Reworked beat_active control:

src/engine/controls/bpmcontrol.cpp

@@ -570,7 +570,7 @@ bool BpmControl::getBeatContext(const mixxx::BeatsPointer& pBeats,
 
     double dPrevBeat;
     double dNextBeat;
-    if (!pBeats->findPrevNextBeats(dPosition, &dPrevBeat, &dNextBeat)) {
+    if (!pBeats->findPrevNextBeats(dPosition, &dPrevBeat, &dNextBeat, false)) {
         return false;
     }
 
@@ -605,14 +605,6 @@ bool BpmControl::getBeatContextNoLookup(
     if (dpBeatPercentage != nullptr) {
         *dpBeatPercentage = dBeatLength == 0.0 ? 0.0 :
                 (dPosition - dPrevBeat) / dBeatLength;
-        // Because findNext and findPrev have an epsilon built in, sometimes
-        // the beat percentage is out of range.  Fix it.
-        if (*dpBeatPercentage < 0) {
-            ++*dpBeatPercentage;
-        }
-        if (*dpBeatPercentage > 1) {
-            --*dpBeatPercentage;
-        }
     }
 
     return true;

src/engine/controls/clockcontrol.cpp

@@ -7,16 +7,31 @@
 #include "preferences/usersettings.h"
 #include "track/track.h"
 
+namespace {
+constexpr double kBlinkInterval = 0.20; // LED is on 20% of the beat period
+constexpr double kStandStillTolerance =
+        0.005; // (seconds) Minimum change, to he last evaluated position
+constexpr double kSignificiantRateThreshold =
+        0.1; // If rate is significiant, update indicator also inside standstill tolerance
+} // namespace
+
 ClockControl::ClockControl(const QString& group, UserSettingsPointer pConfig)
         : EngineControl(group, pConfig) {
     m_pCOBeatActive = new ControlObject(ConfigKey(group, "beat_active"));
-    m_pCOBeatActive->set(0.0);
-    m_pCOSampleRate = new ControlProxy("[Master]","samplerate");
+    m_pCOBeatActive->setReadOnly();
+    m_pCOBeatActive->forceSet(0.0);
+    m_lastEvaluatedSample = 0;
+    m_PrevBeatSamples = 0;
+    m_InternalState = StateMachine::outsideIndicationArea;
+    m_NextBeatSamples = 0;
+    m_blinkIntervalSamples = 0;
+    m_pLoopEnabled = new ControlProxy(group, "loop_enabled", this);
+    m_pLoopStartPosition = new ControlProxy(group, "loop_start_position", this);
+    m_pLoopEndPosition = new ControlProxy(group, "loop_end_position", this);
 }
 
 ClockControl::~ClockControl() {
     delete m_pCOBeatActive;
-    delete m_pCOSampleRate;
 }
 
 // called from an engine worker thread
@@ -30,27 +45,154 @@ void ClockControl::trackLoaded(TrackPointer pNewTrack) {
 
 void ClockControl::trackBeatsUpdated(mixxx::BeatsPointer pBeats) {
     // Clear on-beat control
-    m_pCOBeatActive->set(0.0);
+    m_pCOBeatActive->forceSet(0.0);
     m_pBeats = pBeats;
 }
 
 void ClockControl::process(const double dRate,
-                           const double currentSample,
-                           const int iBuffersize) {
+        const double currentSample,
+        const int iBuffersize) {
+    Q_UNUSED(dRate);
+    Q_UNUSED(currentSample);
     Q_UNUSED(iBuffersize);
-    double samplerate = m_pCOSampleRate->get();
+}
 
-    // TODO(XXX) should this be customizable, or latency dependent?
-    const double blinkSeconds = 0.100;
+void ClockControl::updateIndicators(const double dRate,
+        const double currentSample,
+        const double sampleRate) {
+    /* This method sets the control beat_active is set to the following values:
+    *  0.0 --> No beat indication (ouside 20% area or play direction changed while indication was on)
+    *  1.0 --> Forward playing, set at the beat and set back to 0.0 at 20% of beat distance
+    *  2.0 --> Reverse playing, set at the beat and set back to 0.0 at -20% of beat distance
+    */
 
-    // Multiply by two to get samples from frames. Interval is scaled linearly
-    // by the rate.
-    const double blinkIntervalSamples = 2.0 * samplerate * (1.0 * dRate) * blinkSeconds;
+    // No position change since last indicator update (e.g. deck stopped) -> No indicator update needed
+    // The kSignificiantRateThreshold condition ensures an immidiate indicator update, when the play/cue button is pressed
+    if ((currentSample <= (m_lastEvaluatedSample + kStandStillTolerance * sampleRate)) &&
+            (currentSample >= (m_lastEvaluatedSample - kStandStillTolerance * sampleRate)) &&
+            (fabs(dRate) <= kSignificiantRateThreshold)) {
+        return;
+    }
+
+    // Position change more significiantly, but rate is zero. Occurs when pressing a cue point
+    // The m_InternalState needs to be taken into account here to prevent uneccessary events (state 0 -> state 0)
+    if ((dRate == 0.0) && (m_InternalState != StateMachine::outsideIndicationArea)) {
+        m_InternalState = StateMachine::outsideIndicationArea;
+        m_pCOBeatActive->forceSet(0.0);
+    }
+
+    double prevIndicatorSamples;
+    double nextIndicatorSamples;
 
     const mixxx::BeatsPointer pBeats = m_pBeats;
     if (pBeats) {
-        double closestBeat = pBeats->findClosestBeat(currentSample);
-        double distanceToClosestBeat = fabs(currentSample - closestBeat);
-        m_pCOBeatActive->set(distanceToClosestBeat < blinkIntervalSamples / 2.0);
+        if ((currentSample >= m_NextBeatSamples) ||
+                (currentSample <= m_PrevBeatSamples)) {
+            pBeats->findPrevNextBeats(currentSample,
+                    &m_PrevBeatSamples,
+                    &m_NextBeatSamples,
+                    false); // Precise compare without tolerance needed
+        }
+    } else {
+        m_PrevBeatSamples = -1;
+        m_NextBeatSamples = -1;
+    }
+
+    // Loops need special handling
+    if (m_pLoopEnabled->toBool()) {
+        const double loop_start_position = m_pLoopStartPosition->get();
+        const double loop_end_position = m_pLoopEndPosition->get();
+
+        if ((m_PrevBeatSamples < loop_start_position) && (m_NextBeatSamples >= loop_end_position)) {
+            // No beat inside loop -> show beat indication at loop_start_position
+            prevIndicatorSamples = loop_start_position;
+            nextIndicatorSamples = loop_end_position;
+        } else {
+            prevIndicatorSamples = m_PrevBeatSamples;
+            nextIndicatorSamples = m_NextBeatSamples;
+        }
+
+        if ((m_PrevBeatSamples != -1) && (m_NextBeatSamples != -1)) {
+            // Don't overwrite interval at begin/end of track
+            if ((loop_end_position - loop_start_position) <
+                    (m_NextBeatSamples - m_PrevBeatSamples)) {
+                // Loops smaller than beat distance -> Set m_blinkIntervalSamples based on loop period
+                m_blinkIntervalSamples =
+                        (loop_end_position - loop_start_position) *
+                        kBlinkInterval;
+            } else {
+                m_blinkIntervalSamples =
+                        (nextIndicatorSamples - prevIndicatorSamples) *
+                        kBlinkInterval;
+            }
+        }
+    } else {
+        prevIndicatorSamples = m_PrevBeatSamples;
+        nextIndicatorSamples = m_NextBeatSamples;
+
+        if ((prevIndicatorSamples != -1) && (nextIndicatorSamples != -1)) {
+            // Don't overwrite interval at begin/end of track
+            m_blinkIntervalSamples =
+                    (nextIndicatorSamples - prevIndicatorSamples) *
+                    kBlinkInterval;
+        }
+    }
+
+    // The m_InternalState needs to be taken into account, to show a reliable beat indication for loops
+    if (dRate > 0.0) {
+        if (m_lastPlayDirection == true) {
+            if ((currentSample > prevIndicatorSamples) &&
+                    (currentSample <
+                            prevIndicatorSamples + m_blinkIntervalSamples) &&
+                    (m_InternalState != StateMachine::afterBeatActive) &&
+                    (m_InternalState != StateMachine::afterBeatDirectionChanged)) {
+                m_InternalState = StateMachine::afterBeatActive;
+                m_pCOBeatActive->forceSet(1.0);
+            } else if ((currentSample > prevIndicatorSamples +
+                                       m_blinkIntervalSamples) &&
+                    ((m_InternalState == StateMachine::afterBeatActive) ||
+                            (m_InternalState == StateMachine::afterBeatDirectionChanged))) {
+                m_InternalState = StateMachine::outsideIndicationArea;
+                m_pCOBeatActive->forceSet(0.0);
+            }
+        } else {
+            // Play direction changed while beat indicator was on and forward playing
+            if ((currentSample < nextIndicatorSamples) &&
+                    (currentSample >=
+                            nextIndicatorSamples - m_blinkIntervalSamples) &&
+                    (m_InternalState != StateMachine::beforeBeatDirectionChanged)) {
+                m_InternalState = StateMachine::beforeBeatDirectionChanged;
+                m_pCOBeatActive->forceSet(0.0);
+            }
+        }
+        m_lastPlayDirection = true; // Forward
+    } else if (dRate < 0.0) {
+        if (m_lastPlayDirection == false) {
+            if ((currentSample < nextIndicatorSamples) &&
+                    (currentSample >
+                            nextIndicatorSamples - m_blinkIntervalSamples) &&
+                    (m_InternalState != StateMachine::beforeBeatActive) &&
+                    (m_InternalState != StateMachine::beforeBeatDirectionChanged)) {
+                m_InternalState = StateMachine::beforeBeatActive;
+                m_pCOBeatActive->forceSet(2.0);
+            } else if ((currentSample < nextIndicatorSamples -
+                                       m_blinkIntervalSamples) &&
+                    ((m_InternalState == StateMachine::beforeBeatActive) ||
+                            (m_InternalState == StateMachine::beforeBeatDirectionChanged))) {
+                m_InternalState = StateMachine::outsideIndicationArea;
+                m_pCOBeatActive->forceSet(0.0);
+            }
+        } else {
+            // Play direction changed while beat indicator was on and reverse playing
+            if ((currentSample > prevIndicatorSamples) &&
+                    (currentSample <=
+                            prevIndicatorSamples + m_blinkIntervalSamples) &&
+                    (m_InternalState != StateMachine::afterBeatDirectionChanged)) {
+                m_InternalState = StateMachine::afterBeatDirectionChanged;
+                m_pCOBeatActive->forceSet(0.0);
+            }
+        }
+        m_lastPlayDirection = false; // Reverse
     }
+    m_lastEvaluatedSample = currentSample;
 }

src/engine/controls/clockcontrol.h

@@ -19,12 +19,44 @@ class ClockControl: public EngineControl {
     void process(const double dRate, const double currentSample,
             const int iBufferSize) override;
 
+    void updateIndicators(const double dRate,
+            const double currentSample,
+            const double sampleRate);
+
     void trackLoaded(TrackPointer pNewTrack) override;
     void trackBeatsUpdated(mixxx::BeatsPointer pBeats) override;
 
   private:
     ControlObject* m_pCOBeatActive;
-    ControlProxy* m_pCOSampleRate;
+
+    // ControlObjects that come from LoopingControl
+    ControlProxy* m_pLoopEnabled;
+    ControlProxy* m_pLoopStartPosition;
+    ControlProxy* m_pLoopEndPosition;
+
+    double m_lastEvaluatedSample;
+
+    enum class StateMachine : int {
+        afterBeatDirectionChanged =
+                2, /// Direction changed to reverse playing while forward playing indication was on
+        afterBeatActive =
+                1, /// Forward playing, set at the beat and set back to 0.0 at 20% of beat distance
+        outsideIndicationArea =
+                0, /// Outside -20% ... +20% of the beat distance
+        beforeBeatActive =
+                -1, /// Reverse playing, set at the beat and set back to 0.0 at -20% of beat distance
+        beforeBeatDirectionChanged =
+                -2 /// Direction changed to forward playing while reverse playing indication was on
+    };
+
+    StateMachine m_InternalState;
+
+    double m_PrevBeatSamples;
+    double m_NextBeatSamples;
+    double m_blinkIntervalSamples;
+
+    // True is forward direction, False is reverse
+    bool m_lastPlayDirection;
 
     // m_pBeats is written from an engine worker thread
     mixxx::BeatsPointer m_pBeats;

src/engine/controls/loopingcontrol.cpp

@@ -1194,7 +1194,7 @@ void LoopingControl::slotBeatLoop(double beats, bool keepStartPoint, bool enable
         // The closest beat might be ahead of play position and will cause a catching loop.
         double prevBeat;
         double nextBeat;
-        pBeats->findPrevNextBeats(currentSample, &prevBeat, &nextBeat);
+        pBeats->findPrevNextBeats(currentSample, &prevBeat, &nextBeat, true);
 
         if (m_pQuantizeEnabled->toBool() && prevBeat != -1) {
             double beatLength = nextBeat - prevBeat;

src/engine/controls/quantizecontrol.cpp

@@ -80,7 +80,7 @@ void QuantizeControl::lookupBeatPositions(double dCurrentSample) {
     mixxx::BeatsPointer pBeats = m_pBeats;
     if (pBeats) {
         double prevBeat, nextBeat;
-        pBeats->findPrevNextBeats(dCurrentSample, &prevBeat, &nextBeat);
+        pBeats->findPrevNextBeats(dCurrentSample, &prevBeat, &nextBeat, true);
         m_pCOPrevBeat->set(prevBeat);
         m_pCONextBeat->set(nextBeat);
     }

src/engine/enginebuffer.cpp

@@ -1356,6 +1356,12 @@ void EngineBuffer::updateIndicators(double speed, int iBufferSize) {
             (double)iBufferSize / m_trackSamplesOld,
             fractionalPlayposFromAbsolute(m_dSlipPosition),
             tempoTrackSeconds);
+
+    // TODO: Especially with long audio buffers, jitter is visible. This can be fixed by moving the
+    // ClockControl::updateIndicators into the waveform update loop which is synced with the display refresh rate.
+    // Via the visual play position it's possible to access to the sample that is currently played,
+    // and not the one that have been processed as in the current solution.
+    m_pClockControl->updateIndicators(speed * m_baserate_old, m_filepos_play, m_pSampleRate->get());
 }
 
 void EngineBuffer::hintReader(const double dRate) {

src/test/beatgridtest.cpp

@@ -76,7 +76,12 @@ TEST(BeatGridTest, TestNthBeatWhenOnBeat) {
 
     // Also test prev/next beat calculation.
     double prevBeat, nextBeat;
-    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat);
+    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat, true);
+    EXPECT_NEAR(position, prevBeat, kMaxBeatError);
+    EXPECT_NEAR(position + beatLength, nextBeat, kMaxBeatError);
+
+    // Also test prev/next beat calculation without snaping tolerance
+    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat, false);
     EXPECT_NEAR(position, prevBeat, kMaxBeatError);
     EXPECT_NEAR(position + beatLength, nextBeat, kMaxBeatError);
 
@@ -112,10 +117,15 @@ TEST(BeatGridTest, TestNthBeatWhenOnBeat_BeforeEpsilon) {
 
     // Also test prev/next beat calculation.
     double prevBeat, nextBeat;
-    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat);
+    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat, true);
     EXPECT_NEAR(kClosestBeat, prevBeat, kMaxBeatError);
     EXPECT_NEAR(kClosestBeat + beatLength, nextBeat, kMaxBeatError);
 
+    // Also test prev/next beat calculation without snaping tolerance
+    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat, false);
+    EXPECT_NEAR(kClosestBeat - beatLength, prevBeat, kMaxBeatError);
+    EXPECT_NEAR(kClosestBeat, nextBeat, kMaxBeatError);
+
     // Both previous and next beat should return the closest beat.
     EXPECT_NEAR(kClosestBeat, pGrid->findNextBeat(position), kMaxBeatError);
     EXPECT_NEAR(kClosestBeat, pGrid->findPrevBeat(position), kMaxBeatError);
@@ -148,7 +158,12 @@ TEST(BeatGridTest, TestNthBeatWhenOnBeat_AfterEpsilon) {
 
     // Also test prev/next beat calculation.
     double prevBeat, nextBeat;
-    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat);
+    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat, true);
+    EXPECT_NEAR(kClosestBeat, prevBeat, kMaxBeatError);
+    EXPECT_NEAR(kClosestBeat + beatLength, nextBeat, kMaxBeatError);
+
+    // Also test prev/next beat calculation without snaping tolerance
+    pGrid->findPrevNextBeats(position, &prevBeat, &nextBeat, false);
     EXPECT_NEAR(kClosestBeat, prevBeat, kMaxBeatError);
     EXPECT_NEAR(kClosestBeat + beatLength, nextBeat, kMaxBeatError);
 
@@ -185,7 +200,12 @@ TEST(BeatGridTest, TestNthBeatWhenNotOnBeat) {
 
     // Also test prev/next beat calculation
     double foundPrevBeat, foundNextBeat;
-    pGrid->findPrevNextBeats(position, &foundPrevBeat, &foundNextBeat);
+    pGrid->findPrevNextBeats(position, &foundPrevBeat, &foundNextBeat, true);
+    EXPECT_NEAR(previousBeat, foundPrevBeat, kMaxBeatError);
+    EXPECT_NEAR(nextBeat, foundNextBeat, kMaxBeatError);
+
+    // Also test prev/next beat calculation without snaping tolerance
+    pGrid->findPrevNextBeats(position, &foundPrevBeat, &foundNextBeat, false);
     EXPECT_NEAR(previousBeat, foundPrevBeat, kMaxBeatError);
     EXPECT_NEAR(nextBeat, foundNextBeat, kMaxBeatError);
 }