Videomixer fails on sources rather than Videotestsrc - gstreamer

Question

I want to play two different local video files at the same time in a single
window. The code below without demux and decoder works fine.
static void play_video(){
GMainLoop *loop;
GstElement *pipeline,*videomixer;
GstElement *src,*sink,*filter,*csp,*videobox;
GstElement *src1,*filter1,*csp1,*videobox1;
GstElement *srcb,*filterb,*cspb,*videoboxb;
GstCaps *filtercaps,*filtercaps1,*filtercapsb;
GstPad *pad,*pad1;
const char pattern = "snow";
loop = g_main_loop_new(NULL, FALSE);
pipeline = gst_pipeline_new("my-pipeline");
src = gst_element_factory_make ("videotestsrc","src");
src1 = gst_element_factory_make ("videotestsrc","src1");
g_object_set (G_OBJECT (src), "pattern", 10, NULL);
filter = gst_element_factory_make("capsfilter","filter");
filter1 = gst_element_factory_make("capsfilter","filter1");
csp = gst_element_factory_make("ffmpegcolorspace","csp");
csp1 = gst_element_factory_make("ffmpegcolorspace","csp1");
/**/
videobox=gst_element_factory_make("videobox","videobox");
g_object_set(videobox,"top",0,"bottom",0,"left",0,"right",0,NULL);
videobox1=gst_element_factory_make("videobox","videobox1");
g_object_set(videobox1,"top",-20,"bottom",0,"left",0,"right",0,NULL);
videomixer=gst_element_factory_make("videomixer","videomixer");
/**/
sink = gst_element_factory_make("xvimagesink","sink");
if(sink == NULL)
sink = gst_element_factory_make("ximagesink","sink");
if(sink == NULL)
g_error("'ximagesink' yaratılamadı.");
gst_bin_add_many(GST_BIN(pipeline),src,filter,videobox,videomixer,csp,sink,
src1,filter1,videobox1,csp1,NULL);
gst_element_link_many(src,filter,csp,videobox,videomixer,NULL);
gst_element_link_many(src1,filter1,csp1,videobox1,videomixer,NULL);
/*
videotestsrc pattern="snow" ! video/x-raw-yuv, framerate=1/1, width=350,
height=250 ! \
textoverlay font-desc="Sans 24" text="CAM2" valign=top halign=left
shaded-background=true ! \
videobox border-alpha=0 top=-200 left=-450 ! mix. \
*/
gst_element_link_many(videomixer,sink,NULL);
filtercaps = gst_caps_new_simple ("video/x-raw-rgb",
"width", G_TYPE_INT, 1024,
"height", G_TYPE_INT, 768,
"framerate", GST_TYPE_FRACTION, 25, 1,
"bpp", G_TYPE_INT, 16,
"depth", G_TYPE_INT, 16,
"endianness", G_TYPE_INT, G_BYTE_ORDER,
NULL);
filtercaps1 = gst_caps_new_simple ("video/x-raw-rgb",
"width", G_TYPE_INT, 200,
"height", G_TYPE_INT, 500,
"framerate", GST_TYPE_FRACTION, 25, 1,
"bpp", G_TYPE_INT, 16,
"depth", G_TYPE_INT, 16,
"endianness", G_TYPE_INT, G_BYTE_ORDER,
NULL);
g_object_set (G_OBJECT (filter), "caps", filtercaps, NULL);
gst_caps_unref (filtercaps);
g_object_set (G_OBJECT (filter1), "caps", filtercaps1, NULL);
gst_caps_unref (filtercaps1);
/*pad = gst_element_get_pad (src, "src");
pad1 = gst_element_get_pad (src1, "src1");
//gst_pad_add_buffer_probe (pad, G_CALLBACK (cb_have_data), NULL);
//gst_pad_add_buffer_probe (pad1, G_CALLBACK (cb_have_data), NULL);
//gst_object_unref (pad);
//gst_object_unref (pad1);*/
/* run */
gst_element_set_state (pipeline, GST_STATE_PLAYING);
/* wait until it's up and running or failed */
if (gst_element_get_state (pipeline, NULL, NULL, -1) ==
GST_STATE_CHANGE_FAILURE) {
g_error ("Failed to go into PLAYING state");
}
g_print ("Running ...\n");
g_main_loop_run (loop);
/* exit */
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
}
Problem is when I replace the videotestsrc with filesrc it fails and the
only error message I get is "Could not lookup object NULL on signal destroy
of object window". I'm not an gstreamer expert and my opinion is I am
failing at setting demux and decoder.
static void play_video5(){
GMainLoop *loop;
GstElement *pipeline,*videomixer;
GstElement *src,*sink,*filter,*csp,*videobox;
GstElement *src1,*filter1,*csp1,*videobox1;
GstElement *srcb,*filterb,*cspb,*videoboxb;
GstCaps *filtercaps,*filtercaps1,*filtercapsb;
GstPad *pad,*pad1;
GstElement *demux,*decoder;
const char pattern = "snow";
loop = g_main_loop_new(NULL, FALSE);
pipeline = gst_pipeline_new("my-pipeline");
//Source
src = gst_element_factory_make ("videotestsrc","src");
src1 = gst_element_factory_make ("filesrc","src1");
g_object_set (G_OBJECT (src1), "location", "file:///root/yu.mp4", NULL);
//Demux
demux = gst_element_factory_make ("mpegdemux", "demux");
//Decoder
decoder = gst_element_factory_make ("decodebin", "decoder");
// decoder = gst_element_factory_make ("ffdec_mpeg4","mpeg4-decoder");
//Filter
filter = gst_element_factory_make("capsfilter","filter");
filter1 = gst_element_factory_make("capsfilter","filter1");
//Colorspace
csp = gst_element_factory_make("ffmpegcolorspace","csp");
csp1 = gst_element_factory_make("ffmpegcolorspace","csp1");
//Videobox
videobox=gst_element_factory_make("videobox","videobox");
g_object_set(videobox,"top",0,"bottom",0,"left",0,"right",0,NULL);
videobox1=gst_element_factory_make("videobox","videobox1");
g_object_set(videobox1,"top",-20,"bottom",0,"left",0,"right",0,NULL);
//videomixer
videomixer=gst_element_factory_make("videomixer","videomixer");
//Sink
sink = gst_element_factory_make("xvimagesink","sink");
if(sink == NULL)
sink = gst_element_factory_make("ximagesink","sink");
if(sink == NULL)
g_error("'ximagesink' yaratılamadı.");
//Add to Bin
gst_bin_add_many(GST_BIN(pipeline),src,filter,videobox,videomixer,csp,
src1,decoder,filter1,videobox1,csp1,sink,NULL);
//Link Elements
gst_element_link(src,filter);
gst_element_link(filter,csp);
gst_element_link(csp,videobox);
gst_element_link(videobox, videomixer);
gst_element_link(src1,decoder);
gst_element_link(decoder,filter1);
// gst_element_link(decoder,csp1);
gst_element_link(filter1,csp1);
gst_element_link(csp1,videobox1);
gst_element_link(videobox1, videomixer);
gst_element_link(videomixer,sink);
//Cap definition
filtercaps = gst_caps_new_simple ("video/x-raw-rgb",
"width", G_TYPE_INT, 1024,
"height", G_TYPE_INT, 768,
"framerate", GST_TYPE_FRACTION, 25, 1,
"bpp", G_TYPE_INT, 16,
"depth", G_TYPE_INT, 16,
"endianness", G_TYPE_INT, G_BYTE_ORDER,
NULL);
filtercaps1 = gst_caps_new_simple ("video/x-raw-yuv",
"width", G_TYPE_INT, 640,
"height", G_TYPE_INT, 480,
"framerate", GST_TYPE_FRACTION, 25, 1,
/*"bpp", G_TYPE_INT, 16,
"depth", G_TYPE_INT, 16,
"endianness", G_TYPE_INT, G_BYTE_ORDER,*/
NULL);
//Cap to Filter
g_object_set (G_OBJECT (filter), "caps", filtercaps, NULL);
gst_caps_unref (filtercaps);
g_object_set (G_OBJECT (filter1), "caps", filtercaps1, NULL);
gst_caps_unref (filtercaps1);
/* run */
gst_element_set_state (pipeline, GST_STATE_PLAYING);
/* wait until it's up and running or failed */
if (gst_element_get_state (pipeline, NULL, NULL, -1) ==
GST_STATE_CHANGE_FAILURE) {
g_error ("Failed to go into PLAYING state");
}
g_print ("Running ...\n");
g_main_loop_run (loop);
/* exit */
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
}
Any ideas or corrections are welcome.

Answer 1

Several issues:
filesrc does not take uris, but file-paths
/* wait until it's up and running or failed */ + the code below is not needed, better listen on the bus for the error and warning messages
"Could not lookup object NULL on signal destroy of object window" has nothing to do with gstreamer
the whole videobox business is not needed as the pads of videomixer have xpos, ypos and zorder properties