g_object_set assertion, G_IS_OBJECT (object) failed

[Michael Gruner]

The assertion failure means that gst_bin_get_by_name failed to return an element. In your case it did because there is no element named “testsink” in the pipeline. 

Change the pipeline to something like:

>    data->source=gst_parse_launch("v4l2src ! appsink name=testsink",NULL);

Michael

> On Jan 27, 2020, at 07:25, gonengoktug <gonengoktug at gmail.com> wrote:
> 
> Hi guys, as I posted before, I still want to capture frames from stream and
> to do that I write some code but it gives me error that I can't figure it
> out. Can anyone help me or make me understand this error. 
> 
> Here is my test code
> static void on_new_buffer_from_source (GstElement * elt, ProgramData * data)
> {
>  GstSample *sample;
>  guint size;
>  gpointer raw_buffer;
>  GstBuffer *app_buffer, *buffer;
>  GstElement *source;
>  GstMapInfo map;
>  GstStructure *s;
>  const int width=g_value_get_int(gst_structure_get_value(s, "width"));
>  const int height=g_value_get_int(gst_structure_get_value(s, "height"));
> 
>  sample=gst_app_sink_pull_sample(GST_APP_SINK(elt));
>  buffer=gst_sample_get_buffer(sample);
>  if(gst_buffer_map(buffer,&map,GST_MAP_READ))
>      g_printerr("frame is catched");
>  else
>      g_printerr("frame is missed");
>   cv::Mat
> frame(cv::Size(width,height),CV_8UC3,(char*)map.data,cv::Mat::AUTO_STEP);
>   cv::namedWindow("frames",CV_WINDOW_AUTOSIZE);
>   cv::imshow("frame",frame);
> 
> 
> }
> 
> int main(int argc, char*argv[]) {
> 
>    gchar *filename = NULL;
>    ProgramData *data;
>    gchar *string = NULL;
>    GstBus *bus = NULL;
>    GstElement *testsink = NULL;
>    GstElement *testsource = NULL;
> 
>    gst_init(&argc,&argv);
> 
> 
>    data = g_new0 (ProgramData, 1);
> 
>    data->loop = g_main_loop_new (NULL, FALSE);
> 
>    data->source=gst_parse_launch("v4l2src ! autovideosink",NULL);
> 
>    bus = gst_element_get_bus (data->source);
>    gst_bus_add_watch (bus, (GstBusFunc) on_source_message, data);
> 
>    testsink = gst_bin_get_by_name (GST_BIN (data->source), "testsink");
>    g_object_set(G_OBJECT(testsink), "emit-signals", TRUE, "sync", FALSE,
> NULL);
>    g_signal_connect (testsink, "new-buffer", G_CALLBACK
> (on_new_buffer_from_source), data);
>    gst_object_unref (testsink);
> }
> I tried to debug but whenever g_object_set command runs, gives me assertion
> error. Also you can give me any advice about my code. Thanks
> 
> 
> 
> 
> 
> --
> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
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