Joining the pictures in the same window - c

Question

I want to display two pictures in the same window. This code displays them in two different windows.
Is there a solution for joining the two pictures in the same window?
#include <gst/gst.h>
#include <glib.h>
static gboolean bus_call (GstBus *bus, GstMessage *msg, gpointer data)
{
GMainLoop *loop = (GMainLoop *) data;
switch (GST_MESSAGE_TYPE (msg)) {
case GST_MESSAGE_EOS:
g_print ("End of stream\n");
g_main_loop_quit (loop);
break;
case GST_MESSAGE_ERROR: {
gchar *debug;
GError *error;
gst_message_parse_error (msg, &error, &debug);
g_free (debug);
g_printerr ("Error: %s\n", error->message);
g_error_free (error);
g_main_loop_quit (loop);
break;
}
default:
break;
}
return TRUE;
}
static void on_pad_added (GstElement *element, GstPad *pad, gpointer data)
{
GstPad *sinkpad;
GstElement *decoder = (GstElement *) data;
/* We can now link this pad with the vorbis-decoder sink pad */
g_print ("Dynamic pad created, linking demuxer/decoder\n");
sinkpad = gst_element_get_static_pad (decoder, "sink");
gst_pad_link (pad, sinkpad);
gst_object_unref (sinkpad);
}
int main (int argc, char *argv[]) {
GMainLoop *loop;
GstElement *pipeline,*freeze,*clrspace, *source1, *source2, *videobox1,*videobox2, *mixer,*sink,*queuevideo;
GstBus *bus;
loop = g_main_loop_new (NULL, FALSE);
gst_init (&argc, &argv);
/* Create gstreamer elements */
pipeline = gst_pipeline_new ("player");
source1 = gst_element_factory_make ("playbin2", "dec1");
source2 = gst_element_factory_make ("playbin2", "dec2");
freeze = gst_element_factory_make ("imagefreeze", "fr");
videobox1 = gst_element_factory_make ("videobox", "videobox1");
videobox2 = gst_element_factory_make ("videobox", "videobox2");
clrspace = gst_element_factory_make ("ffmpegcolorspace", "clrspace");
mixer = gst_element_factory_make ("videomixer", "mixer");
queuevideo = gst_element_factory_make ("queue", "queue-video");
sink = gst_element_factory_make ("autovideosink", "sink");
if (!pipeline || !source1 || !source2 || !sink || !mixer ||!freeze || !clrspace || !queuevideo ) {
g_printerr ("One element could not be created. Exiting.\n");
exit(1);
}
g_object_set (source1, "uri", "http://www.logotheque.fr/6396-2/logo+RMC+INFO.jpg", NULL);
g_object_set (source2, "uri", "http://www.logotheque.fr/6396-2/logo+RMC+INFO.jpg", NULL);
g_object_set(videobox1,"border-alpha",0,"top",0,"left",0,NULL);
g_object_set(videobox2,"border-alpha",0,"top",0,"left",-200,NULL);
/* we add a message handler */
bus = gst_pipeline_get_bus(GST_PIPELINE (pipeline));
gst_bus_add_watch (bus, bus_call, loop);
gst_object_unref (bus);
/* we add all elements into the pipeline */
gst_bin_add_many (GST_BIN(pipeline), source1,mixer, clrspace, freeze,videobox1, sink, NULL);
/* we link the elements together */
gst_element_link_many (source2, mixer, clrspace, freeze,videobox2,sink, NULL);
//gst_element_link_many(source[1], mixer, NULL);
g_signal_connect (source1, "pad-added", G_CALLBACK (on_pad_added), queuevideo);
g_signal_connect (source2, "pad-added", G_CALLBACK (on_pad_added), queuevideo);
/* Set the pipeline to "playing" state*/
gst_element_set_state(pipeline, GST_STATE_PLAYING);
/* Iterate */
g_print ("Running...\n");
g_main_loop_run (loop);
/* Out of the main loop, clean up nicely */
g_print ("Returned, stopping playback\n");
gst_element_set_state (pipeline, GST_STATE_NULL);
g_print ("Deleting pipeline\n");
gst_object_unref (GST_OBJECT(pipeline));
}

Answer 1

Here is how to combine two images with gstreamer from the command line :
gst-launch-1.0 uridecodebin uri=file:///home/meh/Pictures/questions.jpg ! videoscale ! video/x-raw, width=320, height=240 ! imagefreeze ! videomixer name=m sink_1::xpos=320 ! autovideosink uridecodebin uri=file:///home/meh/Pictures/testsrc.png ! videoscale ! video/x-raw, width=320, height=240 ! imagefreeze ! m.
Explanation :
We create two decoders for the images, resize them with videoscale to an arbitrary size (here 320 x 240), freeze them and send them to videomixer. videomixer has the x position of sink_1 set to 320, which offsets the first image so that the second one appears as well.