问为什么我不能在本地主机上通过UDP发送数据呢？

EN

console_out_inf("TESTING", "Starting work with test elements");
gint port = 5078;
// TEST PIPELINE OUT
gst_bin_add_many(GST_BIN(GSD->pipetest_out), GSD->testsrc, GSD->udpsink, NULL);
gchar* host = "127.0.0.1";
g_object_set(GSD->udpsink, "port", port, NULL);
g_object_set(GSD->udpsink, "host", host, NULL);
if (!gst_element_link(GSD->testsrc, GSD->udpsink))
    console_out_bad("STREAMING", "Error linking test udp elements -- SEND");
else
    console_out_yes("STREAMING", "Correctly linked test udp elements -- SEND");

// TEST PIPELINE IN
gst_bin_add_many(GST_BIN(GSD->pipetest_in), GSD->udpsrc, GSD->autovideosink, NULL);

gst_element_set_state(GSD->udpsrc, GST_STATE_NULL);
g_object_set(GSD->udpsrc, "port", port, NULL);

if (!gst_element_link(GSD->udpsrc, GSD->autovideosink))
    console_out_bad("STREAMING", "Error linking test udp elements -- RECEIVE");
else
    console_out_yes("STREAMING", "Correctly linked test udp elements -- RECEIVE");
// PLAY TEST PIPELINE OUT
GstStateChangeReturn ret1;
ret1 = gst_element_set_state(GSD->pipetest_out, GST_STATE_PLAYING);
if (ret1 == GST_STATE_CHANGE_FAILURE)
    console_out_bad("TESTING", "Failed playing pipetest out");
else
    console_out_yes("TESTING", "Correctly played pipetest out");

// PLAY TEST PIPELINE IN
GstStateChangeReturn ret2;
ret2 = gst_element_set_state(GSD->pipetest_in, GST_STATE_PLAYING);
if (ret2 == GST_STATE_CHANGE_FAILURE)
    console_out_bad("TESTING", "Failed playing pipetest in");
else
    console_out_yes("TESTING", "Correctly played pipetest in");

// PRINT PIPELINES
GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(GSD->pipetest_out), GST_DEBUG_GRAPH_SHOW_ALL, "pipetest_out");
GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(GSD->pipetest_in), GST_DEBUG_GRAPH_SHOW_ALL, "pipetest_in");