From 6749d5b6fab13a7aa0df0fc782410a8c278399b4 Mon Sep 17 00:00:00 2001
From: Leland Lucius <github@homerow.net>
Date: Fri, 18 Sep 2020 09:24:45 -0500
Subject: [PATCH] Bug 1215 - Incorrect splits produced by Change Tempo with
 leading whitespace

---
 src/effects/SBSMSEffect.cpp | 46 +++++++++++++++++++++++++++++++++----
 src/effects/SBSMSEffect.h   |  2 ++
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/src/effects/SBSMSEffect.cpp b/src/effects/SBSMSEffect.cpp
index 600b22707..07b9e17d7 100644
--- a/src/effects/SBSMSEffect.cpp
+++ b/src/effects/SBSMSEffect.cpp
@@ -19,6 +19,7 @@ effect that uses SBSMS to do its processing (TimeScale)
 #include <math.h>
 
 #include "../LabelTrack.h"
+#include "../WaveClip.h"
 #include "../WaveTrack.h"
 #include "TimeWarper.h"
 
@@ -426,12 +427,9 @@ bool EffectSBSMS::Process()
             if(rightTrack)
                rb.outputRightTrack->Flush();
 
-            leftTrack->ClearAndPaste(mCurT0, mCurT1, rb.outputLeftTrack.get(),
-                                     true, false, warper.get());
-
+            Finalize(leftTrack, rb.outputLeftTrack.get(), warper.get());
             if(rightTrack)
-               rightTrack->ClearAndPaste(mCurT0, mCurT1, rb.outputRightTrack.get(),
-                                         true, false, warper.get());
+               Finalize(rightTrack, rb.outputRightTrack.get(), warper.get());
          }
          mCurTrackNum++;
       },
@@ -454,4 +452,42 @@ bool EffectSBSMS::Process()
    return bGoodResult;
 }
 
+void EffectSBSMS::Finalize(WaveTrack* orig, WaveTrack* out, const TimeWarper *warper)
+{
+   // Silenced samples will be inserted in gaps between clips, so capture where these
+   // gaps are for later deletion
+   std::vector<std::pair<double, double>> gaps;
+   double last = 0.0;
+   auto clips = orig->SortedClipArray();
+   auto front = clips.front();
+   auto back = clips.back();
+   for (auto &clip : clips) {
+      auto st = clip->GetStartTime();
+      auto et = clip->GetEndTime();
+
+      if (st >= mCurT0 || et < mCurT1) {
+         if (mCurT0 < st && clip == front) {
+            gaps.push_back(std::make_pair(mCurT0, st));
+         }
+         if (mCurT1 > et && clip == back) {
+            gaps.push_back(std::make_pair(et, mCurT1));
+         }
+         if (last >= mCurT0) {
+            gaps.push_back(std::make_pair(last, st));
+         }
+      }
+      last = et;
+   }
+
+   // Take the output track and insert it in place of the original sample data
+   orig->ClearAndPaste(mCurT0, mCurT1, out, true, true, warper);
+
+   // Finally, recreate the gaps
+   for (auto gap : gaps) {
+      auto st = orig->LongSamplesToTime(orig->TimeToLongSamples(gap.first));
+      auto et = orig->LongSamplesToTime(orig->TimeToLongSamples(gap.second));
+      orig->SplitDelete(warper->Warp(st), warper->Warp(et));
+   }
+}
+
 #endif
diff --git a/src/effects/SBSMSEffect.h b/src/effects/SBSMSEffect.h
index 784818dfb..dc8f0f22f 100644
--- a/src/effects/SBSMSEffect.h
+++ b/src/effects/SBSMSEffect.h
@@ -45,6 +45,8 @@ protected:
 
 private:
    bool ProcessLabelTrack(LabelTrack *track);
+   void Finalize(WaveTrack* orig, WaveTrack* out, const TimeWarper *warper);
+
    double rateStart, rateEnd, pitchStart, pitchEnd;
    bool bLinkRatePitch, bRateReferenceInput, bPitchReferenceInput;
    SlideType rateSlideType;