Add LogarithmicVolumeScale to VolumeScale enum.

Change-Id: I0b556b5f705825fc8c8135305bda4bc860ffbf14
Reviewed-by: Christian Stromme <christian.stromme@qt.io>

7 files changed, 159 insertions, 20 deletions

diff --git a/src/imports/multimedia/qdeclarativemultimediaglobal.cpp b/src/imports/multimedia/qdeclarativemultimediaglobal.cpp
index bb1b9c9d8..999f086d5 100644
--- a/src/imports/multimedia/qdeclarativemultimediaglobal.cpp
+++ b/src/imports/multimedia/qdeclarativemultimediaglobal.cpp
@@ -191,18 +191,20 @@ QJSValue QDeclarativeMultimediaGlobal::availableCameras() const
     Depending on the context, different scales are used to represent audio volume. All Qt Multimedia
     classes that have an audio volume use a linear scale, the reason is that the loudness of a
     speaker is controlled by modulating its voltage on a linear scale. The human ear on the other
-    hand, perceives loudness in a logarithmic way. That is why the decibel scale, being a logarithmic
-    scale, is typically used to define sound levels. UI volume controls in professional audio
-    applications usually use a decibel scale. The cubic scale is a computationally cheap
-    approximation of a logarithmic scale, most applications should use a cubic scale for their UI
-    volume controls.
+    hand, perceives loudness in a logarithmic way. Using a logarithmic scale for volume controls
+    is therefore appropriate in most applications. The decibel scale is logarithmic by nature and
+    is commonly used to define sound levels, it is usually used for UI volume controls in
+    professional audio applications. The cubic scale is a computationally cheap approximation of a
+    logarithmic scale, it provides more control over lower volume levels.
 
     Valid values for \a from and \a to are:
     \list
     \li QtMultimedia.LinearVolumeScale - Linear scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is
         full volume. All Qt Multimedia types that have an audio volume use a linear scale.
     \li QtMultimedia.CubicVolumeScale - Cubic scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is full
-        volume. UI volume controls should usually use a cubic scale.
+        volume.
+    \li QtMultimedia.LogarithmicVolumeScale - Logarithmic scale. \c 0.0 (0%) is silence and \c 1.0
+        (100%) is full volume. UI volume controls should usually use a logarithmic scale.
     \li QtMultimedia.DecibelVolumeScale - Decibel (dB, amplitude) logarithmic scale. \c -200 is
         silence and \c 0 is full volume.
     \endlist
@@ -216,7 +218,7 @@ QJSValue QDeclarativeMultimediaGlobal::availableCameras() const
         id: volumeSlider
 
         property real volume: QtMultimedia.convertVolume(volumeSlider.value,
-                                                         QtMultimedia.CubicVolumeScale,
+                                                         QtMultimedia.LogarithmicVolumeScale,
                                                          QtMultimedia.LinearVolumeScale)
     }
 
diff --git a/src/imports/multimedia/qdeclarativemultimediaglobal_p.h b/src/imports/multimedia/qdeclarativemultimediaglobal_p.h
index a8413cc09..101bd899a 100644
--- a/src/imports/multimedia/qdeclarativemultimediaglobal_p.h
+++ b/src/imports/multimedia/qdeclarativemultimediaglobal_p.h
@@ -70,6 +70,7 @@ public:
     enum VolumeScale {
         LinearVolumeScale = QAudio::LinearVolumeScale,
         CubicVolumeScale = QAudio::CubicVolumeScale,
+        LogarithmicVolumeScale = QAudio::LogarithmicVolumeScale,
         DecibelVolumeScale = QAudio::DecibelVolumeScale
     };
 
diff --git a/src/multimedia/audio/qaudio.cpp b/src/multimedia/audio/qaudio.cpp
index 426c984df..d4f89e898 100644
--- a/src/multimedia/audio/qaudio.cpp
+++ b/src/multimedia/audio/qaudio.cpp
@@ -44,6 +44,8 @@
 
 QT_BEGIN_NAMESPACE
 
+#define LOG100 4.60517018599
+
 static void qRegisterAudioMetaTypes()
 {
     qRegisterMetaType<QAudio::Error>();
@@ -118,13 +120,16 @@ Q_CONSTRUCTOR_FUNCTION(qRegisterAudioMetaTypes)
 
     This enum defines the different audio volume scales.
 
-    \value LinearVolumeScale     Linear scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is full
-                                 volume. All Qt Multimedia classes that have an audio volume use a
-                                 linear scale.
-    \value CubicVolumeScale      Cubic scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is full
-                                 volume. UI volume controls should usually use a cubic scale.
-    \value DecibelVolumeScale    Decibel (dB, amplitude) logarithmic scale. \c -200 is silence and
-                                 \c 0 is full volume.
+    \value LinearVolumeScale        Linear scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is full
+                                    volume. All Qt Multimedia classes that have an audio volume use
+                                    a linear scale.
+    \value CubicVolumeScale         Cubic scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is full
+                                    volume.
+    \value LogarithmicVolumeScale   Logarithmic Scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is
+                                    full volume. UI volume controls should usually use a logarithmic
+                                    scale.
+    \value DecibelVolumeScale       Decibel (dB, amplitude) logarithmic scale. \c -200 is silence
+                                    and \c 0 is full volume.
 
     \since 5.8
     \sa QAudio::convertVolume()
@@ -141,11 +146,11 @@ namespace QAudio
     Depending on the context, different scales are used to represent audio volume. All Qt Multimedia
     classes that have an audio volume use a linear scale, the reason is that the loudness of a
     speaker is controlled by modulating its voltage on a linear scale. The human ear on the other
-    hand, perceives loudness in a logarithmic way. That is why the decibel scale, being a logarithmic
-    scale, is typically used to define sound levels. UI volume controls in professional audio
-    applications usually use a decibel scale. The cubic scale is a computationally cheap
-    approximation of a logarithmic scale, most applications should use a cubic scale for their UI
-    volume controls.
+    hand, perceives loudness in a logarithmic way. Using a logarithmic scale for volume controls
+    is therefore appropriate in most applications. The decibel scale is logarithmic by nature and
+    is commonly used to define sound levels, it is usually used for UI volume controls in
+    professional audio applications. The cubic scale is a computationally cheap approximation of a
+    logarithmic scale, it provides more control over lower volume levels.
 
     The following example shows how to convert the volume value from a slider control before passing
     it to a QMediaPlayer. As a result, the perceived increase in volume is the same when increasing
@@ -167,6 +172,8 @@ qreal convertVolume(qreal volume, VolumeScale from, VolumeScale to)
             return volume;
         case CubicVolumeScale:
             return qPow(volume, qreal(1 / 3.0));
+        case LogarithmicVolumeScale:
+            return 1 - std::exp(-volume * LOG100);
         case DecibelVolumeScale:
             if (volume < 0.001)
                 return qreal(-200);
@@ -181,6 +188,8 @@ qreal convertVolume(qreal volume, VolumeScale from, VolumeScale to)
             return volume * volume * volume;
         case CubicVolumeScale:
             return volume;
+        case LogarithmicVolumeScale:
+            return 1 - std::exp(-volume * volume * volume * LOG100);
         case DecibelVolumeScale:
             if (volume < 0.001)
                 return qreal(-200);
@@ -188,12 +197,41 @@ qreal convertVolume(qreal volume, VolumeScale from, VolumeScale to)
                 return qreal(3.0 * 20.0) * std::log10(volume);
         }
         break;
+    case LogarithmicVolumeScale:
+        volume = qMax(qreal(0), volume);
+        switch (to) {
+        case LinearVolumeScale:
+            if (volume > 0.99)
+                return 1;
+            else
+                return -std::log(1 - volume) / LOG100;
+        case CubicVolumeScale:
+            if (volume > 0.99)
+                return 1;
+            else
+                return qPow(-std::log(1 - volume) / LOG100, qreal(1 / 3.0));
+        case LogarithmicVolumeScale:
+            return volume;
+        case DecibelVolumeScale:
+            if (volume < 0.001)
+                return qreal(-200);
+            else if (volume > 0.99)
+                return 0;
+            else
+                return qreal(20.0) * std::log10(-std::log(1 - volume) / LOG100);
+        }
+        break;
     case DecibelVolumeScale:
         switch (to) {
         case LinearVolumeScale:
             return qPow(qreal(10.0), volume / qreal(20.0));
         case CubicVolumeScale:
             return qPow(qreal(10.0), volume / qreal(3.0 * 20.0));
+        case LogarithmicVolumeScale:
+            if (qFuzzyIsNull(volume))
+                return 1;
+            else
+                return 1 - std::exp(-qPow(qreal(10.0), volume / qreal(20.0)) * LOG100);
         case DecibelVolumeScale:
             return volume;
         }
@@ -316,6 +354,9 @@ QDebug operator<<(QDebug dbg, QAudio::VolumeScale scale)
     case QAudio::CubicVolumeScale:
         dbg << "CubicVolumeScale";
         break;
+    case QAudio::LogarithmicVolumeScale:
+        dbg << "LogarithmicVolumeScale";
+        break;
     case QAudio::DecibelVolumeScale:
         dbg << "DecibelVolumeScale";
         break;
diff --git a/src/multimedia/audio/qaudio.h b/src/multimedia/audio/qaudio.h
index 9bbc6cf22..457a3b621 100644
--- a/src/multimedia/audio/qaudio.h
+++ b/src/multimedia/audio/qaudio.h
@@ -74,6 +74,7 @@ namespace QAudio
     enum VolumeScale {
         LinearVolumeScale,
         CubicVolumeScale,
+        LogarithmicVolumeScale,
         DecibelVolumeScale
     };
 
diff --git a/src/multimedia/doc/snippets/multimedia-snippets/audio.cpp b/src/multimedia/doc/snippets/multimedia-snippets/audio.cpp
index 736d1b306..9646b708e 100644
--- a/src/multimedia/doc/snippets/multimedia-snippets/audio.cpp
+++ b/src/multimedia/doc/snippets/multimedia-snippets/audio.cpp
@@ -257,7 +257,7 @@ void applyVolume(int volumeSliderValue)
     // volumeSliderValue is in the range [0..100]
 
     qreal linearVolume = QAudio::convertVolume(volumeSliderValue / qreal(100.0),
-                                               QAudio::CubicVolumeScale,
+                                               QAudio::LogarithmicVolumeScale,
                                                QAudio::LinearVolumeScale);
 
     player.setVolume(qRound(linearVolume * 100));
diff --git a/tests/auto/unit/qaudionamespace/tst_qaudionamespace.cpp b/tests/auto/unit/qaudionamespace/tst_qaudionamespace.cpp
index 7907cd290..5cd89ec3e 100644
--- a/tests/auto/unit/qaudionamespace/tst_qaudionamespace.cpp
+++ b/tests/auto/unit/qaudionamespace/tst_qaudionamespace.cpp
@@ -152,6 +152,13 @@ void tst_QAudioNamespace::convertVolume_data()
     QTest::newRow("0.72 from linear to cubic") << qreal(0.72) << QAudio::LinearVolumeScale << QAudio::CubicVolumeScale << qreal(0.89);
     QTest::newRow("1.0 from linear to cubic") << qreal(1.0) << QAudio::LinearVolumeScale << QAudio::CubicVolumeScale << qreal(1.0);
 
+    QTest::newRow("-1.0 from linear to logarithmic") << qreal(-1.0) << QAudio::LinearVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("0.0 from linear to logarithmic") << qreal(0.0) << QAudio::LinearVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("0.33 from linear to logarithmic") << qreal(0.33) << QAudio::LinearVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.78);
+    QTest::newRow("0.5 from linear to logarithmic") << qreal(0.5) << QAudio::LinearVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.9);
+    QTest::newRow("0.72 from linear to logarithmic") << qreal(0.72) << QAudio::LinearVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.96);
+    QTest::newRow("1.0 from linear to logarithmic") << qreal(1.0) << QAudio::LinearVolumeScale << QAudio::LogarithmicVolumeScale << qreal(1.0);
+
     QTest::newRow("-1.0 from linear to decibel") << qreal(-1.0) << QAudio::LinearVolumeScale << QAudio::DecibelVolumeScale << qreal(-200);
     QTest::newRow("0.0 from linear to decibel") << qreal(0.0) << QAudio::LinearVolumeScale << QAudio::DecibelVolumeScale << qreal(-200);
     QTest::newRow("0.33 from linear to decibel") << qreal(0.33) << QAudio::LinearVolumeScale << QAudio::DecibelVolumeScale << qreal(-9.63);
@@ -171,6 +178,13 @@ void tst_QAudioNamespace::convertVolume_data()
     QTest::newRow("0.5 from cubic to cubic") << qreal(0.5) << QAudio::CubicVolumeScale << QAudio::CubicVolumeScale << qreal(0.5);
     QTest::newRow("1.0 from cubic to cubic") << qreal(1.0) << QAudio::CubicVolumeScale << QAudio::CubicVolumeScale << qreal(1.0);
 
+    QTest::newRow("-1.0 from cubic to logarithmic") << qreal(-1.0) << QAudio::CubicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("0.0 from cubic to logarithmic") << qreal(0.0) << QAudio::CubicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("0.33 from cubic to logarithmic") << qreal(0.33) << QAudio::CubicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.15);
+    QTest::newRow("0.5 from cubic to logarithmic") << qreal(0.5) << QAudio::CubicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.44);
+    QTest::newRow("0.72 from cubic to logarithmic") << qreal(0.72) << QAudio::CubicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.82);
+    QTest::newRow("1.0 from cubic to logarithmic") << qreal(1.0) << QAudio::CubicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(1.0);
+
     QTest::newRow("-1.0 from cubic to decibel") << qreal(-1.0) << QAudio::CubicVolumeScale << QAudio::DecibelVolumeScale << qreal(-200);
     QTest::newRow("0.0 from cubic to decibel") << qreal(0.0) << QAudio::CubicVolumeScale << QAudio::DecibelVolumeScale << qreal(-200);
     QTest::newRow("0.33 from cubic to decibel") << qreal(0.33) << QAudio::CubicVolumeScale << QAudio::DecibelVolumeScale << qreal(-28.89);
@@ -178,6 +192,32 @@ void tst_QAudioNamespace::convertVolume_data()
     QTest::newRow("0.72 from cubic to decibel") << qreal(0.72) << QAudio::CubicVolumeScale << QAudio::DecibelVolumeScale << qreal(-8.56);
     QTest::newRow("1.0 from cubic to decibel") << qreal(1.0) << QAudio::CubicVolumeScale << QAudio::DecibelVolumeScale << qreal(0);
 
+    QTest::newRow("-1.0 from logarithmic to linear") << qreal(-1.0) << QAudio::LogarithmicVolumeScale << QAudio::LinearVolumeScale << qreal(0.0);
+    QTest::newRow("0.0 from logarithmic to linear") << qreal(0.0) << QAudio::LogarithmicVolumeScale << QAudio::LinearVolumeScale << qreal(0.0);
+    QTest::newRow("0.33 from logarithmic to linear") << qreal(0.33) << QAudio::LogarithmicVolumeScale << QAudio::LinearVolumeScale << qreal(0.09);
+    QTest::newRow("0.5 from logarithmic to linear") << qreal(0.5) << QAudio::LogarithmicVolumeScale << QAudio::LinearVolumeScale << qreal(0.15);
+    QTest::newRow("0.72 from logarithmic to linear") << qreal(0.72) << QAudio::LogarithmicVolumeScale << QAudio::LinearVolumeScale << qreal(0.28);
+    QTest::newRow("1.0 from logarithmic to linear") << qreal(1.0) << QAudio::LogarithmicVolumeScale << QAudio::LinearVolumeScale << qreal(1.0);
+
+    QTest::newRow("-1.0 from logarithmic to cubic") << qreal(-1.0) << QAudio::LogarithmicVolumeScale << QAudio::CubicVolumeScale << qreal(0.0);
+    QTest::newRow("0.0 from logarithmic to cubic") << qreal(0.0) << QAudio::LogarithmicVolumeScale << QAudio::CubicVolumeScale << qreal(0.0);
+    QTest::newRow("0.33 from logarithmic to cubic") << qreal(0.33) << QAudio::LogarithmicVolumeScale << QAudio::CubicVolumeScale << qreal(0.44);
+    QTest::newRow("0.5 from logarithmic to cubic") << qreal(0.5) << QAudio::LogarithmicVolumeScale << QAudio::CubicVolumeScale << qreal(0.53);
+    QTest::newRow("0.72 from logarithmic to cubic") << qreal(0.72) << QAudio::LogarithmicVolumeScale << QAudio::CubicVolumeScale << qreal(0.65);
+    QTest::newRow("1.0 from logarithmic to cubic") << qreal(1.0) << QAudio::LogarithmicVolumeScale << QAudio::CubicVolumeScale << qreal(1.0);
+
+    QTest::newRow("-1.0 from logarithmic to logarithmic") << qreal(-1.0) << QAudio::LogarithmicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("0.0 from logarithmic to logarithmic") << qreal(0.0) << QAudio::LogarithmicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("0.5 from logarithmic to logarithmic") << qreal(0.5) << QAudio::LogarithmicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.5);
+    QTest::newRow("1.0 from logarithmic to logarithmic") << qreal(1.0) << QAudio::LogarithmicVolumeScale << QAudio::LogarithmicVolumeScale << qreal(1.0);
+
+    QTest::newRow("-1.0 from logarithmic to decibel") << qreal(-1.0) << QAudio::LogarithmicVolumeScale << QAudio::DecibelVolumeScale << qreal(-200);
+    QTest::newRow("0.0 from logarithmic to decibel") << qreal(0.0) << QAudio::LogarithmicVolumeScale << QAudio::DecibelVolumeScale << qreal(-200);
+    QTest::newRow("0.33 from logarithmic to decibel") << qreal(0.33) << QAudio::LogarithmicVolumeScale << QAudio::DecibelVolumeScale << qreal(-21.21);
+    QTest::newRow("0.5 from logarithmic to decibel") << qreal(0.5) << QAudio::LogarithmicVolumeScale << QAudio::DecibelVolumeScale << qreal(-16.45);
+    QTest::newRow("0.72 from logarithmic to decibel") << qreal(0.72) << QAudio::LogarithmicVolumeScale << QAudio::DecibelVolumeScale << qreal(-11.17);
+    QTest::newRow("1.0 from logarithmic to decibel") << qreal(1.0) << QAudio::LogarithmicVolumeScale << QAudio::DecibelVolumeScale << qreal(0);
+
     QTest::newRow("-1000 from decibel to linear") << qreal(-1000.0) << QAudio::DecibelVolumeScale << QAudio::LinearVolumeScale << qreal(0.0);
     QTest::newRow("-200 from decibel to linear") << qreal(-200.0) << QAudio::DecibelVolumeScale << QAudio::LinearVolumeScale << qreal(0.0);
     QTest::newRow("-40 from decibel to linear") << qreal(-40.0) << QAudio::DecibelVolumeScale << QAudio::LinearVolumeScale << qreal(0.01);
@@ -192,6 +232,13 @@ void tst_QAudioNamespace::convertVolume_data()
     QTest::newRow("-5 from decibel to cubic") << qreal(-5.0) << QAudio::DecibelVolumeScale << QAudio::CubicVolumeScale << qreal(0.83);
     QTest::newRow("0 from decibel to cubic") << qreal(0.0) << QAudio::DecibelVolumeScale << QAudio::CubicVolumeScale << qreal(1.0);
 
+    QTest::newRow("-1000 from decibel to logarithmic") << qreal(-1000.0) << QAudio::DecibelVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("-200 from decibel to logarithmic") << qreal(-200.0) << QAudio::DecibelVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.0);
+    QTest::newRow("-40 from decibel to logarithmic") << qreal(-40.0) << QAudio::DecibelVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.05);
+    QTest::newRow("-10 from decibel to logarithmic") << qreal(-10.0) << QAudio::DecibelVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.77);
+    QTest::newRow("-5 from decibel to logarithmic") << qreal(-5.0) << QAudio::DecibelVolumeScale << QAudio::LogarithmicVolumeScale << qreal(0.92);
+    QTest::newRow("0 from decibel to logarithmic") << qreal(0.0) << QAudio::DecibelVolumeScale << QAudio::LogarithmicVolumeScale << qreal(1.0);
+
     QTest::newRow("-1000 from decibel to decibel") << qreal(-1000.0) << QAudio::DecibelVolumeScale << QAudio::DecibelVolumeScale << qreal(-1000.0);
     QTest::newRow("-200 from decibel to decibel") << qreal(-200.0) << QAudio::DecibelVolumeScale << QAudio::DecibelVolumeScale << qreal(-200.0);
     QTest::newRow("-30 from decibel to decibel") << qreal(-30.0) << QAudio::DecibelVolumeScale << QAudio::DecibelVolumeScale << qreal(-30.0);
diff --git a/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml b/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml
index 22f4bf604..e44c68a29 100644
--- a/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml
+++ b/tests/auto/unit/qdeclarativemultimediaglobal/tst_qdeclarativemultimediaglobal.qml
@@ -77,6 +77,13 @@ TestCase {
             { tag: "0.72 from linear to cubic", input: 0.72, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.89 },
             { tag: "1.0 from linear to cubic", input: 1.0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 1.0 },
 
+            { tag: "-1.0 from linear to logarithmic", input: -1, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from linear to logarithmic", input: 0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "0.33 from linear to logarithmic", input: 0.33, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.78 },
+            { tag: "0.5 from linear to logarithmic", input: 0.5, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.9 },
+            { tag: "0.72 from linear to logarithmic", input: 0.72, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.96 },
+            { tag: "1.0 from linear to logarithmic", input: 1.0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 1.0 },
+
             { tag: "-1.0 from linear to decibel", input: -1, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
             { tag: "0.0 from linear to decibel", input: 0, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
             { tag: "0.33 from linear to decibel", input: 0.33, from: QtMultimedia.LinearVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -9.63 },
@@ -96,6 +103,13 @@ TestCase {
             { tag: "0.5 from cubic to cubic", input: 0.5, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.5 },
             { tag: "1.0 from cubic to cubic", input: 1.0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 1.0 },
 
+            { tag: "-1.0 from cubic to logarithmic", input: -1, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from cubic to logarithmic", input: 0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "0.33 from cubic to logarithmic", input: 0.33, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.15 },
+            { tag: "0.5 from cubic to logarithmic", input: 0.5, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.44 },
+            { tag: "0.72 from cubic to logarithmic", input: 0.72, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.82 },
+            { tag: "1.0 from cubic to logarithmic", input: 1.0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 1 },
+
             { tag: "-1.0 from cubic to decibel", input: -1, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
             { tag: "0.0 from cubic to decibel", input: 0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
             { tag: "0.33 from cubic to decibel", input: 0.33, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -28.89 },
@@ -103,6 +117,32 @@ TestCase {
             { tag: "0.72 from cubic to decibel", input: 0.72, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -8.56 },
             { tag: "1.0 from cubic to decibel", input: 1.0, from: QtMultimedia.CubicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: 0 },
 
+            { tag: "-1.0 from logarithmic to linear", input: -1, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from logarithmic to linear", input: 0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
+            { tag: "0.33 from logarithmic to linear", input: 0.33, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.09 },
+            { tag: "0.5 from logarithmic to linear", input: 0.5, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.15 },
+            { tag: "0.72 from logarithmic to linear", input: 0.72, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.28 },
+            { tag: "1.0 from logarithmic to linear", input: 1.0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 1.0 },
+
+            { tag: "-1.0 from logarithmic to cubic", input: -1, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from logarithmic to cubic", input: 0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0 },
+            { tag: "0.33 from logarithmic to cubic", input: 0.33, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.44 },
+            { tag: "0.5 from logarithmic to cubic", input: 0.5, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.53 },
+            { tag: "0.72 from logarithmic to cubic", input: 0.72, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.65 },
+            { tag: "1.0 from logarithmic to cubic", input: 1.0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 1.0 },
+
+            { tag: "-1.0 from logarithmic to logarithmic", input: -1, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "0.0 from logarithmic to logarithmic", input: 0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "0.5 from logarithmic to logarithmic", input: 0.5, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.5 },
+            { tag: "1.0 from logarithmic to logarithmic", input: 1.0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 1.0 },
+
+            { tag: "-1.0 from logarithmic to decibel", input: -1, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
+            { tag: "0.0 from logarithmic to decibel", input: 0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
+            { tag: "0.33 from logarithmic to decibel", input: 0.33, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -21.21 },
+            { tag: "0.5 from logarithmic to decibel", input: 0.5, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -16.45 },
+            { tag: "0.72 from logarithmic to decibel", input: 0.72, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -11.17 },
+            { tag: "1.0 from logarithmic to decibel", input: 1.0, from: QtMultimedia.LogarithmicVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: 0 },
+
             { tag: "-1000 from decibel to linear", input: -1000, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
             { tag: "-200 from decibel to linear", input: -200, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0 },
             { tag: "-40 from decibel to linear", input: -40, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LinearVolumeScale, expectedOutput: 0.01 },
@@ -117,6 +157,13 @@ TestCase {
             { tag: "-5 from decibel to cubic", input: -5, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 0.83 },
             { tag: "0 from decibel to cubic", input: 0, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.CubicVolumeScale, expectedOutput: 1 },
 
+            { tag: "-1000 from decibel to logarithmic", input: -1000, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "-200 from decibel to logarithmic", input: -200, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0 },
+            { tag: "-40 from decibel to logarithmic", input: -40, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.05 },
+            { tag: "-10 from decibel to logarithmic", input: -10, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.77 },
+            { tag: "-5 from decibel to logarithmic", input: -5, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 0.92 },
+            { tag: "0 from decibel to logarithmic", input: 0, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.LogarithmicVolumeScale, expectedOutput: 1 },
+
             { tag: "-1000 from decibel to decibel", input: -1000, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -1000 },
             { tag: "-200 from decibel to decibel", input: -200, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -200 },
             { tag: "-30 from decibel to decibel", input: -30, from: QtMultimedia.DecibelVolumeScale, to: QtMultimedia.DecibelVolumeScale, expectedOutput: -30 },