(fix) Waveform scratch crossing loop boundaries

src/engine/controls/ratecontrol.cpp

@@ -34,6 +34,9 @@ RateControl::RateControl(const QString& group,
         UserSettingsPointer pConfig)
         : EngineControl(group, pConfig),
           m_pBpmControl(nullptr),
+          m_wrapAroundCount(0),
+          m_jumpPos(mixxx::audio::FramePos()),
+          m_targetPos(mixxx::audio::FramePos()),
           m_bTempStarted(false),
           m_tempRateRatio(0.0),
           m_dRateTempRampChange(0.0) {
@@ -441,10 +444,10 @@ double RateControl::calculateSpeed(double baserate, double speed, bool paused,
                 // The buffer is playing, so calculate the buffer rate.
 
                 // There are four rate effects we apply: wheel, scratch, jog and temp.
-                // Wheel: a linear additive effect (no spring-back)
+                // Wheel:   a linear additive effect (no spring-back)
                 // Scratch: a rate multiplier
-                // Jog: a linear additive effect whose value is filtered (springs back)
-                // Temp: pitch bend
+                // Jog:     a linear additive effect whose value is filtered (springs back)
+                // Temp:    pitch bend
 
                 // New scratch behavior - overrides playback speed (and old behavior)
                 if (useScratch2Value) {
@@ -459,7 +462,17 @@ double RateControl::calculateSpeed(double baserate, double speed, bool paused,
         }
 
         double currentSample = frameInfo().currentPosition.toEngineSamplePos();
-        m_pScratchController->process(currentSample, rate, iSamplesPerBuffer, baserate);
+        // Let PositionScratchController also know if the play pos wrapped around
+        // (beatloop or track repeat) so it can correctly interpret the sample position delta.
+        m_pScratchController->process(currentSample,
+                rate,
+                iSamplesPerBuffer,
+                baserate,
+                m_wrapAroundCount,
+                m_jumpPos,
+                m_targetPos);
+        // Reset count after use.
+        m_wrapAroundCount = 0;
 
         // If waveform scratch is enabled, override all other controls
         if (m_pScratchController->isEnabled()) {
@@ -603,3 +616,15 @@ bool RateControl::isReverseButtonPressed() {
     }
     return false;
 }
+
+void RateControl::notifyWrapAround(mixxx::audio::FramePos triggerPos,
+        mixxx::audio::FramePos targetPos) {
+    VERIFY_OR_DEBUG_ASSERT(triggerPos.isValid() && targetPos.isValid()) {
+        m_wrapAroundCount = 0;
+        // no need to reset the position, they're not used if count is 0.
+        return;
+    }
+    m_wrapAroundCount++;
+    m_jumpPos = triggerPos;
+    m_targetPos = targetPos;
+}

src/engine/controls/ratecontrol.h

@@ -71,6 +71,11 @@ class RateControl : public EngineControl {
   static void setRateRampSensitivity(int);
   static int getRateRampSensitivity();
   bool isReverseButtonPressed();
+  // ReadAheadManager::getNextSamples() notifies us each time the play position
+  // wrapped around during one buffer process (beatloop or track repeat) so
+  // PositionScratchController can correctly interpret the sample position delta.
+  void notifyWrapAround(mixxx::audio::FramePos triggerPos,
+          mixxx::audio::FramePos targetPos);
 
 public slots:
   void slotRateRangeChanged(double);
@@ -147,6 +152,10 @@ public slots:
   ControlProxy* m_pSyncMode;
   ControlProxy* m_pSlipEnabled;
 
+  int m_wrapAroundCount;
+  mixxx::audio::FramePos m_jumpPos;
+  mixxx::audio::FramePos m_targetPos;
+
   // This is true if we've already started to ramp the rate
   bool m_bTempStarted;
   // Set the Temporary Rate Change Mode

src/engine/enginebuffer.cpp

@@ -843,9 +843,9 @@ void EngineBuffer::processTrackLocked(
     m_trackSampleRateOld = mixxx::audio::SampleRate::fromDouble(m_pTrackSampleRate->get());
     m_trackEndPositionOld = getTrackEndPosition();
 
-    double baserate = 0.0;
+    double baseSampleRate = 0.0;
     if (sampleRate.isValid()) {
-        baserate = m_trackSampleRateOld / sampleRate;
+        baseSampleRate = m_trackSampleRateOld / sampleRate;
     }
 
     // Sync requests can affect rate, so process those first.
@@ -875,7 +875,7 @@ void EngineBuffer::processTrackLocked(
     // pass for every 1 real second). Depending on whether
     // keylock is enabled, this is applied to either the rate or the tempo.
     double speed = m_pRateControl->calculateSpeed(
-            baserate,
+            baseSampleRate,
             tempoRatio,
             paused,
             iBufferSize,
@@ -980,10 +980,10 @@ void EngineBuffer::processTrackLocked(
     // otherwise tempo and pitch are processed individual
 
     double rate = 0;
-    // If the baserate, speed, or pitch has changed, we need to update the
+    // If the base samplerate, speed, or pitch has changed, we need to update the
     // scaler. Also, if we have changed scalers then we need to update the
     // scaler.
-    if (baserate != m_baserate_old || speed != m_speed_old ||
+    if (baseSampleRate != m_baserate_old || speed != m_speed_old ||
             pitchRatio != m_pitch_old || tempoRatio != m_tempo_ratio_old ||
             m_bScalerChanged) {
         // The rate returned by the scale object can be different from the
@@ -1005,7 +1005,7 @@ void EngineBuffer::processTrackLocked(
             m_pScale->clear();
         }
 
-        m_baserate_old = baserate;
+        m_baserate_old = baseSampleRate;
         m_speed_old = speed;
         m_pitch_old = pitchRatio;
         m_tempo_ratio_old = tempoRatio;
@@ -1016,16 +1016,16 @@ void EngineBuffer::processTrackLocked(
         // main samplerate), the deck speed, the pitch shift, and whether
         // the deck speed should affect the pitch.
 
-        m_pScale->setScaleParameters(baserate,
-                                     &speed,
-                                     &pitchRatio);
+        m_pScale->setScaleParameters(baseSampleRate,
+                &speed,
+                &pitchRatio);
 
         // The way we treat rate inside of EngineBuffer is actually a
         // description of "sample consumption rate" or percentage of samples
         // consumed relative to playing back the track at its native sample
         // rate and normal speed. pitch_adjust does not change the playback
         // rate.
-        rate = baserate * speed;
+        rate = baseSampleRate * speed;
 
         // Scaler is up to date now.
         m_bScalerChanged = false;