gstreamer/tests/examples/queue/queue.c

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

/* This example uses the queue element to create a buffer between 2 elements.
 * The scheduler automatically uses 2 threads, 1 to feed and another to consume
 * data from the queue buffer
 */

/* Event loop to listen to events posted on the GstBus from the pipeline. Exits
 * on EOS or ERROR events
 */
static void
event_loop (GstElement * pipe)
{
  GstBus *bus;
  GstMessage *message = NULL;
  gboolean running = TRUE;

  bus = gst_element_get_bus (GST_ELEMENT (pipe));

  while (running) {
    message = gst_bus_poll (bus, GST_MESSAGE_ANY, -1);

    g_assert (message != NULL);

    switch (message->type) {
      case GST_MESSAGE_EOS:
        running = FALSE;
        break;
      case GST_MESSAGE_WARNING:{
        GError *gerror;
        gchar *debug;

        gst_message_parse_warning (message, &gerror, &debug);
        gst_object_default_error (GST_MESSAGE_SRC (message), gerror, debug);
        g_error_free (gerror);
        g_free (debug);
        break;
      }
      case GST_MESSAGE_ERROR:{
        GError *gerror;
        gchar *debug;

        gst_message_parse_error (message, &gerror, &debug);
        gst_object_default_error (GST_MESSAGE_SRC (message), gerror, debug);
        g_error_free (gerror);
        g_free (debug);
        running = FALSE;
        break;
      }
      default:
        break;
    }
    gst_message_unref (message);
  }
  gst_object_unref (bus);
}

int
main (int argc, char *argv[])
{
  GstElement *filesrc, *audiosink, *decode, *queue;
  GstElement *pipeline;

  gst_init (&argc, &argv);

  if (argc != 2) {
    g_print ("usage: %s <filename>\n", argv[0]);
    exit (-1);
  }

  /* create a new pipeline to hold the elements */
  pipeline = gst_pipeline_new ("pipeline");
  g_assert (pipeline != NULL);

  /* create a disk reader */
  filesrc = gst_element_factory_make ("filesrc", "disk_source");
  g_assert (filesrc != NULL);
  g_object_set (G_OBJECT (filesrc), "location", argv[1], NULL);

  decode = gst_element_factory_make ("mad", "decode");
  g_assert (decode != NULL);

  queue = gst_element_factory_make ("queue", "queue");
  g_assert (queue != NULL);

  /* and an audio sink */
  audiosink = gst_element_factory_make ("alsasink", "play_audio");
  g_assert (audiosink != NULL);

  /* add objects to the main pipeline */
  gst_bin_add_many (GST_BIN (pipeline), filesrc, decode, queue, audiosink,
      NULL);

  gst_element_link_many (filesrc, decode, queue, audiosink, NULL);

  /* start playing */
  gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_PLAYING);

  /* Listen for EOS */
  event_loop (pipeline);

  gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_NULL);

  exit (0);
}