Don't change the internal baseBpm away from the value adopted from a deck

2 files changed, 5 insertions, 2 deletions

diff --git a/src/engine/sync/internalclock.cpp b/src/engine/sync/internalclock.cpp
index d12eebfdf4..f36d2136a3 100644
--- a/src/engine/sync/internalclock.cpp
+++ b/src/engine/sync/internalclock.cpp
@@ -138,7 +138,7 @@ void InternalClock::setMasterParams(double beatDistance, double baseBpm, double
     if (kLogger.traceEnabled()) {
         kLogger.trace() << "InternalClock::setMasterParams" << beatDistance << baseBpm << bpm;
     }
-    if (bpm == 0) {
+    if (bpm <= 0.0 || baseBpm <= 0.0) {
         return;
     }
     m_dBaseBpm = baseBpm;
@@ -147,7 +147,6 @@ void InternalClock::setMasterParams(double beatDistance, double baseBpm, double
 }
 
 void InternalClock::slotBpmChanged(double bpm) {
-    m_dBaseBpm = bpm;
     updateBeatLength(m_iOldSampleRate, bpm);
     if (!isSynchronized()) {
         return;
diff --git a/src/engine/sync/internalclock.h b/src/engine/sync/internalclock.h
index ab05889579..735bdd8536 100644
--- a/src/engine/sync/internalclock.h
+++ b/src/engine/sync/internalclock.h
@@ -73,6 +73,10 @@ class InternalClock : public QObject, public Clock, public Syncable {
 
     int m_iOldSampleRate;
     double m_dOldBpm;
+
+    // This is the BPM value at unity adopted when sync is enabled.
+    // It is used to relate the followers and must not change when
+    // the bpm is adjusted to avoid sudden double/half rate changes.
     double m_dBaseBpm;
 
     // The internal clock rate is stored in terms of samples per beat.