我想问一下我正在使用 Gstreamer 使用 fpsdisplaysink 在 Linux 终端上显示播放视频的 FPS（帧率）。但现在，我想在屏幕上显示 FPS（通过韦斯顿背景下的 Wayland 客户端）。任何人都可以帮忙吗？谢谢。
编辑：下面是用 C 编写的源 gstreamer。
#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;
}
我尝试了上面的代码，但它似乎不起作用。