Detect video stream.

src/FlightDisplay/FlightDisplayView.qml

@@ -114,7 +114,6 @@ Item {
                 _flightMap.updateMapPosition(true /* force */)
             } else {
                 _flightVideo = item
-                _flightVideo.visible = true
             }
         }
     }
@@ -144,20 +143,17 @@ Item {
             onLoaded: {
                 if(_mainIsMap) {
                     _flightVideo = item
-                    _flightVideo.visible = true
                 } else {
                     _flightMap = item
                     _savedZoomLevel = _flightMap.zoomLevel
                     _flightMap.zoomLevel = _savedZoomLevel - 3
                 }
-                pip.visible = _controller.hasVideo
             }
         }
         MouseArea {
             anchors.fill: parent
             onClicked: {
                 _mainIsMap = !_mainIsMap
-                pip.visible = false
                 reloadContents();
                 QGroundControl.saveBoolGlobalSetting(_mainIsMapKey, _mainIsMap)
             }

src/FlightDisplay/FlightDisplayViewController.cc

@@ -34,6 +34,7 @@ const char* kMainFlightDisplayViewControllerGroup = "FlightDisplayViewController
 
 FlightDisplayViewController::FlightDisplayViewController(QObject *parent)
     : QObject(parent)
+    , _videoRunning(false)
 {
     /*
      * This is the receiving end of an UDP RTP stream. The sender can be setup with this command:
@@ -65,6 +66,8 @@ FlightDisplayViewController::FlightDisplayViewController(QObject *parent)
     _videoReceiver->setUri(QLatin1Literal("udp://0.0.0.0:5000"));
 #if defined(QGC_GST_STREAMING)
     _videoReceiver->setVideoSink(_videoSurface->videoSink());
+    connect(&_frameTimer, &QTimer::timeout, this, &FlightDisplayViewController::_updateTimer);
+    _frameTimer.start(1000);
 #endif
 }
 
@@ -72,3 +75,33 @@ FlightDisplayViewController::~FlightDisplayViewController()
 {
 
 }
+
+#if defined(QGC_GST_STREAMING)
+void FlightDisplayViewController::_updateTimer(void)
+{
+    if(_videoRunning)
+    {
+        time_t elapsed = 0;
+        if(_videoSurface)
+        {
+            elapsed = time(0) - _videoSurface->lastFrame();
+        }
+        if(elapsed > 2)
+        {
+            _videoRunning = false;
+            _videoSurface->setLastFrame(0);
+            emit videoRunningChanged();
+        }
+    }
+    else
+    {
+        if(_videoSurface && _videoSurface->lastFrame()) {
+            if(!_videoRunning)
+            {
+                _videoRunning = true;
+                emit videoRunningChanged();
+            }
+        }
+    }
+}
+#endif

src/FlightDisplay/FlightDisplayViewController.h

@@ -25,6 +25,7 @@ This file is part of the QGROUNDCONTROL project
 #define FlightDisplayViewController_H
 
 #include <QObject>
+#include <QTimer>
 
 #include "VideoSurface.h"
 #include "VideoReceiver.h"
@@ -42,15 +43,29 @@ public:
     Q_PROPERTY(VideoSurface*    videoSurface    MEMBER _videoSurface    CONSTANT);
     Q_PROPERTY(VideoReceiver*   videoReceiver   MEMBER _videoReceiver   CONSTANT);
 
+    Q_PROPERTY(bool             videoRunning    READ videoRunning       NOTIFY videoRunningChanged)
+
 #if defined(QGC_GST_STREAMING)
     bool    hasVideo            () { return true; }
 #else
     bool    hasVideo            () { return false; }
 #endif
 
+    bool videoRunning() { return _videoRunning; }
+
+signals:
+    void videoRunningChanged();
+
+private:
+    void _updateTimer(void);
+
 private:
     VideoSurface*   _videoSurface;
     VideoReceiver*  _videoReceiver;
+    bool            _videoRunning;
+#if defined(QGC_GST_STREAMING)
+    QTimer          _frameTimer;
+#endif
 };
 
 #endif

src/FlightDisplay/FlightDisplayViewVideo.qml

@@ -34,22 +34,38 @@ import QGroundControl.Vehicle       1.0
 import QGroundControl.Controllers   1.0
 
 
-QGCVideoBackground {
-    anchors.fill:   parent
-    display:        _controller.videoSurface
-    receiver:       _controller.videoReceiver
-
-    /* TODO: Come up with a way to make this an option
-    QGCAttitudeHUD {
-        id:                 attitudeHUD
-        visible:            !_mainIsMap
-        rollAngle:          _roll
-        pitchAngle:         _pitch
-        width:              ScreenTools.defaultFontPixelSize * (30)
-        height:             ScreenTools.defaultFontPixelSize * (30)
-        active:             multiVehicleManager.activeVehicleAvailable
-        z:                  QGroundControl.zOrderWidgets
+Item {
+    id: root
+    Rectangle {
+        id:             noVideo
+        anchors.fill:   parent
+        color:          "black"
+        visible:        !_controller.videoRunning
+        QGCLabel {
+            text:               "NO VIDEO"
+            font.weight:        Font.DemiBold
+            color:              "white"
+            font.pixelSize:     ScreenTools.defaultFontPixelSize * 1.5
+            anchors.centerIn:   parent
+        }
+    }
+    QGCVideoBackground {
+        anchors.fill:   parent
+        display:        _controller.videoSurface
+        receiver:       _controller.videoReceiver
+        visible:        _controller.videoRunning
+        runVideo:       true
+        /* TODO: Come up with a way to make this an option
+        QGCAttitudeHUD {
+            id:                 attitudeHUD
+            visible:            !_mainIsMap
+            rollAngle:          _roll
+            pitchAngle:         _pitch
+            width:              ScreenTools.defaultFontPixelSize * (30)
+            height:             ScreenTools.defaultFontPixelSize * (30)
+            active:             multiVehicleManager.activeVehicleAvailable
+            z:                  QGroundControl.zOrderWidgets
+        }
+        */
     }
-    */
-
 }

src/FlightMap/QGCVideoBackground.qml

@@ -35,10 +35,11 @@ VideoItem {
     id: videoBackground
     property var display
     property var receiver
+    property var runVideo:  false
     surface: display
-    onVisibleChanged: {
+    onRunVideoChanged: {
         if(videoBackground.receiver && videoBackground.display) {
-            if(videoBackground.visible) {
+            if(videoBackground.runVideo) {
                 videoBackground.receiver.start();
             } else {
                 videoBackground.receiver.stop();
@@ -46,7 +47,7 @@ VideoItem {
         }
     }
     Component.onCompleted: {
-        if(videoBackground.visible && videoBackground.receiver) {
+        if(videoBackground.runVideo && videoBackground.receiver) {
             videoBackground.receiver.start();
         }
     }

src/VideoStreaming/VideoSurface.cc

@@ -39,6 +39,7 @@ VideoSurface::VideoSurface(QObject *parent)
     : QObject(parent)
 #if defined(QGC_GST_STREAMING)
     , _data(new VideoSurfacePrivate)
+    , _lastFrame(0)
 #endif
 {
 }
@@ -68,6 +69,7 @@ GstElement* VideoSurface::videoSink() const
 
 void VideoSurface::onUpdate()
 {
+    _lastFrame = time(0);
     Q_FOREACH(QQuickItem *item, _data->items) {
         item->update();
     }

src/VideoStreaming/VideoSurface.h

@@ -54,6 +54,8 @@ public:
      */
 #if defined(QGC_GST_STREAMING)
     GstElement* videoSink() const;
+    time_t      lastFrame() { return _lastFrame; }
+    void        setLastFrame(time_t t) { _lastFrame = t; }
 #endif
 
 protected:
@@ -66,6 +68,7 @@ private:
     friend class VideoItem;
 #if defined(QGC_GST_STREAMING)
     VideoSurfacePrivate * const _data;
+    time_t _lastFrame;
 #endif
 };