pad.c

#include <gst/gst.h>

gboolean on_message(GstBus *bus, GstMessage *message, gpointer p)
{
	GMainLoop *mainloop = p;

	(void)bus;
	if ((GST_MESSAGE_TYPE(message) & GST_MESSAGE_EOS)) {
		g_print("message: eos\n");
		g_main_loop_quit(mainloop);
	}

	return TRUE;
}

GstPadProbeReturn on_probe(GstPad *pad, GstPadProbeInfo *info, gpointer unused)
{
	GstEvent *event;
	(void)pad;
	(void)unused;

	event = gst_pad_probe_info_get_event(info);
	g_print("event: %s\n", GST_EVENT_TYPE_NAME(event));

	return GST_PAD_PROBE_OK;
}

int main(int argc, char *argv[])
{
	GMainLoop *mainloop;
	GstElement *pipeline;
	GError *error = NULL;
	GstBus *bus;
	GstElement *src;
	GstElement *sink;
	GstPad *pad1;
	GstPad *pad2;

	gst_init(&argc, &argv);

	mainloop = g_main_loop_new(NULL, FALSE);
	pipeline = gst_parse_launch("filesrc location=a.txt ! fdsink", &error);
	bus = gst_element_get_bus(pipeline);
	gst_bus_add_watch(bus, on_message, mainloop);

	src = gst_bin_get_by_name(GST_BIN(pipeline), "filesrc0");
	pad1 = gst_element_get_static_pad(src, "src");
	pad2 = gst_pad_get_peer(pad1);
	sink = gst_pad_get_parent_element(pad2);
	g_print("name: %s\n", gst_element_get_name(sink));

	gst_pad_add_probe(pad1, GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM, on_probe, NULL, NULL);

	gst_element_set_state(pipeline, GST_STATE_PLAYING);
	g_main_loop_run(mainloop);

	return 0;
}