithm, bool formants, int transients, int pitchMode, int windowSize, bool shouldLoopFade)
-{
-    shifting = shift;
-    fadeNumSamples = fadeSamples;
-    autoKeyAlgorithm = algorithm;
-    autoKeyFromNote = remoteNote;
-    
-    optFormants = formants;
-    optTransients = transients;
-    optPitchMode = pitchMode;
-    optWindow = windowSize;
-    loopFadeEnabled = shouldLoopFade;
-    
-    startThread();
-}
+    pitcher->reset();
+    pitcher->setMaxProcessSize(Transport::getInstance()->blockSize);
+    pitcher->setPitchScale(shift);
+    rtPitchReadSample = 0;
+    rtPitchedBuffer.setSize(autoKeyFromNote->buffer.getNumChannels(), Transport::getInstance()->blockSize);
+}
+
+void SamplerNode::SamplerNote::computeAutoKey(SamplerNote* remoteNote, double shift, int fadeSamples, int algorithm, bool formants, int transients, int pitchMode, int windowSize, bool shouldLoopFade)
+{
+    shifting = shift;
+    fadeNumSamples = fadeSamples;
+    autoKeyAlgorithm = algorithm;
+    autoKeyFromNote = remoteNote;
+    
+    optFormants = formants;
+    optTransients = transients;
+    optPitchMode = pitchMode;
+    optWindow = windowSize;
+    loopFadeEnabled = shouldLoopFade;
+    
+    startThread();
+}
 
 void SamplerNode::SamplerNote::run()
 {
@@ -1126,6 +1126,8 @@ void SamplerNode::SamplerNote::run()
 
     AudioBuffer<float> pitchedFull(numChannels, numSamples);
     pitchedFull.clear();
+    AudioBuffer<float> loopContinuation(numChannels, 0);
+    int renderedNumSamples = numSamples;
 
     if (autoKeyAlgorithm == SamplerNode::RESAMPLE)
     {
@@ -1170,30 +1172,24 @@ void SamplerNode::SamplerNote::run()
         rubberBand.setPitchScale(safeShift);
         rubberBand.setTimeRatio(1.0);
 
-        // The render can either settle into silence or include post-roll from
-        // the start so the generated note can be overlap-looped afterward.
-        int minAntiClick = (int)(Transport::getInstance()->sampleRate * 0.005);
-        const int loopFadeSamples = jmin(jmax(0, numSamples - 1), jmax(fadeNumSamples, minAntiClick));
-        const int paddedInputSamples = numSamples + loopFadeSamples;
-
-        AudioBuffer<float> paddedSource(numChannels, paddedInputSamples);
-        paddedSource.clear();
-        for (int ch = 0; ch < numChannels; ++ch)
-        {
-            paddedSource.copyFrom(ch, 0, sourceCopy, ch, 0, numSamples);
-
-            if (loopFadeSamples > 0)
-            {
-                if (loopFadeEnabled)
-                {
-                    paddedSource.copyFrom(ch, numSamples, sourceCopy, ch, 0, loopFadeSamples);
-                }
-                else
-                {
-                    paddedSource.applyGainRamp(ch, numSamples - loopFadeSamples, loopFadeSamples, 1.0f, 0.0f);
-                }
-            }
-        }
+        // In loop-fade mode we append a short post-roll from the start so the
+        // rendered note contains the material needed to close the loop seam.
+        const int loopFadeSamples = loopFadeEnabled
+            ? jmin(jmax(0, numSamples - 1), fadeNumSamples)
+            : 0;
+        const int paddedInputSamples = numSamples + loopFadeSamples;
+
+        AudioBuffer<float> paddedSource(numChannels, paddedInputSamples);
+        paddedSource.clear();
+        for (int ch = 0; ch < numChannels; ++ch)
+        {
+            paddedSource.copyFrom(ch, 0, sourceCopy, ch, 0, numSamples);
+
+            if (loopFadeEnabled && loopFadeSamples > 0)
+            {
+                paddedSource.copyFrom(ch, numSamples, sourceCopy, ch, 0, loopFadeSamples);
+            }
+        }
 
         rubberBand.setExpectedInputDuration((size_t)paddedInputSamples);
 
@@ -1235,45 +1231,71 @@ void SamplerNode::SamplerNote::run()
             }
         }
 
-        // 6. Copy the requested note body. Loop overlap is applied afterward so
-        // both algorithms share the same seam treatment.
-        for (int ch = 0; ch < numChannels; ++ch)
-        {
-            const int availableMainSamples = jmin(numSamples, collected);
-            if (availableMainSamples > 0)
-                pitchedFull.copyFrom(ch, 0, fullOutput, ch, 0, availableMainSamples);
-        }
-    }
-
-    if (loopFadeEnabled)
-    {
-        const int crossfadeSamples = jmin(jmax(0, pitchedFull.getNumSamples() - 1), fadeNumSamples);
-        if (crossfadeSamples > 0)
-        {
-            const int loopedNumSamples = pitchedFull.getNumSamples() - crossfadeSamples;
-            AudioBuffer<float> loopedBuffer(numChannels, loopedNumSamples);
-
-            for (int ch = 0; ch < numChannels; ++ch)
-            {
-                loopedBuffer.copyFrom(ch, 0, pitchedFull, ch, 0, loopedNumSamples);
-
-                for (int i = 0; i < crossfadeSamples; ++i)
-                {
-                    const float alpha = crossfadeSamples == 1 ? 1.0f : (float)i / (float)(crossfadeSamples - 1);
-                    const float tailGain = std::cos(alpha * MathConstants<float>::halfPi);
-                    const float headGain = std::sin(alpha * MathConstants<float>::halfPi);
-                    const float tailSample = pitchedFull.getSample(ch, loopedNumSamples + i);
-                    const float headSample = pitchedFull.getSample(ch, i);
-                    loopedBuffer.setSample(ch, i, tailSample * tailGain + headSample * headGain);
-                }
-            }
-
-            pitchedFull.makeCopyOf(loopedBuffer);
-        }
-    }
-
-    // Replace the buffer
-    buffer.makeCopyOf(pitchedFull);
+        // 6. Copy the requested note body. Loop overlap is applied afterward so
+        // both algorithms share the same seam treatment.
+        for (int ch = 0; ch < numChannels; ++ch)
+        {
+            const int availableMainSamples = jmin(numSamples, collected);
+            if (availableMainSamples > 0)
+                pitchedFull.copyFrom(ch, 0, fullOutput, ch, 0, availableMainSamples);
+        }
+
+        renderedNumSamples = jmax(0, jmin(numSamples, collected));
+
+        if (loopFadeEnabled && loopFadeSamples > 0)
+        {
+            const int availableContinuation = jmin(loopFadeSamples, jmax(0, collected - renderedNumSamples));
+            if (availableContinuation > 0)
+            {
+                loopContinuation.setSize(numChannels, availableContinuation);
+                for (int ch = 0; ch < numChannels; ++ch)
+                    loopContinuation.copyFrom(ch, 0, fullOutput, ch, renderedNumSamples, availableContinuation);
+            }
+        }
+    }
+
+    if (loopFadeEnabled)
+    {
+        const int crossfadeSamples = jmin(jmax(0, renderedNumSamples / 2), fadeNumSamples);
+        if (crossfadeSamples > 0)
+        {
+            const int loopedNumSamples = renderedNumSamples - crossfadeSamples;
+            AudioBuffer<float> loopedBuffer(numChannels, loopedNumSamples);
+            loopedBuffer.clear();
+            const int bodySamples = jmax(0, loopedNumSamples - crossfadeSamples);
+
+            for (int ch = 0; ch < numChannels; ++ch)
+            {
+                if (bodySamples > 0)
+                    loopedBuffer.copyFrom(ch, 0, pitchedFull, ch, crossfadeSamples, bodySamples);
+
+                for (int i = 0; i < crossfadeSamples; ++i)
+                {
+                    const float alpha = crossfadeSamples == 1 ? 1.0f : (float)i / (float)(crossfadeSamples - 1);
+                    const float tailGain = std::cos(alpha * MathConstants<float>::halfPi);
+                    const float headGain = std::sin(alpha * MathConstants<float>::halfPi);
+                    const float tailSample = loopContinuation.getNumSamples() > i
+                        ? loopContinuation.getSample(ch, i)
+                        : pitchedFull.getSample(ch, i);
+                    const float headSample = pitchedFull.getSample(ch, loopedNumSamples + i);
+                    loopedBuffer.setSample(ch, bodySamples + i, headSample * tailGain + tailSample * headGain);
+                }
+            }
+
+            pitchedFull.makeCopyOf(loopedBuffer);
+            renderedNumSamples = loopedNumSamples;
+        }
+    }
+    else if (renderedNumSamples > 0 && renderedNumSamples < pitchedFull.getNumSamples())
+    {
+        AudioBuffer<float> trimmedBuffer(numChannels, renderedNumSamples);
+        trimmedBuffer.makeCopyOf(pitchedFull, true);
+        trimmedBuffer.setSize(numChannels, renderedNumSamples, true, false, true);
+        pitchedFull.makeCopyOf(trimmedBuffer);
+    }
+
+    // Replace the buffer
+    buffer.makeCopyOf(pitchedFull);
 
     autoKeyFromNote = nullptr;
     state->setValueWithData(NoteState::FILLED);