From 2d831ae96852ed9474ad2dfbd338b914ce10ed2f Mon Sep 17 00:00:00 2001
From: Antoine C <mixxx@acolombier.dev>
Date: Sun, 9 Jun 2024 18:44:15 +0100
Subject: [PATCH] Rewording RB multi threading to clarify the stereo split into
 mono

---
 .../bufferscalers/rubberbandwrapper.cpp       | 17 ++++++++--
 src/preferences/dialog/dlgprefsound.cpp       | 31 ++++++++++++-------
 src/preferences/dialog/dlgprefsounddlg.ui     |  3 --
 3 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/src/engine/bufferscalers/rubberbandwrapper.cpp b/src/engine/bufferscalers/rubberbandwrapper.cpp
index aec0f0304f2..ede9a60a70f 100644
--- a/src/engine/bufferscalers/rubberbandwrapper.cpp
+++ b/src/engine/bufferscalers/rubberbandwrapper.cpp
@@ -14,8 +14,21 @@ namespace {
 /// The function is used to compute the best number of channel per RB task,
 /// depending of the number of channels and available worker. This allows
 /// hardware if will less than 8 core to adjust the task distribution in the
-/// most optimum way. The following table provide the expected number of channel
-/// per task when using multi threading globally.
+/// most optimum way.
+///
+/// The following table provide the expected number of channel per task with
+/// stereo processing (the default behaviour)
+///
+///  | NbOfCore | Stereo | Stem |
+///  |----------|--------|------|
+///  | 1        | 2      | 8    |
+///  | 2        | 2      | 4    |
+///  | 3        | 2      | 2    |
+///  | 4        | 2      | 2    |
+///
+/// The following table provide the expected number of channel per task when the
+/// user has explicitly requested stereo channel to be processed as mono
+/// channels.
 ///
 ///  | NbOfCore | Stereo | Stem |
 ///  |----------|--------|------|
diff --git a/src/preferences/dialog/dlgprefsound.cpp b/src/preferences/dialog/dlgprefsound.cpp
index f5faf4fb9d2..925f55f0dfe 100644
--- a/src/preferences/dialog/dlgprefsound.cpp
+++ b/src/preferences/dialog/dlgprefsound.cpp
@@ -37,17 +37,21 @@ bool soundItemAlreadyExists(const AudioPath& output, const QWidget& widget) {
 }
 
 #ifdef __RUBBERBAND__
-const QString kKeylockMultiThreadedAvailable =
-        QStringLiteral("<p><span style=\"font-weight:600;\">") +
+const QString kKeylockMultiThreadedAvailable = QStringLiteral("<p>") +
+        QObject::tr(
+                "Distribute stereo channels into mono channels processed in "
+                "parallel.") +
+        QStringLiteral("</p><p><span style=\"font-weight:600;\">") +
         QObject::tr("Warning!") + QStringLiteral("</span></p><p>") +
         QObject::tr(
-                "Using multi "
-                "threading may result in pitch and tone imperfection, and this "
+                "Processing stereo signal as mono channel "
+                "may result in pitch and tone imperfection, and this "
                 "is "
                 "mono-incompatible, due to third party limitations.") +
-        QStringLiteral("\n") +
+        QStringLiteral("</p><p>") +
         QObject::tr(
-                "When disabled, multi threading will still be used on stem track if possible.") +
+                "Note that stem tracks will always be processed in parallel, "
+                "as individual stereo channels.") +
         QStringLiteral("</p>");
 const QString kKeylockMultiThreadedUnavailableMono = QStringLiteral("<i>") +
         QObject::tr(
@@ -308,6 +312,7 @@ void DlgPrefSound::slotUpdate() {
     // for a prefs rewrite -- bkgood
     m_bSkipConfigClear = true;
     loadSettings();
+    settingChanged();
     checkLatencyCompensation();
     m_bSkipConfigClear = false;
     m_settingsModified = false;
@@ -760,12 +765,14 @@ void DlgPrefSound::updateKeylockMultithreading(bool enabled) {
     QMessageBox msg;
     msg.setIcon(QMessageBox::Warning);
     msg.setWindowTitle(tr("Are you sure?"));
-    msg.setText(QStringLiteral("<p>%1</p><p>%2</p>")
-                        .arg(tr("Using multi threading result in a loss of "
-                                "mono compatibility and a diffuse stereo "
-                                "image. It is not recommended during "
-                                "broadcasting or recording."),
-                                tr("Are you sure you wish to proceed?")));
+    msg.setText(
+            QStringLiteral("<p>%1</p><p>%2</p>")
+                    .arg(tr("Distribute stereo channels into mono channels for "
+                            "parallel processing will result in a loss of "
+                            "mono compatibility and a diffuse stereo "
+                            "image. It is not recommended during "
+                            "broadcasting or recording."),
+                            tr("Are you sure you wish to proceed?")));
     QPushButton* pNoBtn = msg.addButton(tr("No"), QMessageBox::AcceptRole);
     QPushButton* pYesBtn = msg.addButton(
             tr("Yes, I know what I am doing"), QMessageBox::RejectRole);
diff --git a/src/preferences/dialog/dlgprefsounddlg.ui b/src/preferences/dialog/dlgprefsounddlg.ui
index ca0bebbd380..5ca5ac41712 100644
--- a/src/preferences/dialog/dlgprefsounddlg.ui
+++ b/src/preferences/dialog/dlgprefsounddlg.ui
@@ -231,9 +231,6 @@
            <verstretch>0</verstretch>
           </sizepolicy>
          </property>
-         <property name="toolTip">
-          <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;&lt;span style=&quot; font-weight:600;&quot;&gt;Warning!&lt;/span&gt;&lt;/p&gt;&lt;p&gt;Using multi threading may result in pitch and tone imperfaction depending of the platform, leading to mono-incompatibiltiy, due to third party limitations. &lt;/p&gt;&lt;p&gt;&lt;br/&gt;&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
-         </property>
          <property name="text">
           <string>Multi-threaded</string>
          </property>