Maybe a bug, gstreamer Basic tutorial 7: Multithreading and Pad Availability

jetson xavier nx, Jetson NX Developer Kit SD Card Image 4.6

l have a problem like gstreamer tutorial 7
this code :

#include <gst/gst.h>

int main(int argc, char *argv[]) {
  GstElement *pipeline, *audio_source, *tee, *audio_queue, *audio_convert, *audio_resample, *audio_sink;
  GstElement *video_queue, *visual, *video_convert, *video_sink;
  GstBus *bus;
  GstMessage *msg;
  GstPad *tee_audio_pad, *tee_video_pad;
  GstPad *queue_audio_pad, *queue_video_pad;

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

  /* Create the elements */
  audio_source = gst_element_factory_make ("audiotestsrc", "audio_source");
  tee = gst_element_factory_make ("tee", "tee");
  audio_queue = gst_element_factory_make ("queue", "audio_queue");
  audio_convert = gst_element_factory_make ("audioconvert", "audio_convert");
  audio_resample = gst_element_factory_make ("audioresample", "audio_resample");
  audio_sink = gst_element_factory_make ("autoaudiosink", "audio_sink");
  video_queue = gst_element_factory_make ("queue", "video_queue");
  visual = gst_element_factory_make ("wavescope", "visual");
  video_convert = gst_element_factory_make ("videoconvert", "csp");
  video_sink = gst_element_factory_make ("autovideosink", "video_sink");

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

  if (!pipeline || !audio_source || !tee || !audio_queue || !audio_convert || !audio_resample || !audio_sink ||
      !video_queue || !visual || !video_convert || !video_sink) {
    g_printerr ("Not all elements could be created.\n");
    return -1;

  /* Configure elements */
  g_object_set (audio_source, "freq", 215.0f, NULL);
  g_object_set (visual, "shader", 0, "style", 1, NULL);

  /* Link all elements that can be automatically linked because they have "Always" pads */
  gst_bin_add_many (GST_BIN (pipeline), audio_source, tee, audio_queue, audio_convert, audio_resample, audio_sink,
      video_queue, visual, video_convert, video_sink, NULL);
  if (gst_element_link_many (audio_source, tee, NULL) != TRUE ||
      gst_element_link_many (audio_queue, audio_convert, audio_resample, audio_sink, NULL) != TRUE ||
      gst_element_link_many (video_queue, visual, video_convert, video_sink, NULL) != TRUE) {
    g_printerr ("Elements could not be linked.\n");
    gst_object_unref (pipeline);
    return -1;

  /* Manually link the Tee, which has "Request" pads */
  // tee_audio_pad = gst_element_request_pad_sample (tee, "src_%u");
  tee_audio_pad = gst_element_get_request_pad (tee, "src_%u");
  g_print ("Obtained request pad %s for audio branch.\n", gst_pad_get_name (tee_audio_pad));
  queue_audio_pad = gst_element_get_static_pad (audio_queue, "sink");
  tee_video_pad = gst_element_get_request_pad (tee, "src_%u");
  g_print ("Obtained request pad %s for video branch.\n", gst_pad_get_name (tee_video_pad));
  queue_video_pad = gst_element_get_static_pad (video_queue, "sink");
  if (gst_pad_link (tee_audio_pad, queue_audio_pad) != GST_PAD_LINK_OK ||
      gst_pad_link (tee_video_pad, queue_video_pad) != GST_PAD_LINK_OK) {
    g_printerr ("Tee could not be linked.\n");
    gst_object_unref (pipeline);
    return -1;
  gst_object_unref (queue_audio_pad);
  gst_object_unref (queue_video_pad);

  /* Start playing the pipeline */
  gst_element_set_state (pipeline, GST_STATE_PLAYING);

  /* Wait until error or EOS */
  bus = gst_element_get_bus (pipeline);
  msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

  /* Release the request pads from the Tee, and unref them */
  gst_element_release_request_pad (tee, tee_audio_pad);
  gst_element_release_request_pad (tee, tee_video_pad);
  gst_object_unref (tee_audio_pad);
  gst_object_unref (tee_video_pad);

  /* Free resources */
  if (msg != NULL)
    gst_message_unref (msg);
  gst_object_unref (bus);
  gst_element_set_state (pipeline, GST_STATE_NULL);

  gst_object_unref (pipeline);
  return 0;

you can build by :
gcc basic-tutorial-7.c -o basic-tutorial-7 pkg-config --cflags --libs gstreamer-1.0

but i can not get audio wave windows show.
my problem same as this.
you can test this problem?

thanks for your help

Not sure why the sample does not work. It would need other users to share experience.

For using gstreamer on Jetson platforms, we would suggest check gstreamer user guide so that you can use NVIDIA plugins to use hardware acceleration.

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