From ba9fe26dcd802322e03659f3faf578cbdaf1a273 Mon Sep 17 00:00:00 2001
From: Chris Cannam <cannam@all-day-breakfast.com>
Date: Fri, 24 Mar 2023 17:51:44 +0000
Subject: [PATCH] Never phase reset on silence in side channel, now that such
 resets are carried across

---
 src/finer/Guide.h         |  3 ++-
 src/finer/R3Stretcher.cpp | 11 +++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/finer/Guide.h b/src/finer/Guide.h
index 8f01c95..bfc5788 100644
--- a/src/finer/Guide.h
+++ b/src/finer/Guide.h
@@ -208,6 +208,7 @@ public:
                         int unityCount,
                         bool realtime,
                         bool tighterChannelLock,
+                        bool resetOnSilence,
                         Guidance &guidance) const {
 
         Profiler profiler("Guide::updateGuidance");
@@ -282,7 +283,7 @@ public:
         // the band ranges as well - in normal multi-window mode we
         // still have to do that, but we should do these first
         
-        if (meanMagnitude < 1.0e-6) {
+        if (resetOnSilence && meanMagnitude < 1.0e-6) {
             updateForSilence(guidance);
             return;
         }
diff --git a/src/finer/R3Stretcher.cpp b/src/finer/R3Stretcher.cpp
index 2608585..9055bb2 100644
--- a/src/finer/R3Stretcher.cpp
+++ b/src/finer/R3Stretcher.cpp
@@ -1303,6 +1303,15 @@ R3Stretcher::analyseChannel(int c, int inhop, int prevInhop, int prevOuthop)
         m_parameters.options & RubberBandStretcher::OptionChannelsTogether;
 
     double magMean = v_mean(classifyScale->mag.data() + 1, classify/2);
+
+    bool resetOnSilence = true;
+    if (useMidSide() && c == 1) {
+        // Do not phase reset on silence in the side channel - the
+        // reset is propagated across to the mid channel, giving
+        // constant resets for e.g. mono material in a stereo
+        // configuration
+        resetOnSilence = false;
+    }
     
     if (m_useReadahead) {
         m_guide.updateGuidance(ratio,
@@ -1317,6 +1326,7 @@ R3Stretcher::analyseChannel(int c, int inhop, int prevInhop, int prevOuthop)
                                m_unityCount,
                                isRealTime(),
                                tighterChannelLock,
+                               resetOnSilence,
                                cd->guidance);
     } else {
         m_guide.updateGuidance(ratio,
@@ -1331,6 +1341,7 @@ R3Stretcher::analyseChannel(int c, int inhop, int prevInhop, int prevOuthop)
                                m_unityCount,
                                isRealTime(),
                                tighterChannelLock,
+                               resetOnSilence,
                                cd->guidance);
     }