videoconvert element breaks udpsrc timeout messages - c++

Question

This code prints "Timeout received from udpsrc" each second. The videoconvert element is commented out of the pipeline. If I uncomment it then the messages stop printing.
// g++ gst_client.cpp `pkg-config --cflags gstreamer-1.0` `pkg-config --libs gstreamer-1.0`
#include <gst/gst.h>
#include <cstdlib>
#include <cstdio>
struct gstreamer_data {
GstElement* pipeline;
GstElement* udp_source;
GstElement* rtp_decoder;
GstElement* video_decoder;
GstElement* video_converter;
GstElement* fake_sink;
GMainLoop* main_loop;
};
static void error_callback(GstBus* bus, GstMessage* message, gstreamer_data* data) {
(void) bus;
GError* err;
gchar* debug_info;
gst_message_parse_error(message, &err, &debug_info);
g_printerr("Error received from element %s: %s\n", GST_OBJECT_NAME(message->src), err->message);
g_printerr("Debugging information: %s\n", debug_info ? debug_info : "none");
g_clear_error(&err);
g_free(debug_info);
g_main_loop_quit(data->main_loop);
}
static void element_callback(GstBus* bus, GstMessage* message, gpointer data) {
const GstStructure* st = gst_message_get_structure(message);
if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ELEMENT) {
if (gst_structure_has_name(st, "GstUDPSrcTimeout")) {
printf("Timeout received from udpsrc\n");
}
}
}
int main() {
gstreamer_data data;
GstStateChangeReturn ret;
GstBus* bus;
gst_init(NULL, NULL);
data.udp_source = gst_element_factory_make("udpsrc", "udp_source");
g_object_set(G_OBJECT(data.udp_source),
"port", 5000,
"caps", gst_caps_new_empty_simple("application/x-rtp"),
"timeout", 1000000000,
NULL);
data.rtp_decoder = gst_element_factory_make("rtph264depay", "rtp_decoder");
data.video_decoder = gst_element_factory_make("avdec_h264", "video_decoder");
data.video_converter = gst_element_factory_make("videoconvert", "video_converter");
data.fake_sink = gst_element_factory_make("fakesink", "fake_sink");
data.pipeline = gst_pipeline_new("pipeline");
if (
!data.pipeline ||
!data.udp_source ||
!data.rtp_decoder ||
!data.video_decoder ||
!data.video_converter ||
!data.fake_sink
)
{
g_printerr("Not all elements could be created.\n");
exit(-1);
}
gst_bin_add_many(
GST_BIN(data.pipeline),
data.udp_source,
data.rtp_decoder,
data.video_decoder,
//data.video_converter,
data.fake_sink,
NULL);
if (gst_element_link_many(
data.udp_source,
data.rtp_decoder,
data.video_decoder,
//data.video_converter,
data.fake_sink,
NULL) != TRUE)
{
g_printerr("Elements could not be linked.\n");
gst_object_unref(data.pipeline);
exit(-1);
}
bus = gst_element_get_bus(data.pipeline);
gst_bus_add_signal_watch(bus);
g_signal_connect(G_OBJECT(bus), "message::error", (GCallback) error_callback, &data);
g_signal_connect(G_OBJECT(bus), "message::element", (GCallback) element_callback, &data);
gst_object_unref(bus);
ret = gst_element_set_state(data.pipeline, GST_STATE_PLAYING);
if (ret == GST_STATE_CHANGE_FAILURE) {
g_printerr("Unable to set the pipeline to the playing state.\n");
gst_object_unref(data.pipeline);
exit(-1);
}
data.main_loop = g_main_loop_new(NULL, FALSE);
g_main_loop_run(data.main_loop);
return 0;
}
I have tried setting the debug level higher, but I'm not seeing anything to account for it. Is there something special about the videoconvert element?

Answer 1

Maybe you were sending data to that udpsrc after all?
I have confirmed that un-commenting the two lines that I do get the log messages as expected.