gstreamer: rtspsrc "internal data stream error" when i want to build my own pipeline

Question

gst-launch-1.0 rtspsrc location=rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov is-live=true latency=200 name=src src. ! rtph264depay ! h264parse ! avdec_h264 ! queue ! autovideosink

I'm trying to write the pipeline as c application. This command runs successfully. But C-application give error:

Error received from element udpsrc2: Internal data stream error.

And the Debugging information:

../libs/gst/base/gstbasesrc.c(3127): gst_base_src_loop (): /GstPipeline:test-pipeline/GstRTSPSrc:rtspsrc/GstUDPSrc:udpsrc2:streaming stopped, reason not-negotiated (-4)

Here's my c code:

#include <gst/gst.h>

static void cb_new_rtspsrc_pad(GstElement *element, GstPad *pad, gpointer data)
{
    GstPad *sink_pad = gst_element_get_static_pad (GST_ELEMENT(data), "sink");
    GstPadLinkReturn ret;
    GstCaps *pad_caps = NULL;
    GstStructure *pad_caps_struct = NULL;
    const gchar *pad_caps_type = NULL;

    g_print ("Received new pad '%s' from '%s':\n", GST_PAD_NAME (pad), GST_ELEMENT_NAME (element));

    /* If our converter is already linked, we have nothing to do here */
    if (gst_pad_is_linked (sink_pad)) {
        g_print ("We are already linked. Ignoring.\n");
        goto exit;
    }

    /* Get the new pad's type */
    pad_caps = gst_pad_get_current_caps (pad);
    pad_caps_struct = gst_caps_get_structure (pad_caps, 0);
    pad_caps_type = gst_structure_get_name (pad_caps_struct);

    /* Attempt the link */
    ret = gst_pad_link (pad, sink_pad);
    if (GST_PAD_LINK_FAILED (ret)) {
        g_print ("Type is '%s' but link failed.\n", pad_caps_type);
    } else {
        g_print ("Link succeeded (type '%s').\n", pad_caps_type);
    }

exit:
    /* Unreference the new pad's caps, if we got them */
    if (pad_caps != NULL)
        gst_caps_unref (pad_caps);

    /* Unreference the sink pad */
    gst_object_unref (sink_pad);
}


int main(int argc, char *argv[])
{
    GstElement *pipeline, *rtspsrc, *h264depay, *h264parse, *h264decoder, *que, *h264sink;
    GstBus *bus;
    GstMessage *msg;
    GstStateChangeReturn ret;
    gboolean terminate = FALSE;

    /* Initialize GStreamer */
    gst_init(&argc, &argv);

    /* Create the elements */
    rtspsrc = gst_element_factory_make ("rtspsrc", "rtspsrc");                 // Availability: Sometimes
    h264depay = gst_element_factory_make ("rtph264depay", "h264depay");        // Availability: Always
    h264parse = gst_element_factory_make ("h264parse", "h264parse");           // Availability: Always
    h264decoder = gst_element_factory_make ("avdec_h264", "h264decoder");      // Availability: Always
    que = gst_element_factory_make ("queue", "queue");                         // Availability: Always
    h264sink = gst_element_factory_make ("autoaudiosink", "sink");             // Availability: Always

    /* Create the empty pipeline */
    pipeline = gst_pipeline_new("test-pipeline");

    if (!pipeline || !rtspsrc || !h264depay || !h264parse || !h264decoder || !que || !h264sink) {
        g_printerr("[ERROR-main]: Not all elements could be created.\n");
        return -1;
    } else {
        g_print("[DEBUG-main]: Elements have been created.\n");
    }

    gst_bin_add_many(GST_BIN(pipeline), rtspsrc, h264depay, h264parse, h264decoder, que, h264sink, NULL);
    g_print("[DEBUG-main]: Elements have been added in the pipeline.\n");

    if (!gst_element_link_many(h264depay, h264parse, h264decoder, que, h264sink, NULL)) {
        g_printerr ("[ERROR-main]: Elements could not be linked.\n");
        gst_object_unref (pipeline);
        return -1;
    } else {
        g_print("[DEBUG-main]: Elements can be linked.\n");
    }

    g_object_set(rtspsrc, "location", "rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov", NULL);

    g_signal_connect(rtspsrc, "pad-added", G_CALLBACK(cb_new_rtspsrc_pad), h264depay);

    g_print("[DEBUG-main]: g_signal_connect() be called.\n");

    /* Start playing */
    ret = gst_element_set_state(pipeline, GST_STATE_PLAYING);

    if (ret == GST_STATE_CHANGE_FAILURE) {
        g_printerr("[ERROR-main]: Unable to set the pipeline to the playing state.\n");
        gst_object_unref(pipeline);
        return -1;
    }

    // Listen to the bus
    bus = gst_element_get_bus(pipeline);
    do {
        msg = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE,
                                         GST_MESSAGE_STATE_CHANGED | GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

        // Parse message
        if (msg != NULL) {
            GError *err;
            gchar *debug_info;

            switch (GST_MESSAGE_TYPE(msg)) {
                case GST_MESSAGE_ERROR:
                    gst_message_parse_error(msg, &err, &debug_info);
                    g_printerr("[ERROR-main]: Error received from element [%s]: [%s]\n", GST_OBJECT_NAME (msg->src), err->message);
                    g_printerr("[ERROR-main]: Debugging information --- [%s]\n", debug_info ? debug_info : "none");
                    g_clear_error(&err);
                    g_free(debug_info);
                    terminate = TRUE;
                    break;
                case GST_MESSAGE_EOS:
                    g_print("[DEBUG-main]: End-Of-Stream reached.\n");
                    terminate = TRUE;
                    break;
                case GST_MESSAGE_STATE_CHANGED:
                    // We are only interested in state-changed messages from the pipeline
                    if (GST_MESSAGE_SRC (msg) == GST_OBJECT (pipeline)) {
                        GstState old_state, new_state, pending_state;
                        gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state);
                        g_print("[DEBUG-main]: Pipeline state changed from [%s] to [%s]:\n",
                                gst_element_state_get_name(old_state), gst_element_state_get_name(new_state));
                    }
                    break;
                default:
                    // We should not reach here
                    g_printerr("[ERROR-main]: Unexpected message received.\n");
                    break;
            }
            gst_message_unref(msg);
        }
    } while(!terminate);

    // Free resources
    gst_object_unref(bus);
    gst_element_set_state(pipeline, GST_STATE_NULL);
    gst_object_unref(pipeline);


    return 0;
}