是否有 C++ 的简单 GStreamer 示例？

Question

I am looking for simple example for GStreamer that uses Video-Streaming...

I would like to create a simple example (showing a video-output) incl. compilation instructions.

Answer 1

This will be the source code of a GStreamer pipeline videotestsrc ! autovideosink videotestsrc ! autovideosink . It will show a nice video output...

Prerequisites Make sure you have GStreamer and gcc installed.

Add the following source code to helloworld.c

#include <gst/gst.h>
#include <glib.h>


static gboolean bus_call (GstBus *bus, GstMessage *msg, gpointer data)
{
  GMainLoop *loop = (GMainLoop *) data;

  switch (GST_MESSAGE_TYPE (msg)) {

    case GST_MESSAGE_EOS:
      g_print ("End of stream\n");
      g_main_loop_quit (loop);
      break;

    case GST_MESSAGE_ERROR: {
      gchar  *debug;
      GError *error;

      gst_message_parse_error (msg, &error, &debug);
      g_free (debug);

      g_printerr ("Error: %s\n", error->message);
      g_error_free (error);

      g_main_loop_quit (loop);
      break;
    }
    default:
      break;
  }

  return TRUE;
}



int main (int argc, char *argv[])
{
  GMainLoop *loop;

  GstElement *pipeline, *videotestsrcm, *autovideosinkm;
  GstBus *bus;
  guint bus_watch_id;

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

  loop = g_main_loop_new (NULL, FALSE);


  /* Create gstreamer elements */
  pipeline = gst_pipeline_new ("videotest-pipeline");
  videotestsrcm   = gst_element_factory_make ("videotestsrc", "testsource");
  autovideosinkm = gst_element_factory_make ("autovideosink", "videosink");

  if (!pipeline || !videotestsrcm || !autovideosinkm) {
    g_printerr ("One element could not be created. Exiting.\n");
    return -1;
  }

  /* Set up the pipeline */

  /* we add a message handler */
  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
  bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);
  gst_object_unref (bus);


  /* we add all elements into the pipeline */
  gst_bin_add_many (GST_BIN (pipeline),
                    videotestsrcm, autovideosinkm, NULL);

  /* we link the elements together */
  /* videotestsrcm -> autovideosinkm */
  gst_element_link (videotestsrcm, autovideosinkm);


  /* Set the pipeline to "playing" state*/
  g_print ("Now set pipeline in state playing");
  gst_element_set_state (pipeline, GST_STATE_PLAYING);


  /* Iterate */
  g_print ("Running...\n");
  g_main_loop_run (loop);


  /* Out of the main loop, clean up nicely */
  g_print ("Returned, stopping playback\n");
  gst_element_set_state (pipeline, GST_STATE_NULL);

  g_print ("Deleting pipeline\n");
  gst_object_unref (GST_OBJECT (pipeline));
  g_source_remove (bus_watch_id);
  g_main_loop_unref (loop);

  return 0;
}

Compile it

gcc -Wall helloworld.c -o helloworld $(pkg-config --cflags --libs gstreamer-1.0)

Run it

./helloworld