gsttools: use nullptr instead of NULL

Change-Id: I3b9b75b9f55bbb13bd5751a49b072102af675c4f
Reviewed-by: VaL Doroshchuk <valentyn.doroshchuk@qt.io>

12 files changed, 144 insertions, 144 deletions

diff --git a/src/gsttools/gstvideoconnector.c b/src/gsttools/gstvideoconnector.c
index b85f5bdbe..7f88a89af 100644
--- a/src/gsttools/gstvideoconnector.c
+++ b/src/gsttools/gstvideoconnector.c
@@ -116,13 +116,13 @@ gst_video_connector_class_init (GstVideoConnectorClass * klass)
     gst_video_connector_signals[SIGNAL_RESEND_NEW_SEGMENT] =
             g_signal_new ("resend-new-segment", G_TYPE_FROM_CLASS (klass),
                           G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
-                          G_STRUCT_OFFSET (GstVideoConnectorClass, resend_new_segment), NULL, NULL,
+                          G_STRUCT_OFFSET (GstVideoConnectorClass, resend_new_segment), nullptr, nullptr,
                           g_cclosure_marshal_VOID__BOOLEAN, G_TYPE_NONE, 1, G_TYPE_BOOLEAN);
 
     gst_video_connector_signals[SIGNAL_CONNECTION_FAILED] =
             g_signal_new ("connection-failed", G_TYPE_FROM_CLASS (klass),
                           G_SIGNAL_RUN_LAST,
-                          0, NULL, NULL,
+                          0, nullptr, nullptr,
                           g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
 }
 
@@ -159,7 +159,7 @@ gst_video_connector_init (GstVideoConnector *element,
     element->relinked = FALSE;
     element->failedSignalEmited = FALSE;
     gst_segment_init (&element->segment, GST_FORMAT_TIME);
-    element->latest_buffer = NULL;
+    element->latest_buffer = nullptr;
 }
 
 static void
@@ -167,9 +167,9 @@ gst_video_connector_reset (GstVideoConnector * element)
 {
     element->relinked = FALSE;
     element->failedSignalEmited = FALSE;
-    if (element->latest_buffer != NULL) {
+    if (element->latest_buffer != nullptr) {
         gst_buffer_unref (element->latest_buffer);
-        element->latest_buffer = NULL;
+        element->latest_buffer = nullptr;
     }
     gst_segment_init (&element->segment, GST_FORMAT_UNDEFINED);
 }
@@ -196,7 +196,7 @@ gst_video_connector_buffer_alloc (GstPad * pad, guint64 offset, guint size,
 
     if (!buf)
         return GST_FLOW_ERROR;
-    *buf = NULL;
+    *buf = nullptr;
 
     gboolean isFailed = FALSE;
     while (1) {
@@ -265,7 +265,7 @@ gst_video_connector_setcaps (GstPad  *pad, GstCaps *caps)
     /* forward-negotiate */
     gboolean res = gst_pad_set_caps(element->srcpad, caps);
 
-    gchar * debugmsg = NULL;
+    gchar * debugmsg = nullptr;
     GST_DEBUG_OBJECT(element, "gst_video_connector_setcaps %s %i", debugmsg = gst_caps_to_string(caps), res);
     if (debugmsg)
         g_free(debugmsg);
@@ -407,7 +407,7 @@ gst_video_connector_chain (GstPad * pad, GstBuffer * buf)
 
     if (element->latest_buffer) {
         gst_buffer_unref (element->latest_buffer);
-        element->latest_buffer = NULL;
+        element->latest_buffer = nullptr;
     }
 
     element->latest_buffer = gst_buffer_ref(buf);
diff --git a/src/gsttools/qgstappsrc.cpp b/src/gsttools/qgstappsrc.cpp
index d5c44ec08..f6ecd48be 100644
--- a/src/gsttools/qgstappsrc.cpp
+++ b/src/gsttools/qgstappsrc.cpp
@@ -69,7 +69,7 @@ bool QGstAppSrc::setup(GstElement* appsrc)
     gst_object_ref(G_OBJECT(m_appSrc));
     gst_app_src_set_callbacks(m_appSrc, (GstAppSrcCallbacks*)&m_callbacks, this, (GDestroyNotify)&QGstAppSrc::destroy_notify);
 
-    g_object_get(G_OBJECT(m_appSrc), "max-bytes", &m_maxBytes, NULL);
+    g_object_get(G_OBJECT(m_appSrc), "max-bytes", &m_maxBytes, nullptr);
 
     if (m_sequential)
         m_streamType = GST_APP_STREAM_TYPE_STREAM;
diff --git a/src/gsttools/qgstbufferpoolinterface_p.h b/src/gsttools/qgstbufferpoolinterface_p.h
index 45e573262..f5cbc35aa 100644
--- a/src/gsttools/qgstbufferpoolinterface_p.h
+++ b/src/gsttools/qgstbufferpoolinterface_p.h
@@ -79,7 +79,7 @@ public:
 
     /*!
       Build an QAbstractVideoBuffer instance from GstBuffer.
-      Returns NULL if GstBuffer is not compatible with this buffer pool.
+      Returns nullptr if GstBuffer is not compatible with this buffer pool.
 
       This method is called from gstreamer video sink thread.
      */
@@ -105,7 +105,7 @@ public:
 
     /*!
       Build an QAbstractVideoBuffer instance from compatible GstBuffer.
-      Returns NULL if GstBuffer is not compatible with this buffer pool.
+      Returns nullptr if GstBuffer is not compatible with this buffer pool.
 
       This method is called from gstreamer video sink thread.
      */
diff --git a/src/gsttools/qgstcodecsinfo.cpp b/src/gsttools/qgstcodecsinfo.cpp
index c6e61f824..2522ee19c 100644
--- a/src/gsttools/qgstcodecsinfo.cpp
+++ b/src/gsttools/qgstcodecsinfo.cpp
@@ -99,7 +99,7 @@ QStringList QGstCodecsInfo::codecOptions(const QString &codec) const
     if (elementName.isEmpty())
         return options;
 
-    GstElement *element = gst_element_factory_make(elementName, NULL);
+    GstElement *element = gst_element_factory_make(elementName, nullptr);
     if (element) {
         guint numProperties;
         GParamSpec **properties = g_object_class_list_properties(G_OBJECT_GET_CLASS(element),
@@ -174,7 +174,7 @@ void QGstCodecsInfo::updateCodecs(ElementType elementType)
                         }
                     }
 
-                    GstCaps *newCaps = gst_caps_new_full(newStructure, NULL);
+                    GstCaps *newCaps = gst_caps_new_full(newStructure, nullptr);
 
                     gchar *capsString = gst_caps_to_string(newCaps);
                     QString codec = QLatin1String(capsString);
diff --git a/src/gsttools/qgstreameraudioinputselector.cpp b/src/gsttools/qgstreameraudioinputselector.cpp
index 72d079cbc..36b36dda4 100644
--- a/src/gsttools/qgstreameraudioinputselector.cpp
+++ b/src/gsttools/qgstreameraudioinputselector.cpp
@@ -124,23 +124,23 @@ void QGstreamerAudioInputSelector::updateAlsaDevices()
     }
     n = hints;
 
-    while (*n != NULL) {
+    while (*n != nullptr) {
         char *name = snd_device_name_get_hint(*n, "NAME");
         char *descr = snd_device_name_get_hint(*n, "DESC");
         char *io = snd_device_name_get_hint(*n, "IOID");
 
-        if ((name != NULL) && (descr != NULL)) {
-            if ( io == NULL || qstrcmp(io,"Input") == 0 ) {
+        if ((name != nullptr) && (descr != nullptr)) {
+            if (io == nullptr || qstrcmp(io, "Input") == 0) {
                 m_names.append(QLatin1String("alsa:")+QString::fromUtf8(name));
                 m_descriptions.append(QString::fromUtf8(descr));
             }
         }
 
-        if (name != NULL)
+        if (name != nullptr)
             free(name);
-        if (descr != NULL)
+        if (descr != nullptr)
             free(descr);
-        if (io != NULL)
+        if (io != nullptr)
             free(io);
         n++;
     }
diff --git a/src/gsttools/qgstreamerbufferprobe.cpp b/src/gsttools/qgstreamerbufferprobe.cpp
index d95de4c63..e2956eadd 100644
--- a/src/gsttools/qgstreamerbufferprobe.cpp
+++ b/src/gsttools/qgstreamerbufferprobe.cpp
@@ -70,11 +70,11 @@ void QGstreamerBufferProbe::addProbeToPad(GstPad *pad, bool downstream)
                         : GST_PAD_PROBE_TYPE_EVENT_UPSTREAM,
                     capsProbe,
                     this,
-                    NULL);
+                    nullptr);
     }
     if (m_flags & ProbeBuffers) {
         m_bufferProbeId = gst_pad_add_probe(
-                    pad, GST_PAD_PROBE_TYPE_BUFFER, bufferProbe, this, NULL);
+                    pad, GST_PAD_PROBE_TYPE_BUFFER, bufferProbe, this, nullptr);
     }
 #else
     Q_UNUSED(downstream);
diff --git a/src/gsttools/qgstreamerbushelper.cpp b/src/gsttools/qgstreamerbushelper.cpp
index b2017aed9..1a4034eee 100644
--- a/src/gsttools/qgstreamerbushelper.cpp
+++ b/src/gsttools/qgstreamerbushelper.cpp
@@ -69,7 +69,7 @@ public:
             connect(m_intervalTimer, SIGNAL(timeout()), SLOT(interval()));
             m_intervalTimer->start();
         } else {
-            m_tag = gst_bus_add_watch_full(bus, G_PRIORITY_DEFAULT, busCallback, this, NULL);
+            m_tag = gst_bus_add_watch_full(bus, G_PRIORITY_DEFAULT, busCallback, this, nullptr);
         }
     }
 
diff --git a/src/gsttools/qgstreamerplayersession.cpp b/src/gsttools/qgstreamerplayersession.cpp
index 19b90a4d3..1d16df5b7 100644
--- a/src/gsttools/qgstreamerplayersession.cpp
+++ b/src/gsttools/qgstreamerplayersession.cpp
@@ -118,7 +118,7 @@ QGstreamerPlayerSession::QGstreamerPlayerSession(QObject *parent)
 
 void QGstreamerPlayerSession::initPlaybin()
 {
-    m_playbin = gst_element_factory_make(QT_GSTREAMER_PLAYBIN_ELEMENT_NAME, NULL);
+    m_playbin = gst_element_factory_make(QT_GSTREAMER_PLAYBIN_ELEMENT_NAME, nullptr);
     if (m_playbin) {
         //GST_PLAY_FLAG_NATIVE_VIDEO omits configuration of ffmpegcolorspace and videoscale,
         //since those elements are included in the video output bin when necessary.
@@ -131,7 +131,7 @@ void QGstreamerPlayerSession::initPlaybin()
             flags |= GST_PLAY_FLAG_NATIVE_VIDEO;
 #endif
         }
-        g_object_set(G_OBJECT(m_playbin), "flags", flags, NULL);
+        g_object_set(G_OBJECT(m_playbin), "flags", flags, nullptr);
 
         const QByteArray envAudioSink = qgetenv("QT_GSTREAMER_PLAYBIN_AUDIOSINK");
         GstElement *audioSink = gst_element_factory_make(envAudioSink.isEmpty() ? "autoaudiosink" : envAudioSink, "audiosink");
@@ -144,7 +144,7 @@ void QGstreamerPlayerSession::initPlaybin()
                 if (m_volumeElement) {
                     m_audioSink = gst_bin_new("audio-output-bin");
 
-                    gst_bin_add_many(GST_BIN(m_audioSink), m_volumeElement, audioSink, NULL);
+                    gst_bin_add_many(GST_BIN(m_audioSink), m_volumeElement, audioSink, nullptr);
                     gst_element_link(m_volumeElement, audioSink);
 
                     GstPad *pad = gst_element_get_static_pad(m_volumeElement, "sink");
@@ -156,13 +156,13 @@ void QGstreamerPlayerSession::initPlaybin()
                 }
             }
 
-            g_object_set(G_OBJECT(m_playbin), "audio-sink", m_audioSink, NULL);
+            g_object_set(G_OBJECT(m_playbin), "audio-sink", m_audioSink, nullptr);
             addAudioBufferProbe();
         }
     }
 
 #if GST_CHECK_VERSION(1,0,0)
-    m_videoIdentity = gst_element_factory_make("identity", NULL); // floating ref
+    m_videoIdentity = gst_element_factory_make("identity", nullptr); // floating ref
 #else
     m_videoIdentity = GST_ELEMENT(g_object_new(gst_video_connector_get_type(), 0)); // floating ref
     g_signal_connect(G_OBJECT(m_videoIdentity), "connection-failed", G_CALLBACK(insertColorSpaceElement), (gpointer)this);
@@ -172,8 +172,8 @@ void QGstreamerPlayerSession::initPlaybin()
     qt_gst_object_ref_sink(GST_OBJECT(m_colorSpace));
 #endif
 
-    m_nullVideoSink = gst_element_factory_make("fakesink", NULL);
-    g_object_set(G_OBJECT(m_nullVideoSink), "sync", true, NULL);
+    m_nullVideoSink = gst_element_factory_make("fakesink", nullptr);
+    g_object_set(G_OBJECT(m_nullVideoSink), "sync", true, nullptr);
     gst_object_ref(GST_OBJECT(m_nullVideoSink));
 
     m_videoOutputBin = gst_bin_new("video-output-bin");
@@ -183,15 +183,15 @@ void QGstreamerPlayerSession::initPlaybin()
     GstElement *videoOutputSink = m_videoIdentity;
 #if QT_CONFIG(gstreamer_gl)
     if (QGstUtils::useOpenGL()) {
-        videoOutputSink = gst_element_factory_make("glupload", NULL);
-        GstElement *colorConvert = gst_element_factory_make("glcolorconvert", NULL);
-        gst_bin_add_many(GST_BIN(m_videoOutputBin), videoOutputSink, colorConvert, m_videoIdentity, m_nullVideoSink, NULL);
-        gst_element_link_many(videoOutputSink, colorConvert, m_videoIdentity, NULL);
+        videoOutputSink = gst_element_factory_make("glupload", nullptr);
+        GstElement *colorConvert = gst_element_factory_make("glcolorconvert", nullptr);
+        gst_bin_add_many(GST_BIN(m_videoOutputBin), videoOutputSink, colorConvert, m_videoIdentity, m_nullVideoSink, nullptr);
+        gst_element_link_many(videoOutputSink, colorConvert, m_videoIdentity, nullptr);
     } else {
-        gst_bin_add_many(GST_BIN(m_videoOutputBin), m_videoIdentity, m_nullVideoSink, NULL);
+        gst_bin_add_many(GST_BIN(m_videoOutputBin), m_videoIdentity, m_nullVideoSink, nullptr);
     }
 #else
-    gst_bin_add_many(GST_BIN(m_videoOutputBin), m_videoIdentity, m_nullVideoSink, NULL);
+    gst_bin_add_many(GST_BIN(m_videoOutputBin), m_videoIdentity, m_nullVideoSink, nullptr);
 #endif
     gst_element_link(m_videoIdentity, m_nullVideoSink);
 
@@ -206,7 +206,7 @@ void QGstreamerPlayerSession::initPlaybin()
         // Sort out messages
         setBus(gst_element_get_bus(m_playbin));
 
-        g_object_set(G_OBJECT(m_playbin), "video-sink", m_videoOutputBin, NULL);
+        g_object_set(G_OBJECT(m_playbin), "video-sink", m_videoOutputBin, nullptr);
 
         g_signal_connect(G_OBJECT(m_playbin), "notify::source", G_CALLBACK(playbinNotifySource), this);
         g_signal_connect(G_OBJECT(m_playbin), "element-added",  G_CALLBACK(handleElementAdded), this);
@@ -287,7 +287,7 @@ void QGstreamerPlayerSession::configureAppSrcElement(GObject* object, GObject *o
         return;
 
     GstElement *appsrc;
-    g_object_get(orig, "source", &appsrc, NULL);
+    g_object_get(orig, "source", &appsrc, nullptr);
 
     if (!self->appsrc()->setup(appsrc))
         qWarning()<<"Could not setup appsrc element";
@@ -314,7 +314,7 @@ void QGstreamerPlayerSession::loadFromStream(const QNetworkRequest &request, QIO
         m_tags.clear();
         emit tagsChanged();
 
-        g_object_set(G_OBJECT(m_playbin), "uri", "appsrc://", NULL);
+        g_object_set(G_OBJECT(m_playbin), "uri", "appsrc://", nullptr);
 
         if (!m_streamTypes.isEmpty()) {
             m_streamProperties.clear();
@@ -346,7 +346,7 @@ void QGstreamerPlayerSession::loadFromUri(const QNetworkRequest &request)
         m_tags.clear();
         emit tagsChanged();
 
-        g_object_set(G_OBJECT(m_playbin), "uri", m_request.url().toEncoded().constData(), NULL);
+        g_object_set(G_OBJECT(m_playbin), "uri", m_request.url().toEncoded().constData(), nullptr);
 
         if (!m_streamTypes.isEmpty()) {
             m_streamProperties.clear();
@@ -547,13 +547,13 @@ int QGstreamerPlayerSession::activeStream(QMediaStreamsControl::StreamType strea
     if (m_playbin) {
         switch (streamType) {
         case QMediaStreamsControl::AudioStream:
-            g_object_get(G_OBJECT(m_playbin), "current-audio", &streamNumber, NULL);
+            g_object_get(G_OBJECT(m_playbin), "current-audio", &streamNumber, nullptr);
             break;
         case QMediaStreamsControl::VideoStream:
-            g_object_get(G_OBJECT(m_playbin), "current-video", &streamNumber, NULL);
+            g_object_get(G_OBJECT(m_playbin), "current-video", &streamNumber, nullptr);
             break;
         case QMediaStreamsControl::SubPictureStream:
-            g_object_get(G_OBJECT(m_playbin), "current-text", &streamNumber, NULL);
+            g_object_get(G_OBJECT(m_playbin), "current-text", &streamNumber, nullptr);
             break;
         default:
             break;
@@ -578,13 +578,13 @@ void QGstreamerPlayerSession::setActiveStream(QMediaStreamsControl::StreamType s
     if (m_playbin) {
         switch (streamType) {
         case QMediaStreamsControl::AudioStream:
-            g_object_set(G_OBJECT(m_playbin), "current-audio", streamNumber, NULL);
+            g_object_set(G_OBJECT(m_playbin), "current-audio", streamNumber, nullptr);
             break;
         case QMediaStreamsControl::VideoStream:
-            g_object_set(G_OBJECT(m_playbin), "current-video", streamNumber, NULL);
+            g_object_set(G_OBJECT(m_playbin), "current-video", streamNumber, nullptr);
             break;
         case QMediaStreamsControl::SubPictureStream:
-            g_object_set(G_OBJECT(m_playbin), "current-text", streamNumber, NULL);
+            g_object_set(G_OBJECT(m_playbin), "current-text", streamNumber, nullptr);
             break;
         default:
             break;
@@ -735,7 +735,7 @@ void QGstreamerPlayerSession::setVideoRenderer(QObject *videoOutput)
             qDebug() << "Failed to connect video output, inserting the colorspace element.";
 #endif
             gst_bin_add(GST_BIN(m_videoOutputBin), m_colorSpace);
-            linked = gst_element_link_many(m_videoIdentity, m_colorSpace, m_videoSink, NULL);
+            linked = gst_element_link_many(m_videoIdentity, m_colorSpace, m_videoSink, nullptr);
         }
 #endif
 
@@ -744,7 +744,7 @@ void QGstreamerPlayerSession::setVideoRenderer(QObject *videoOutput)
 
         if (g_object_class_find_property(G_OBJECT_GET_CLASS(m_videoSink), "show-preroll-frame") != 0) {
             gboolean value = m_displayPrerolledFrame;
-            g_object_set(G_OBJECT(m_videoSink), "show-preroll-frame", value, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "show-preroll-frame", value, nullptr);
         }
 
         addVideoBufferProbe();
@@ -780,7 +780,7 @@ void QGstreamerPlayerSession::setVideoRenderer(QObject *videoOutput)
         //block pads, async to avoid locking in paused state
         GstPad *srcPad = gst_element_get_static_pad(m_videoIdentity, "src");
 #if GST_CHECK_VERSION(1,0,0)
-        this->pad_probe_id = gst_pad_add_probe(srcPad, (GstPadProbeType)(GST_PAD_PROBE_TYPE_BUFFER | GST_PAD_PROBE_TYPE_BLOCKING), block_pad_cb, this, NULL);
+        this->pad_probe_id = gst_pad_add_probe(srcPad, (GstPadProbeType)(GST_PAD_PROBE_TYPE_BUFFER | GST_PAD_PROBE_TYPE_BLOCKING), block_pad_cb, this, nullptr);
 #else
         gst_pad_set_blocked_async(srcPad, true, &block_pad_cb, this);
 #endif
@@ -813,7 +813,7 @@ void QGstreamerPlayerSession::finishVideoOutputChange()
         //pad is not blocked, it's possible to swap outputs only in the null state
         qWarning() << "Pad is not blocked yet, could not switch video sink";
         GstState identityElementState = GST_STATE_NULL;
-        gst_element_get_state(m_videoIdentity, &identityElementState, NULL, GST_CLOCK_TIME_NONE);
+        gst_element_get_state(m_videoIdentity, &identityElementState, nullptr, GST_CLOCK_TIME_NONE);
         if (identityElementState != GST_STATE_NULL) {
             gst_object_unref(GST_OBJECT(srcPad));
             return; //can't change vo yet, received async call from the previous change
@@ -871,7 +871,7 @@ void QGstreamerPlayerSession::finishVideoOutputChange()
         qDebug() << "Failed to connect video output, inserting the colorspace element.";
 #endif
         gst_bin_add(GST_BIN(m_videoOutputBin), m_colorSpace);
-        linked = gst_element_link_many(m_videoIdentity, m_colorSpace, m_videoSink, NULL);
+        linked = gst_element_link_many(m_videoIdentity, m_colorSpace, m_videoSink, nullptr);
     }
 #endif
 
@@ -962,7 +962,7 @@ void QGstreamerPlayerSession::insertColorSpaceElement(GstElement *element, gpoin
 
     gst_element_unlink(session->m_videoIdentity, session->m_videoSink);
     gst_bin_add(GST_BIN(session->m_videoOutputBin), session->m_colorSpace);
-    gst_element_link_many(session->m_videoIdentity, session->m_colorSpace, session->m_videoSink, NULL);
+    gst_element_link_many(session->m_videoIdentity, session->m_colorSpace, session->m_videoSink, nullptr);
 
     GstState state = GST_STATE_VOID_PENDING;
 
@@ -1106,7 +1106,7 @@ void QGstreamerPlayerSession::setVolume(int volume)
         m_volume = volume;
 
         if (m_volumeElement)
-            g_object_set(G_OBJECT(m_volumeElement), "volume", m_volume / 100.0, NULL);
+            g_object_set(G_OBJECT(m_volumeElement), "volume", m_volume / 100.0, nullptr);
 
         emit volumeChanged(m_volume);
     }
@@ -1121,7 +1121,7 @@ void QGstreamerPlayerSession::setMuted(bool muted)
         m_muted = muted;
 
         if (m_volumeElement)
-            g_object_set(G_OBJECT(m_volumeElement), "mute", m_muted ? TRUE : FALSE, NULL);
+            g_object_set(G_OBJECT(m_volumeElement), "mute", m_muted ? TRUE : FALSE, nullptr);
 
         emit mutedStateChanged(m_muted);
     }
@@ -1453,9 +1453,9 @@ void QGstreamerPlayerSession::getStreamsInfo()
     gint videoStreamsCount = 0;
     gint textStreamsCount = 0;
 
-    g_object_get(G_OBJECT(m_playbin), "n-audio", &audioStreamsCount, NULL);
-    g_object_get(G_OBJECT(m_playbin), "n-video", &videoStreamsCount, NULL);
-    g_object_get(G_OBJECT(m_playbin), "n-text", &textStreamsCount, NULL);
+    g_object_get(G_OBJECT(m_playbin), "n-audio", &audioStreamsCount, nullptr);
+    g_object_get(G_OBJECT(m_playbin), "n-video", &videoStreamsCount, nullptr);
+    g_object_get(G_OBJECT(m_playbin), "n-text", &textStreamsCount, nullptr);
 
     haveAudio = audioStreamsCount > 0;
     haveVideo = videoStreamsCount > 0;
@@ -1615,7 +1615,7 @@ void QGstreamerPlayerSession::playbinNotifySource(GObject *o, GParamSpec *p, gpo
     Q_UNUSED(p);
 
     GstElement *source = 0;
-    g_object_get(o, "source", &source, NULL);
+    g_object_get(o, "source", &source, nullptr);
     if (source == 0)
         return;
 
@@ -1632,7 +1632,7 @@ void QGstreamerPlayerSession::playbinNotifySource(GObject *o, GParamSpec *p, gpo
     // defined in extra-headers
     if (g_object_class_find_property(G_OBJECT_GET_CLASS(source), "user-agent") != 0) {
         g_object_set(G_OBJECT(source), "user-agent",
-                     self->m_request.rawHeader(userAgentString).constData(), NULL);
+                     self->m_request.rawHeader(userAgentString).constData(), nullptr);
     }
 
     // The rest
@@ -1657,7 +1657,7 @@ void QGstreamerPlayerSession::playbinNotifySource(GObject *o, GParamSpec *p, gpo
         }
 
         if (gst_structure_n_fields(extras) > 0)
-            g_object_set(G_OBJECT(source), "extra-headers", extras, NULL);
+            g_object_set(G_OBJECT(source), "extra-headers", extras, nullptr);
 
         gst_structure_free(extras);
     }
@@ -1673,7 +1673,7 @@ void QGstreamerPlayerSession::playbinNotifySource(GObject *o, GParamSpec *p, gpo
         // Gst 0.10 -> microsecond
         convertedTimeout *= 1000000;
 #endif
-        g_object_set(G_OBJECT(source), "timeout", convertedTimeout, NULL);
+        g_object_set(G_OBJECT(source), "timeout", convertedTimeout, nullptr);
         self->m_sourceType = UDPSrc;
         //The udpsrc is always a live source.
         self->m_isLiveSource = true;
@@ -1682,26 +1682,26 @@ void QGstreamerPlayerSession::playbinNotifySource(GObject *o, GParamSpec *p, gpo
         const QString var = QLatin1String("udpsrc.caps");
         if (query.hasQueryItem(var)) {
             GstCaps *caps = gst_caps_from_string(query.queryItemValue(var).toLatin1().constData());
-            g_object_set(G_OBJECT(source), "caps", caps, NULL);
+            g_object_set(G_OBJECT(source), "caps", caps, nullptr);
             gst_caps_unref(caps);
         }
     } else if (qstrcmp(G_OBJECT_CLASS_NAME(G_OBJECT_GET_CLASS(source)), "GstSoupHTTPSrc") == 0) {
         //souphttpsrc timeout unit = second
-        g_object_set(G_OBJECT(source), "timeout", guint(timeout), NULL);
+        g_object_set(G_OBJECT(source), "timeout", guint(timeout), nullptr);
         self->m_sourceType = SoupHTTPSrc;
         //since gst_base_src_is_live is not reliable, so we check the source property directly
         gboolean isLive = false;
-        g_object_get(G_OBJECT(source), "is-live", &isLive, NULL);
+        g_object_get(G_OBJECT(source), "is-live", &isLive, nullptr);
         self->m_isLiveSource = isLive;
     } else if (qstrcmp(G_OBJECT_CLASS_NAME(G_OBJECT_GET_CLASS(source)), "GstMMSSrc") == 0) {
         self->m_sourceType = MMSSrc;
         self->m_isLiveSource = gst_base_src_is_live(GST_BASE_SRC(source));
-        g_object_set(G_OBJECT(source), "tcp-timeout", G_GUINT64_CONSTANT(timeout*1000000), NULL);
+        g_object_set(G_OBJECT(source), "tcp-timeout", G_GUINT64_CONSTANT(timeout*1000000), nullptr);
     } else if (qstrcmp(G_OBJECT_CLASS_NAME(G_OBJECT_GET_CLASS(source)), "GstRTSPSrc") == 0) {
         //rtspsrc acts like a live source and will therefore only generate data in the PLAYING state.
         self->m_sourceType = RTSPSrc;
         self->m_isLiveSource = true;
-        g_object_set(G_OBJECT(source), "buffer-mode", 1, NULL);
+        g_object_set(G_OBJECT(source), "buffer-mode", 1, nullptr);
     } else {
         self->m_sourceType = UnknownSrc;
         self->m_isLiveSource = gst_base_src_is_live(GST_BASE_SRC(source));
@@ -1715,7 +1715,7 @@ void QGstreamerPlayerSession::playbinNotifySource(GObject *o, GParamSpec *p, gpo
 #endif
 
     if (self->m_videoSink)
-        g_object_set(G_OBJECT(self->m_videoSink), "sync", !self->m_isLiveSource, NULL);
+        g_object_set(G_OBJECT(self->m_videoSink), "sync", !self->m_isLiveSource, nullptr);
 
     gst_object_unref(source);
 }
@@ -1736,7 +1736,7 @@ void QGstreamerPlayerSession::handleVolumeChange(GObject *o, GParamSpec *p, gpoi
 void QGstreamerPlayerSession::updateVolume()
 {
     double volume = 1.0;
-    g_object_get(m_playbin, "volume", &volume, NULL);
+    g_object_get(m_playbin, "volume", &volume, nullptr);
 
     if (m_volume != int(volume*100 + 0.5)) {
         m_volume = int(volume*100 + 0.5);
@@ -1758,7 +1758,7 @@ void QGstreamerPlayerSession::handleMutedChange(GObject *o, GParamSpec *p, gpoin
 void QGstreamerPlayerSession::updateMuted()
 {
     gboolean muted = FALSE;
-    g_object_get(G_OBJECT(m_playbin), "mute", &muted, NULL);
+    g_object_get(G_OBJECT(m_playbin), "mute", &muted, nullptr);
     if (m_muted != muted) {
         m_muted = muted;
 #ifdef DEBUG_PLAYBIN
@@ -1773,8 +1773,8 @@ static gboolean factory_can_src_any_caps (GstElementFactory *factory, const GstC
 {
     GList *templates;
 
-    g_return_val_if_fail(factory != NULL, FALSE);
-    g_return_val_if_fail(caps != NULL, FALSE);
+    g_return_val_if_fail(factory != nullptr, FALSE);
+    g_return_val_if_fail(caps != nullptr, FALSE);
 
     templates = factory->staticpadtemplates;
 
@@ -1811,7 +1811,7 @@ GstAutoplugSelectResult QGstreamerPlayerSession::handleAutoplugSelect(GstBin *bi
     if (g_str_has_prefix(factoryName, "vaapi")) {
         GstPad *sinkPad = gst_element_get_static_pad(session->m_videoSink, "sink");
 #if GST_CHECK_VERSION(1,0,0)
-        GstCaps *sinkCaps = gst_pad_query_caps(sinkPad, NULL);
+        GstCaps *sinkCaps = gst_pad_query_caps(sinkPad, nullptr);
 #else
         GstCaps *sinkCaps = gst_pad_get_caps(sinkPad);
 #endif
@@ -1841,7 +1841,7 @@ void QGstreamerPlayerSession::handleElementAdded(GstBin *bin, GstElement *elemen
 
     if (g_str_has_prefix(elementName, "queue2")) {
         // Disable on-disk buffering.
-        g_object_set(G_OBJECT(element), "temp-template", NULL, NULL);
+        g_object_set(G_OBJECT(element), "temp-template", nullptr, nullptr);
     } else if (g_str_has_prefix(elementName, "uridecodebin") ||
 #if GST_CHECK_VERSION(1,0,0)
         g_str_has_prefix(elementName, "decodebin")) {
@@ -1849,7 +1849,7 @@ void QGstreamerPlayerSession::handleElementAdded(GstBin *bin, GstElement *elemen
         g_str_has_prefix(elementName, "decodebin2")) {
         if (g_str_has_prefix(elementName, "uridecodebin")) {
             // Add video/x-surface (VAAPI) to default raw formats
-            g_object_set(G_OBJECT(element), "caps", gst_static_caps_get(&static_RawCaps), NULL);
+            g_object_set(G_OBJECT(element), "caps", gst_static_caps_get(&static_RawCaps), nullptr);
             // listen for uridecodebin autoplug-select to skip VAAPI usage when the current
             // video sink doesn't support it
             g_signal_connect(element, "autoplug-select", G_CALLBACK(handleAutoplugSelect), session);
@@ -1892,7 +1892,7 @@ void QGstreamerPlayerSession::showPrerollFrames(bool enabled)
             g_object_class_find_property(G_OBJECT_GET_CLASS(m_videoSink), "show-preroll-frame") != 0) {
 
         gboolean value = enabled;
-        g_object_set(G_OBJECT(m_videoSink), "show-preroll-frame", value, NULL);
+        g_object_set(G_OBJECT(m_videoSink), "show-preroll-frame", value, nullptr);
         m_displayPrerolledFrame = enabled;
     }
 }
diff --git a/src/gsttools/qgstreamervideooverlay.cpp b/src/gsttools/qgstreamervideooverlay.cpp
index 6b862e475..d410be7d9 100644
--- a/src/gsttools/qgstreamervideooverlay.cpp
+++ b/src/gsttools/qgstreamervideooverlay.cpp
@@ -122,7 +122,7 @@ public:
     {
         int brightness = 0;
         if (m_hasBrightness)
-            g_object_get(G_OBJECT(m_videoSink), "brightness", &brightness, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "brightness", &brightness, nullptr);
 
         return brightness / 10;
     }
@@ -131,7 +131,7 @@ public:
     {
         m_brightness = brightness;
         if (m_hasBrightness)
-            g_object_set(G_OBJECT(m_videoSink), "brightness", brightness * 10, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "brightness", brightness * 10, nullptr);
 
         return m_hasBrightness;
     }
@@ -140,7 +140,7 @@ public:
     {
         int contrast = 0;
         if (m_hasContrast)
-            g_object_get(G_OBJECT(m_videoSink), "contrast", &contrast, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "contrast", &contrast, nullptr);
 
         return contrast / 10;
     }
@@ -149,7 +149,7 @@ public:
     {
         m_contrast = contrast;
         if (m_hasContrast)
-            g_object_set(G_OBJECT(m_videoSink), "contrast", contrast * 10, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "contrast", contrast * 10, nullptr);
 
         return m_hasContrast;
     }
@@ -158,7 +158,7 @@ public:
     {
         int hue = 0;
         if (m_hasHue)
-            g_object_get(G_OBJECT(m_videoSink), "hue", &hue, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "hue", &hue, nullptr);
 
         return hue / 10;
     }
@@ -167,7 +167,7 @@ public:
     {
         m_hue = hue;
         if (m_hasHue)
-            g_object_set(G_OBJECT(m_videoSink), "hue", hue * 10, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "hue", hue * 10, nullptr);
 
         return m_hasHue;
     }
@@ -176,7 +176,7 @@ public:
     {
         int saturation = 0;
         if (m_hasSaturation)
-            g_object_get(G_OBJECT(m_videoSink), "saturation", &saturation, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "saturation", &saturation, nullptr);
 
         return saturation / 10;
     }
@@ -185,7 +185,7 @@ public:
     {
         m_saturation = saturation;
         if (m_hasSaturation)
-            g_object_set(G_OBJECT(m_videoSink), "saturation", saturation * 10, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "saturation", saturation * 10, nullptr);
 
         return m_hasSaturation;
     }
@@ -195,7 +195,7 @@ public:
         Qt::AspectRatioMode mode = Qt::KeepAspectRatio;
         if (m_hasForceAspectRatio) {
             gboolean forceAR = false;
-            g_object_get(G_OBJECT(m_videoSink), "force-aspect-ratio", &forceAR, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "force-aspect-ratio", &forceAR, nullptr);
             if (!forceAR)
                 mode = Qt::IgnoreAspectRatio;
         }
@@ -210,7 +210,7 @@ public:
             g_object_set(G_OBJECT(m_videoSink),
                          "force-aspect-ratio",
                          (mode == Qt::KeepAspectRatio),
-                         (const char*)NULL);
+                         nullptr);
         }
     }
 
@@ -245,7 +245,7 @@ public:
     {
         gfloat brightness = 0;
         if (m_hasBrightness)
-            g_object_get(G_OBJECT(m_videoSink), "brightness", &brightness, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "brightness", &brightness, nullptr);
 
         return brightness * 100; // [-1,1] -> [-100,100]
     }
@@ -255,7 +255,7 @@ public:
         m_brightness = brightness;
         if (m_hasBrightness) {
             gfloat v = brightness / 100.0; // [-100,100] -> [-1,1]
-            g_object_set(G_OBJECT(m_videoSink), "brightness", v, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "brightness", v, nullptr);
         }
 
         return m_hasBrightness;
@@ -265,7 +265,7 @@ public:
     {
         gfloat contrast = 1;
         if (m_hasContrast)
-            g_object_get(G_OBJECT(m_videoSink), "contrast", &contrast, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "contrast", &contrast, nullptr);
 
         return (contrast - 1) * 100; // [0,2] -> [-100,100]
     }
@@ -275,7 +275,7 @@ public:
         m_contrast = contrast;
         if (m_hasContrast) {
             gfloat v = (contrast / 100.0) + 1; // [-100,100] -> [0,2]
-            g_object_set(G_OBJECT(m_videoSink), "contrast", v, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "contrast", v, nullptr);
         }
 
         return m_hasContrast;
@@ -285,7 +285,7 @@ public:
     {
         gfloat hue = 0;
         if (m_hasHue)
-            g_object_get(G_OBJECT(m_videoSink), "hue", &hue, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "hue", &hue, nullptr);
 
         return hue / 180 * 100; // [-180,180] -> [-100,100]
     }
@@ -295,7 +295,7 @@ public:
         m_hue = hue;
         if (m_hasHue) {
             gfloat v = hue / 100.0 * 180; // [-100,100] -> [-180,180]
-            g_object_set(G_OBJECT(m_videoSink), "hue", v, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "hue", v, nullptr);
         }
 
         return m_hasHue;
@@ -305,7 +305,7 @@ public:
     {
         gfloat saturation = 1;
         if (m_hasSaturation)
-            g_object_get(G_OBJECT(m_videoSink), "saturation", &saturation, NULL);
+            g_object_get(G_OBJECT(m_videoSink), "saturation", &saturation, nullptr);
 
         return (saturation - 1) * 100; // [0,2] -> [-100,100]
     }
@@ -315,7 +315,7 @@ public:
         m_saturation = saturation;
         if (m_hasSaturation) {
             gfloat v = (saturation / 100.0) + 1; // [-100,100] -> [0,2]
-            g_object_set(G_OBJECT(m_videoSink), "saturation", v, NULL);
+            g_object_set(G_OBJECT(m_videoSink), "saturation", v, nullptr);
         }
 
         return m_hasSaturation;
@@ -350,7 +350,7 @@ static GstElement *findBestVideoSink()
             continue;
 #endif
         if (platform == QLatin1String(elementMap[i].qtPlatform)
-                && (choice = gst_element_factory_make(elementMap[i].gstreamerElement, NULL))) {
+                && (choice = gst_element_factory_make(elementMap[i].gstreamerElement, nullptr))) {
 
             if (qt_gst_element_is_functioning(choice))
                 return choice;
@@ -363,13 +363,13 @@ static GstElement *findBestVideoSink()
     // If none of the known video sinks are available, try to find one that implements the
     // GstVideoOverlay interface and has autoplugging rank.
     GList *list = qt_gst_video_sinks();
-    for (GList *item = list; item != NULL; item = item->next) {
+    for (GList *item = list; item != nullptr; item = item->next) {
         GstElementFactory *f = GST_ELEMENT_FACTORY(item->data);
 
         if (!gst_element_factory_has_interface(f, QT_GSTREAMER_VIDEOOVERLAY_INTERFACE_NAME))
             continue;
 
-        if (GstElement *el = gst_element_factory_create(f, NULL)) {
+        if (GstElement *el = gst_element_factory_create(f, nullptr)) {
             if (qt_gst_element_is_functioning(el)) {
                 choice = el;
                 break;
@@ -390,7 +390,7 @@ QGstreamerVideoOverlay::QGstreamerVideoOverlay(QObject *parent, const QByteArray
 {
     GstElement *sink = nullptr;
     if (!elementName.isEmpty())
-        sink = gst_element_factory_make(elementName.constData(), NULL);
+        sink = gst_element_factory_make(elementName.constData(), nullptr);
     else
         sink = findBestVideoSink();
 
@@ -567,7 +567,7 @@ void QGstreamerVideoOverlay::updateIsActive()
     gboolean showPreroll = true;
 
     if (m_sinkProperties->hasShowPrerollFrame())
-        g_object_get(G_OBJECT(m_videoSink), "show-preroll-frame", &showPreroll, NULL);
+        g_object_get(G_OBJECT(m_videoSink), "show-preroll-frame", &showPreroll, nullptr);
 
     bool newIsActive = (state == GST_STATE_PLAYING || (state == GST_STATE_PAUSED && showPreroll));
 
diff --git a/src/gsttools/qgstutils.cpp b/src/gsttools/qgstutils.cpp
index f8a9d79c1..f998c4309 100644
--- a/src/gsttools/qgstutils.cpp
+++ b/src/gsttools/qgstutils.cpp
@@ -424,7 +424,7 @@ GstCaps *QGstUtils::capsForAudioFormat(const QAudioFormat &format)
                     "format"  , G_TYPE_STRING, gst_audio_format_to_string(qt_audioLookup[i].format),
                     "rate"    , G_TYPE_INT   , format.sampleRate(),
                     "channels", G_TYPE_INT   , format.channelCount(),
-                    NULL);
+                    nullptr);
     }
     return 0;
 #else
@@ -432,29 +432,29 @@ GstCaps *QGstUtils::capsForAudioFormat(const QAudioFormat &format)
 
     if (format.isValid()) {
         if (format.sampleType() == QAudioFormat::SignedInt || format.sampleType() == QAudioFormat::UnSignedInt) {
-            structure = gst_structure_new("audio/x-raw-int", NULL);
+            structure = gst_structure_new("audio/x-raw-int", nullptr);
         } else if (format.sampleType() == QAudioFormat::Float) {
-            structure = gst_structure_new("audio/x-raw-float", NULL);
+            structure = gst_structure_new("audio/x-raw-float", nullptr);
         }
     }
 
     GstCaps *caps = 0;
 
     if (structure) {
-        gst_structure_set(structure, "rate", G_TYPE_INT, format.sampleRate(), NULL);
-        gst_structure_set(structure, "channels", G_TYPE_INT, format.channelCount(), NULL);
-        gst_structure_set(structure, "width", G_TYPE_INT, format.sampleSize(), NULL);
-        gst_structure_set(structure, "depth", G_TYPE_INT, format.sampleSize(), NULL);
+        gst_structure_set(structure, "rate", G_TYPE_INT, format.sampleRate(), nullptr);
+        gst_structure_set(structure, "channels", G_TYPE_INT, format.channelCount(), nullptr);
+        gst_structure_set(structure, "width", G_TYPE_INT, format.sampleSize(), nullptr);
+        gst_structure_set(structure, "depth", G_TYPE_INT, format.sampleSize(), nullptr);
 
         if (format.byteOrder() == QAudioFormat::LittleEndian)
-            gst_structure_set(structure, "endianness", G_TYPE_INT, 1234, NULL);
+            gst_structure_set(structure, "endianness", G_TYPE_INT, 1234, nullptr);
         else if (format.byteOrder() == QAudioFormat::BigEndian)
-            gst_structure_set(structure, "endianness", G_TYPE_INT, 4321, NULL);
+            gst_structure_set(structure, "endianness", G_TYPE_INT, 4321, nullptr);
 
         if (format.sampleType() == QAudioFormat::SignedInt)
-            gst_structure_set(structure, "signed", G_TYPE_BOOLEAN, TRUE, NULL);
+            gst_structure_set(structure, "signed", G_TYPE_BOOLEAN, TRUE, nullptr);
         else if (format.sampleType() == QAudioFormat::UnSignedInt)
-            gst_structure_set(structure, "signed", G_TYPE_BOOLEAN, FALSE, NULL);
+            gst_structure_set(structure, "signed", G_TYPE_BOOLEAN, FALSE, nullptr);
 
         caps = gst_caps_new_empty();
         Q_ASSERT(caps);
@@ -470,7 +470,7 @@ void QGstUtils::initializeGst()
     static bool initialized = false;
     if (!initialized) {
         initialized = true;
-        gst_init(NULL, NULL);
+        gst_init(nullptr, nullptr);
     }
 }
 
@@ -606,8 +606,8 @@ QVector<QGstUtils::CameraInfo> QGstUtils::enumerateCameras(GstElementFactory *fa
                         // no-op
                     } else for (int i = 0; i < 2; ++i) {
                         gint orientation = 0;
-                        g_object_set(G_OBJECT(camera), "camera-device", i, NULL);
-                        g_object_get(G_OBJECT(camera), "sensor-mount-angle", &orientation, NULL);
+                        g_object_set(G_OBJECT(camera), "camera-device", i, nullptr);
+                        g_object_get(G_OBJECT(camera), "sensor-mount-angle", &orientation, nullptr);
 
                         devices[i].orientation = (720 - orientation) % 360;
                     }
@@ -807,7 +807,7 @@ QSet<QString> QGstUtils::supportedMimeTypes(bool (*isValidFactory)(GstElementFac
     QSet<QString> supportedMimeTypes;
 
     //enumerate supported mime types
-    gst_init(NULL, NULL);
+    gst_init(nullptr, nullptr);
 
 #if GST_CHECK_VERSION(1,0,0)
     GstRegistry *registry = gst_registry_get();
@@ -829,7 +829,7 @@ QSet<QString> QGstUtils::supportedMimeTypes(bool (*isValidFactory)(GstElementFac
         GList *orig_features = gst_registry_get_feature_list_by_plugin(
                     registry, gst_plugin_get_name(plugin));
         for (GList *features = orig_features; features; features = g_list_next(features)) {
-            if (G_UNLIKELY(features->data == NULL))
+            if (G_UNLIKELY(features->data == nullptr))
                 continue;
 
             GstPluginFeature *feature = GST_PLUGIN_FEATURE(features->data);
@@ -1238,7 +1238,7 @@ GstCaps *QGstUtils::capsForFormats(const QList<QVideoFrame::PixelFormat> &format
             gst_caps_append_structure(caps, gst_structure_new(
                     "video/x-raw",
                     "format"   , G_TYPE_STRING, gst_video_format_to_string(qt_videoFormatLookup[index].gstFormat),
-                    NULL));
+                    nullptr));
         }
     }
 #else
@@ -1249,7 +1249,7 @@ GstCaps *QGstUtils::capsForFormats(const QList<QVideoFrame::PixelFormat> &format
             gst_caps_append_structure(caps, gst_structure_new(
                     "video/x-raw-yuv",
                     "format", GST_TYPE_FOURCC, qt_yuvColorLookup[index].fourcc,
-                    NULL));
+                    nullptr));
             continue;
         }
 
@@ -1265,11 +1265,11 @@ GstCaps *QGstUtils::capsForFormats(const QList<QVideoFrame::PixelFormat> &format
                         "red_mask"  , G_TYPE_INT, qt_rgbColorLookup[i].red,
                         "green_mask", G_TYPE_INT, qt_rgbColorLookup[i].green,
                         "blue_mask" , G_TYPE_INT, qt_rgbColorLookup[i].blue,
-                        NULL);
+                        nullptr);
 
                 if (qt_rgbColorLookup[i].alpha != 0) {
                     gst_structure_set(
-                            structure, "alpha_mask", G_TYPE_INT, qt_rgbColorLookup[i].alpha, NULL);
+                            structure, "alpha_mask", G_TYPE_INT, qt_rgbColorLookup[i].alpha, nullptr);
                 }
                 gst_caps_append_structure(caps, structure);
             }
@@ -1282,7 +1282,7 @@ GstCaps *QGstUtils::capsForFormats(const QList<QVideoFrame::PixelFormat> &format
                 "framerate", GST_TYPE_FRACTION_RANGE, 0, 1, INT_MAX, 1,
                 "width"    , GST_TYPE_INT_RANGE, 1, INT_MAX,
                 "height"   , GST_TYPE_INT_RANGE, 1, INT_MAX,
-                NULL);
+                nullptr);
 
     return caps;
 }
@@ -1317,7 +1317,7 @@ void QGstUtils::setMetaData(GstElement *element, const QMap<QByteArray, QVariant
                     GST_TAG_MERGE_REPLACE,
                     tagName.toUtf8().constData(),
                     tagValue.toString().toUtf8().constData(),
-                    NULL);
+                    nullptr);
                 break;
             case QVariant::Int:
             case QVariant::LongLong:
@@ -1325,14 +1325,14 @@ void QGstUtils::setMetaData(GstElement *element, const QMap<QByteArray, QVariant
                     GST_TAG_MERGE_REPLACE,
                     tagName.toUtf8().constData(),
                     tagValue.toInt(),
-                    NULL);
+                    nullptr);
                 break;
             case QVariant::Double:
                 gst_tag_setter_add_tags(GST_TAG_SETTER(element),
                     GST_TAG_MERGE_REPLACE,
                     tagName.toUtf8().constData(),
                     tagValue.toDouble(),
-                    NULL);
+                    nullptr);
                 break;
 #if GST_CHECK_VERSION(0, 10, 31)
             case QVariant::DateTime: {
@@ -1343,7 +1343,7 @@ void QGstUtils::setMetaData(GstElement *element, const QMap<QByteArray, QVariant
                     gst_date_time_new_local_time(
                                 date.date().year(), date.date().month(), date.date().day(),
                                 date.time().hour(), date.time().minute(), date.time().second()),
-                    NULL);
+                    nullptr);
                 break;
             }
 #endif
@@ -1604,7 +1604,7 @@ GstCaps *qt_gst_pad_get_current_caps(GstPad *pad)
 GstCaps *qt_gst_pad_get_caps(GstPad *pad)
 {
 #if GST_CHECK_VERSION(1,0,0)
-    return gst_pad_query_caps(pad, NULL);
+    return gst_pad_query_caps(pad, nullptr);
 #elif GST_CHECK_VERSION(0, 10, 26)
     return gst_pad_get_caps_reffed(pad);
 #else
@@ -1617,7 +1617,7 @@ GstStructure *qt_gst_structure_new_empty(const char *name)
 #if GST_CHECK_VERSION(1,0,0)
     return gst_structure_new_empty(name);
 #else
-    return gst_structure_new(name, NULL);
+    return gst_structure_new(name, nullptr);
 #endif
 }
 
@@ -1709,7 +1709,7 @@ static gint qt_gst_compare_ranks(GstPluginFeature *f1, GstPluginFeature *f2)
 
 GList *qt_gst_video_sinks()
 {
-    GList *list = NULL;
+    GList *list = nullptr;
 
 #if GST_CHECK_VERSION(0, 10, 31)
     list = gst_element_factory_list_get_elements(GST_ELEMENT_FACTORY_TYPE_SINK | GST_ELEMENT_FACTORY_TYPE_MEDIA_VIDEO,
@@ -1717,7 +1717,7 @@ GList *qt_gst_video_sinks()
 #else
     list = gst_registry_feature_filter(gst_registry_get_default(),
                                        (GstPluginFeatureFilter)qt_gst_videosink_factory_filter,
-                                       FALSE, NULL);
+                                       FALSE, nullptr);
     list = g_list_sort(list, (GCompareFunc)qt_gst_compare_ranks);
 #endif
 
diff --git a/src/gsttools/qgstvideorenderersink.cpp b/src/gsttools/qgstvideorenderersink.cpp
index 2e936ce36..9eb2531a1 100644
--- a/src/gsttools/qgstvideorenderersink.cpp
+++ b/src/gsttools/qgstvideorenderersink.cpp
@@ -360,7 +360,7 @@ static GstGLContext *gstGLDisplayContext(QAbstractVideoSurface *surface)
         qWarning() << "Could not create wrappped context for platform:" << glPlatform;
 
     GstGLContext *displayContext = nullptr;
-    GError *error = NULL;
+    GError *error = nullptr;
     gst_gl_display_create_context(display, appContext, &displayContext, &error);
     if (error) {
         qWarning() << "Could not create display context:" << error->message;
@@ -393,14 +393,14 @@ bool QVideoSurfaceGstDelegate::query(GstQuery *query)
         if (!m_gstGLDisplayContext)
             return false;
 
-        GstContext *context = NULL;
+        GstContext *context = nullptr;
         gst_query_parse_context(query, &context);
         context = context ? gst_context_copy(context) : gst_context_new(type, FALSE);
         GstStructure *structure = gst_context_writable_structure(context);
 #if GST_CHECK_VERSION(1,11,1)
-        gst_structure_set(structure, "context", GST_TYPE_GL_CONTEXT, m_gstGLDisplayContext, NULL);
+        gst_structure_set(structure, "context", GST_TYPE_GL_CONTEXT, m_gstGLDisplayContext, nullptr);
 #else
-        gst_structure_set(structure, "context", GST_GL_TYPE_CONTEXT, m_gstGLDisplayContext, NULL);
+        gst_structure_set(structure, "context", GST_GL_TYPE_CONTEXT, m_gstGLDisplayContext, nullptr);
 #endif
         gst_query_set_context(query, context);
         gst_context_unref(context);
@@ -583,10 +583,10 @@ GType QGstVideoRendererSink::get_type()
         {
             sizeof(QGstVideoRendererSinkClass),                    // class_size
             base_init,                                         // base_init
-            NULL,                                              // base_finalize
+            nullptr,                                           // base_finalize
             class_init,                                        // class_init
-            NULL,                                              // class_finalize
-            NULL,                                              // class_data
+            nullptr,                                           // class_finalize
+            nullptr,                                           // class_data
             sizeof(QGstVideoRendererSink),                         // instance_size
             0,                                                 // n_preallocs
             instance_init,                                     // instance_init
@@ -694,12 +694,12 @@ void QGstVideoRendererSink::handleShowPrerollChange(GObject *o, GParamSpec *p, g
     QGstVideoRendererSink *sink = reinterpret_cast<QGstVideoRendererSink *>(d);
 
     gboolean showPrerollFrame = true; // "show-preroll-frame" property is true by default
-    g_object_get(G_OBJECT(sink), "show-preroll-frame", &showPrerollFrame, NULL);
+    g_object_get(G_OBJECT(sink), "show-preroll-frame", &showPrerollFrame, nullptr);
 
     if (!showPrerollFrame) {
         GstState state = GST_STATE_VOID_PENDING;
         GstClockTime timeout = 10000000; // 10 ms
-        gst_element_get_state(GST_ELEMENT(sink), &state, NULL, timeout);
+        gst_element_get_state(GST_ELEMENT(sink), &state, nullptr, timeout);
         // show-preroll-frame being set to 'false' while in GST_STATE_PAUSED means
         // the QMediaPlayer was stopped from the paused state.
         // We need to flush the current frame.
@@ -714,7 +714,7 @@ GstStateChangeReturn QGstVideoRendererSink::change_state(
     QGstVideoRendererSink *sink = reinterpret_cast<QGstVideoRendererSink *>(element);
 
     gboolean showPrerollFrame = true; // "show-preroll-frame" property is true by default
-    g_object_get(G_OBJECT(element), "show-preroll-frame", &showPrerollFrame, NULL);
+    g_object_get(G_OBJECT(element), "show-preroll-frame", &showPrerollFrame, nullptr);
 
     // If show-preroll-frame is 'false' when transitioning from GST_STATE_PLAYING to
     // GST_STATE_PAUSED, it means the QMediaPlayer was stopped.
diff --git a/src/gsttools/qvideosurfacegstsink.cpp b/src/gsttools/qvideosurfacegstsink.cpp
index e3f174292..c6951bdef 100644
--- a/src/gsttools/qvideosurfacegstsink.cpp
+++ b/src/gsttools/qvideosurfacegstsink.cpp
@@ -356,10 +356,10 @@ GType QVideoSurfaceGstSink::get_type()
         {
             sizeof(QVideoSurfaceGstSinkClass),                    // class_size
             base_init,                                         // base_init
-            NULL,                                              // base_finalize
+            nullptr,                                           // base_finalize
             class_init,                                        // class_init
-            NULL,                                              // class_finalize
-            NULL,                                              // class_data
+            nullptr,                                           // class_finalize
+            nullptr,                                           // class_data
             sizeof(QVideoSurfaceGstSink),                         // instance_size
             0,                                                 // n_preallocs
             instance_init,                                     // instance_init
@@ -460,11 +460,11 @@ void QVideoSurfaceGstSink::handleShowPrerollChange(GObject *o, GParamSpec *p, gp
     QVideoSurfaceGstSink *sink = reinterpret_cast<QVideoSurfaceGstSink *>(d);
 
     gboolean showPrerollFrame = true; // "show-preroll-frame" property is true by default
-    g_object_get(G_OBJECT(sink), "show-preroll-frame", &showPrerollFrame, NULL);
+    g_object_get(G_OBJECT(sink), "show-preroll-frame", &showPrerollFrame, nullptr);
 
     if (!showPrerollFrame) {
         GstState state = GST_STATE_VOID_PENDING;
-        gst_element_get_state(GST_ELEMENT(sink), &state, NULL, GST_CLOCK_TIME_NONE);
+        gst_element_get_state(GST_ELEMENT(sink), &state, nullptr, GST_CLOCK_TIME_NONE);
         // show-preroll-frame being set to 'false' while in GST_STATE_PAUSED means
         // the QMediaPlayer was stopped from the paused state.
         // We need to flush the current frame.
@@ -478,7 +478,7 @@ GstStateChangeReturn QVideoSurfaceGstSink::change_state(GstElement *element, Gst
     QVideoSurfaceGstSink *sink = reinterpret_cast<QVideoSurfaceGstSink *>(element);
 
     gboolean showPrerollFrame = true; // "show-preroll-frame" property is true by default
-    g_object_get(G_OBJECT(element), "show-preroll-frame", &showPrerollFrame, NULL);
+    g_object_get(G_OBJECT(element), "show-preroll-frame", &showPrerollFrame, nullptr);
 
     // If show-preroll-frame is 'false' when transitioning from GST_STATE_PLAYING to
     // GST_STATE_PAUSED, it means the QMediaPlayer was stopped.
@@ -576,7 +576,7 @@ GstFlowReturn QVideoSurfaceGstSink::buffer_alloc(
     if (!buffer)
         return GST_FLOW_ERROR;
 
-    *buffer = NULL;
+    *buffer = nullptr;
 
     if (!sink->delegate->pool())
         return GST_FLOW_OK;
@@ -694,7 +694,7 @@ GstFlowReturn QVideoSurfaceGstSink::preroll(GstBaseSink *base, GstBuffer *buffer
 {
     VO_SINK(base);
     gboolean showPrerollFrame = true;
-    g_object_get(G_OBJECT(sink), "show-preroll-frame", &showPrerollFrame, NULL);
+    g_object_get(G_OBJECT(sink), "show-preroll-frame", &showPrerollFrame, nullptr);
 
     if (showPrerollFrame)
         return sink->delegate->render(buffer);