Handle delayed RTSP video connection.

src/FlightDisplay/VideoManager.cc

@@ -223,6 +223,15 @@ void VideoManager::_updateTimer()
             _videoRunning = false;
             _videoSurface->setLastFrame(0);
             emit videoRunningChanged();
+            if(_videoReceiver) {
+                if(isGStreamer()) {
+                    //-- Stop it
+                    _videoReceiver->stop();
+                    QThread::msleep(100);
+                    //-- And start over
+                    _videoReceiver->start();
+                }
+            }
         }
     }
     else

src/VideoStreaming/VideoReceiver.cc

@@ -16,15 +16,21 @@
 
 #include "VideoReceiver.h"
 #include <QDebug>
+#include <QUrl>
 
 VideoReceiver::VideoReceiver(QObject* parent)
     : QObject(parent)
 #if defined(QGC_GST_STREAMING)
     , _pipeline(NULL)
     , _videoSink(NULL)
+    , _socket(NULL)
+    , _serverPresent(false)
 #endif
 {
-
+#if defined(QGC_GST_STREAMING)
+    _timer.setSingleShot(true);
+    connect(&_timer, &QTimer::timeout, this, &VideoReceiver::_timeout);
+#endif
 }
 
 VideoReceiver::~VideoReceiver()
@@ -32,6 +38,9 @@ VideoReceiver::~VideoReceiver()
 #if defined(QGC_GST_STREAMING)
     stop();
     setVideoSink(NULL);
+    if(_socket) {
+        delete _socket;
+    }
 #endif
 }
 
@@ -66,6 +75,51 @@ static void newPadCB(GstElement * element, GstPad* pad, gpointer data)
 }
 #endif
 
+#if defined(QGC_GST_STREAMING)
+void VideoReceiver::_connected()
+{
+    //-- Server showed up. Now we start the stream.
+    _timer.stop();
+    delete _socket;
+    _socket = NULL;
+    _serverPresent = true;
+    start();
+}
+#endif
+
+#if defined(QGC_GST_STREAMING)
+void VideoReceiver::_socketError(QAbstractSocket::SocketError socketError)
+{
+    Q_UNUSED(socketError);
+    delete _socket;
+    _socket = NULL;
+    //-- Try again in 5 seconds
+    _timer.start(5000);
+}
+#endif
+
+#if defined(QGC_GST_STREAMING)
+void VideoReceiver::_timeout()
+{
+    //-- If socket is live, we got no connection nor a socket error
+    if(_socket) {
+        delete _socket;
+        _socket = NULL;
+    }
+    //-- RTSP will try to connect to the server. If it cannot connect,
+    //   it will simply give up and never try again. Instead, we keep
+    //   attempting a connection on this timer. Once a connection is
+    //   found to be working, only then we actually start the stream.
+    QUrl url(_uri);
+    _socket = new QTcpSocket;
+    connect(_socket, static_cast<void (QTcpSocket::*)(QAbstractSocket::SocketError)>(&QTcpSocket::error), this, &VideoReceiver::_socketError);
+    connect(_socket, &QTcpSocket::connected, this, &VideoReceiver::_connected);
+    //qDebug() << "Trying to connect to:" << url.host() << url.port();
+    _socket->connectToHost(url.host(), url.port());
+    _timer.start(5000);
+}
+#endif
+
 void VideoReceiver::start()
 {
 #if defined(QGC_GST_STREAMING)
@@ -78,8 +132,16 @@ void VideoReceiver::start()
         return;
     }
 
+    bool isUdp = _uri.contains("udp://");
+
     stop();
 
+    //-- For RTSP, check to see if server is there first
+    if(!_serverPresent && !isUdp) {
+        _timer.start(100);
+        return;
+    }
+
     bool running = false;
 
     GstElement*     dataSource  = NULL;
@@ -88,8 +150,6 @@ void VideoReceiver::start()
     GstElement*     parser      = NULL;
     GstElement*     decoder     = NULL;
 
-    bool isUdp = _uri.contains("udp://");
-
     do {
         if ((_pipeline = gst_pipeline_new("receiver")) == NULL) {
             qCritical() << "VideoReceiver::start() failed. Error with gst_pipeline_new()";
@@ -114,7 +174,7 @@ void VideoReceiver::start()
             }
             g_object_set(G_OBJECT(dataSource), "uri", qPrintable(_uri), "caps", caps, NULL);
         } else {
-            g_object_set(G_OBJECT(dataSource), "location", qPrintable(_uri), "latency", 0, NULL);
+            g_object_set(G_OBJECT(dataSource), "location", qPrintable(_uri), "latency", 0, "udp-reconnect", 1, "timeout", 5000000, NULL);
         }
 
         if ((demux = gst_element_factory_make("rtph264depay", "rtp-h264-depacketizer")) == NULL) {
@@ -208,6 +268,7 @@ void VideoReceiver::stop()
         gst_element_set_state(_pipeline, GST_STATE_NULL);
         gst_object_unref(_pipeline);
         _pipeline = NULL;
+        _serverPresent = false;
     }
 #endif
 }

src/VideoStreaming/VideoReceiver.h

@@ -18,6 +18,9 @@
 #define VIDEORECEIVER_H
 
 #include <QObject>
+#include <QTimer>
+#include <QTcpSocket>
+
 #if defined(QGC_GST_STREAMING)
 #include <gst/gst.h>
 #endif
@@ -33,10 +36,17 @@ public:
     void setVideoSink(GstElement* sink);
 #endif
 
-public Q_SLOTS:
-    void start  ();
-    void stop   ();
-    void setUri (const QString& uri);
+public slots:
+    void start      ();
+    void stop       ();
+    void setUri     (const QString& uri);
+
+private slots:
+#if defined(QGC_GST_STREAMING)
+    void _timeout       ();
+    void _connected     ();
+    void _socketError   (QAbstractSocket::SocketError socketError);
+#endif
 
 private:
 
@@ -52,6 +62,12 @@ private:
     GstElement* _videoSink;
 #endif
 
+    //-- Wait for Video Server to show up before starting
+#if defined(QGC_GST_STREAMING)
+    QTimer      _timer;
+    QTcpSocket* _socket;
+    bool        _serverPresent;
+#endif
 };
 
 #endif // VIDEORECEIVER_H