Don't fetch frame for audiospectrum if it is hidden

src/mainwindow.cpp

@@ -328,6 +328,9 @@ void MainWindow::init()
     // Audio spectrum scope
     m_audioSpectrum = new AudioGraphSpectrum(pCore->monitorManager());
     QDockWidget *spectrumDock = addDock(i18n("Audio Spectrum"), QStringLiteral("audiospectrum"), m_audioSpectrum);
+    connect(spectrumDock, &QDockWidget::visibilityChanged, [&](bool visible) {
+        m_audioSpectrum->dockVisible(visible);
+    });
     // Close library and audiospectrum on first run
     screenGrabDock->close();
     libraryDock->close();

src/monitor/scopes/audiographspectrum.cpp

@@ -303,7 +303,7 @@ AudioGraphSpectrum::AudioGraphSpectrum(MonitorManager *manager, QWidget *parent)
     QAction *a = new QAction(i18n("Enable Audio Spectrum"), this);
     a->setCheckable(true);
     a->setChecked(KdenliveSettings::enableaudiospectrum());
-    if (KdenliveSettings::enableaudiospectrum()) {
+    if (KdenliveSettings::enableaudiospectrum() && isVisible()) {
         connect(m_manager, &MonitorManager::frameDisplayed, this, &ScopeWidget::onNewFrame, Qt::UniqueConnection);
     }
     connect(a, &QAction::triggered, this, &AudioGraphSpectrum::activate);
@@ -317,6 +317,17 @@ AudioGraphSpectrum::~AudioGraphSpectrum()
     delete m_filter;
 }
 
+void AudioGraphSpectrum::dockVisible(bool visible)
+{
+    if (KdenliveSettings::enableaudiospectrum())  {
+        if (!visible) {
+            disconnect(m_manager, &MonitorManager::frameDisplayed, this, &ScopeWidget::onNewFrame);
+        } else {
+            connect(m_manager, &MonitorManager::frameDisplayed, this, &ScopeWidget::onNewFrame);
+        }
+    }
+}
+
 void AudioGraphSpectrum::activate(bool enable)
 {
     if (enable) {

src/monitor/scopes/audiographspectrum.h

@@ -80,6 +80,7 @@ class AudioGraphSpectrum : public ScopeWidget
 public:
     AudioGraphSpectrum(MonitorManager *manager, QWidget *parent = nullptr);
     ~AudioGraphSpectrum() override;
+    void dockVisible(bool visible);
 
 private:
     MonitorManager *m_manager;