Correctly set audio flag for generator clips (don't pretend we have an audio track when we don't)

Related to !546

data/generators/count.xml

@@ -13,7 +13,7 @@
 		  <paramlistdisplay>Seconds to 0,Seconds to 1,Frames,Timecode,Clock</paramlistdisplay>
 		  <name>Counter Style</name>
         </parameter>
-        <parameter type="list" name="sound" default="silent" paramlist="silent;2pop;frame0">
+        <parameter type="list" name="sound" default="silent" paramlist="silent;2pop;frame0" audio="2pop;frame0">
 		  <paramlistdisplay>Silent,1kHz beep before end,1kHz beep each second</paramlistdisplay>
 		  <name>Sound</name>
         </parameter>

data/generators/noise.xml

@@ -1,5 +1,5 @@
 <!DOCTYPE kpartgui>
-<generator tag="noise" id="noise">
+<generator tag="noise" id="noise" type="audio;video">
 	<name>White Noise</name>
 	<description>White noise producer</description>
 	<author>Charles Yates</author>

src/bin/generators/generators.cpp

@@ -79,6 +79,26 @@ Generators::Generators(const QString &path, QWidget *parent)
         connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
         lay->addWidget(buttonBox);
         m_timePos->setValue(KdenliveSettings::color_duration());
+        if (base.attribute(QStringLiteral("type")).contains(QLatin1String("audio"))) {
+            // Alwasy produces audio
+            m_audioCondition.insert(QStringLiteral("audio"), {});
+        } else {
+            // Check if this generator can provide audio
+            QDomNodeList params = base.elementsByTagName(QStringLiteral("parameter"));
+            for (int i = 0; i < params.count(); ++i) {
+                QDomElement currentParameter = params.item(i).toElement();
+                if (currentParameter.hasAttribute(QLatin1String("audio"))) {
+                    const QString audioVals = currentParameter.attribute(QStringLiteral("audio"));
+                    QStringList audioValsList;
+                    if (audioVals.contains(QLatin1Char(';'))) {
+                        audioValsList = audioVals.split(QLatin1Char(';'), Qt::SkipEmptyParts);
+                    } else {
+                        audioValsList = {audioVals};
+                    }
+                    m_audioCondition.insert(currentParameter.attribute(QStringLiteral("name")), audioValsList);
+                }
+            }
+        }
     }
 }
 
@@ -173,9 +193,15 @@ QUrl Generators::getSavedClip(QString clipFolder)
 
     if (url.isValid()) {
         Mlt::Tractor trac(pCore->getProjectProfile());
+        Mlt::Playlist playlist(pCore->getProjectProfile());
         m_producer->set("length", m_timePos->getValue());
         m_producer->set_in_and_out(0, m_timePos->getValue() - 1);
-        trac.set_track(*m_producer, 0);
+        playlist.append(*m_producer);
+        trac.set_track(playlist, 0);
+        if (!hasAudio()) {
+            Mlt::Producer trackProducer(trac.track(0));
+            trackProducer.set("hide", 2);
+        }
         QReadLocker lock(&pCore->xmlMutex);
         Mlt::Consumer c(pCore->getProjectProfile(), "xml", url.toLocalFile().toUtf8().constData());
         c.connect(trac);
@@ -184,3 +210,19 @@ QUrl Generators::getSavedClip(QString clipFolder)
     }
     return QUrl();
 }
+
+bool Generators::hasAudio() const
+{
+    if (m_audioCondition.isEmpty()) {
+        return false;
+    }
+    const QStringList paramCondition = m_audioCondition.value(m_audioCondition.firstKey());
+    if (paramCondition.isEmpty()) {
+        return true;
+    }
+    const QString paramVal = m_producer->get(m_audioCondition.firstKey().toUtf8().constData());
+    if (paramCondition.contains(paramVal)) {
+        return true;
+    }
+    return false;
+}

src/bin/generators/generators.h

@@ -47,6 +47,8 @@ private:
     std::shared_ptr<AssetParameterModel> m_assetModel;
     QLabel *m_preview;
     QPixmap m_pixmap;
+    QMap<QString, QStringList> m_audioCondition;
+    bool hasAudio() const;
 
 private Q_SLOTS:
     void updateProducer();