Отображение FPS на клиенте wayland в Linux

Я хотел бы спросить, что я использую Gstreamer для отображения FPS (частоты кадров) воспроизводимого видео на терминале Linux с помощью fpsdisplaysink. Но теперь я хочу отобразить FPS на экране (через клиент Wayland на фоне Weston). Кто-нибудь может помочь? Спасибо.

РЕДАКТИРОВАТЬ: Ниже приведен исходный код gstreamer, написанный на C.

#include <gst/gst.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wayland-client.h>
#include <wayland-egl.h>
#include <wayland-client-protocol.h>
#include <cairo.h>

#include "helpers.h"

#define INPUT_FILE "/home/root/videos/vga1.h264"
#define POSITION_X 100
#define POSITION_Y 100
#define DELAY_VALUE 1000000

static const unsigned WIDTH = 320;
static const unsigned HEIGHT = 200;
static const unsigned CURSOR_WIDTH = 100;
static const unsigned CURSOR_HEIGHT = 59;
static const int32_t CURSOR_HOT_SPOT_X = 10;
static const int32_t CURSOR_HOT_SPOT_Y = 35;
static char prv_time_str[25] = {0,};
static volatile int fps_counter = 0;
static char str_fps[10] = "";
static time_t timer;
static char time_str[25];
static struct tm* tm_info;
int ignored_first = 0;
static GstElement *overlay;

static GstPadProbeReturn
cb_have_data (GstPad          *pad,
              GstPadProbeInfo *info,
              gpointer         user_data)
{
    time(&timer);
    tm_info = localtime(&timer);
    strftime(time_str, 25, "%Y:%m:%d%H:%M:%S\n", tm_info);

    fps_counter++;
    if (!strlen(prv_time_str))
        strcpy(prv_time_str, time_str);
    if (strcmp(prv_time_str, time_str)) {
        if (ignored_first) {
            sprintf(str_fps, "FPS: %d", fps_counter);
            g_object_set (G_OBJECT (overlay), "text", str_fps, NULL);
            g_print("fps: %d\n", fps_counter);
        }
        ignored_first = 1;
        fps_counter = 0;
    }
    strcpy(prv_time_str, time_str);

    return GST_PAD_PROBE_OK;
}

int
main (int argc, char *argv[])
{
  GstElement *pipeline, *source, *parser, *decoder, *sink;
  GstBus *bus;
  GstMessage *msg;
  GstPad *pad;
  gchar *fps_msg;
  guint delay_show_FPS = 0;

  const gchar *input_file = INPUT_FILE;

  /* Initialization */
  gst_init (&argc, &argv);

  /* Create gstreamer elements */
  pipeline = gst_pipeline_new ("video-play");
  source = gst_element_factory_make ("filesrc", "file-source");
  parser = gst_element_factory_make ("h264parse", "h264-parser");
  decoder = gst_element_factory_make ("omxh264dec", "h264-decoder");
  sink = gst_element_factory_make ("waylandsink", "video-output");
  overlay = gst_element_factory_make ("textoverlay", "overlay");

  if (!pipeline || !source || !parser || !decoder || !sink || !overlay ) {
    g_printerr ("One element could not be created. Exiting.\n");
    return -1;
  }

  /* Set input video file for source element */
  g_object_set (G_OBJECT (source), "location", input_file, NULL);

  /* Set position for displaying (100, 100) */
  g_object_set (G_OBJECT (sink), "position-x", POSITION_X, "position-y", POSITION_Y, NULL);

  /* Add textoverlay element to display text in foreground */
  g_object_set (G_OBJECT (overlay), "font-desc", "Sans, 72", NULL);

  /* Add all elements into the pipeline */
  /* pipeline---[ file-source + h264-parser + h264-decoder + video-output ] */
  gst_bin_add_many (GST_BIN (pipeline), source, parser, decoder, overlay, sink, NULL);

  /* Link the elements together */
  /* file-source -> h264-parser -> h264-decoder -> video-output */
  if (gst_element_link_many (source, parser, decoder, overlay, sink, NULL) != TRUE) {
    g_printerr ("Elements could not be linked.\n");
    gst_object_unref (pipeline);
    return -1;
  }

  /* Retrieve a pad from waylandsink */
  pad = gst_element_get_static_pad (sink, "sink");

  /* Add buffer probe from within event probe callback of having data */
  gst_pad_add_probe (pad, GST_PAD_PROBE_TYPE_BUFFER, (GstPadProbeCallback)cb_have_data, NULL, NULL);

  gst_object_unref (pad);

  /* Set the pipeline to "playing" state */
  g_print ("Now playing: %s\n", input_file);
  if (gst_element_set_state (pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
    g_printerr ("Unable to set the pipeline to the playing state.\n");
    gst_object_unref (pipeline);
    return -1;
  }

  g_print ("Running...\n");

  /* Wait until error or EOS */
  bus = gst_element_get_bus (pipeline);
  while(1) {
    msg = gst_bus_pop (bus);

    /* Loop forever until a matching message was posted 
       on the bus (GST_MESSAGE_ERROR or GST_MESSAGE_EOS). */
    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 received from element %s: %s.\n",
            GST_OBJECT_NAME (msg->src), err->message);
          g_printerr ("Debugging information: %s.\n",
            debug_info ? debug_info : "none");
          g_clear_error (&err);
          g_free (debug_info);
          goto stop_pipeline;
        case GST_MESSAGE_EOS:
          g_print ("End-Of-Stream reached.\n");
          goto stop_pipeline;
        default:
          /* do nothing */
          break;
      }
      gst_message_unref (msg);
    }
  }

  /* Free resources and change state to NULL */
stop_pipeline:
  gst_object_unref (bus);
  g_print ("Returned, stopping playback...\n");
  gst_element_set_state (pipeline, GST_STATE_NULL);
  g_print ("Freeing pipeline...\n");
  gst_object_unref (GST_OBJECT (pipeline));
  g_print ("Completed. Goodbye!\n");
  return EXIT_SUCCESS;
}

Я пробовал приведенный выше код, но он не работал.