How to do gstreamer streaming using GstElement and udpsrc in qwidget - gstreamer

Question

I am trying to embed streaming of IP camera using udpsrc in qwidget. Below pipeline works :
gst-launch-1.0 udpsrc port=20000 ! application/x-rtp,encoding-name=JPEG,payload=26,width=640,height=460 ! rtpjpegdepay ! jpegparse ! jpegdec ! videoconvert ! videoscale ! ximagesink sync=false
When tried to embed in qwidget, it's showing a plain window. My code is as follows :
#include <glib.h>
#include <gst/gst.h>
#include <gst/video/videooverlay.h>
#include <QApplication>
#include <QTimer>
#include <QWidget>
int main(int argc, char *argv[])
{
if (!g_thread_supported ())
g_thread_init (NULL);
gst_init (&argc, &argv);
QApplication app(argc, argv);
app.connect(&app, SIGNAL(lastWindowClosed()), &app, SLOT(quit ()));
// prepare the pipeline
GstElement *pipeline = gst_pipeline_new ("pipeline");
GstElement *src = gst_element_factory_make ("udpsrc", NULL);
GstCaps *caps = gst_caps_from_string ("application/x-rtp,encoding-name=JPEG,payload=26,width=640,height=460");
g_object_set(G_OBJECT(src),
"port", 20000,
"caps", caps, NULL);
GstElement *parser = gst_element_factory_make ("rtpjpegdepay", NULL);
GstElement *mux = gst_element_factory_make ("jpegparse", NULL);
GstElement *parse2 = gst_element_factory_make ("jpegdec", NULL);
GstElement *dec = gst_element_factory_make ("videoconvert", NULL);
GstElement *conv = gst_element_factory_make ("videoscale", NULL);
GstElement *sink = gst_element_factory_make ("ximagesink", NULL);
g_object_set(G_OBJECT(sink), "sync", FALSE, NULL);
gst_bin_add_many (GST_BIN (pipeline), src, parser, mux, parse2, dec, conv, sink, NULL);
gst_element_link (src, sink);
GstState state, pending;
//this is the call to overlay the gstreamer's output to the Qt Widgets...
gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (sink), xwinid);
GstBus *bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
gst_object_unref (bus);
GstStateChangeReturn sret = gst_element_set_state (pipeline, GST_STATE_PLAYING); //Playback can be initiated by setting the element to PLAYING state using gst_element_set_state()
qDebug()<<"####-1"<<sret;
if (sret == GST_STATE_CHANGE_FAILURE) {
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
// Exit application
QTimer::singleShot(0, QApplication::activeWindow(), SLOT(quit()));
}
gst_element_get_state (pipeline,
&state,
&pending,
10);
qDebug()<<state<<pending;
window->show();
app.exec();
g_main_loop_run (loop);
return 0;
}

Answer 1

I solved it by Creating pipeline using gst_parse_launch()
GstElement *pipeline_2= gst_parse_launch("udpsrc port=20000 ! application/x-rtp,encoding-name=JPEG,payload=26 ! rtpjpegdepay ! jpegparse ! jpegdec ! videoconvert ! videoscale ! ximagesink name=mySink", NULL);
GstElement *sink = gst_bin_get_by_name((GstBin*)pipeline_2,"mySink");
QWidget *window = new QWidget();
window->setWindowTitle("udpsrc video stream");
window->resize(700, 700);
WId xwinid = window->winId();
gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (sink), (guintptr)xwinid);
window->show();
GstStateChangeReturn sret = gst_element_set_state (pipeline_2, GST_STATE_PLAYING);
Hope this helps.