Playsink

The playsink element is a powerful sink element. It has request pads for raw decoded audio, video and text and it will configure itself to play the media streams. It has the following features:

Below is an example of how you can use playsink. We use a uridecodebin element to decode into raw audio and video streams which we then link to the playsink request pads. We only link the first audio and video pads, you could use an input-selector to link all pads.



#include <gst/gst.h>


[.. my_bus_callback goes here ..]





GstElement *pipeline, *sink;

static void
cb_pad_added (GstElement *dec,
	      GstPad     *pad,
	      gpointer    data)
{
  GstCaps *caps;
  GstStructure *str;
  const gchar *name;
  GstPadTemplate *templ;
  GstElementClass *klass;

  /* check media type */
  caps = gst_pad_query_caps (pad, NULL);
  str = gst_caps_get_structure (caps, 0);
  name = gst_structure_get_name (str);

  klass = GST_ELEMENT_GET_CLASS (sink);

  if (g_str_has_prefix (name, "audio")) {
    templ = gst_element_class_get_pad_template (klass, "audio_sink");
  } else if (g_str_has_prefix (name, "video")) {
    templ = gst_element_class_get_pad_template (klass, "video_sink");
  } else if (g_str_has_prefix (name, "text")) {
    templ = gst_element_class_get_pad_template (klass, "text_sink");
  } else {
    templ = NULL;
  }

  if (templ) {
    GstPad *sinkpad;

    sinkpad = gst_element_request_pad (sink, templ, NULL, NULL);

    if (!gst_pad_is_linked (sinkpad))
      gst_pad_link (pad, sinkpad);

    gst_object_unref (sinkpad);
  }
}

gint
main (gint   argc,
      gchar *argv[])
{
  GMainLoop *loop;
  GstElement *dec;
  GstBus *bus;

  /* init GStreamer */
  gst_init (&argc, &argv);
  loop = g_main_loop_new (NULL, FALSE);

  /* make sure we have input */
  if (argc != 2) {
    g_print ("Usage: %s <uri>\n", argv[0]);
    return -1;
  }

  /* setup */
  pipeline = gst_pipeline_new ("pipeline");

  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
  gst_bus_add_watch (bus, my_bus_callback, loop);
  gst_object_unref (bus);

  dec = gst_element_factory_make ("uridecodebin", "source");
  g_object_set (G_OBJECT (dec), "uri", argv[1], NULL);
  g_signal_connect (dec, "pad-added", G_CALLBACK (cb_pad_added), NULL);

  /* create audio output */
  sink = gst_element_factory_make ("playsink", "sink");
  gst_util_set_object_arg (G_OBJECT (sink), "flags",  
      "soft-colorbalance+soft-volume+vis+text+audio+video");
  gst_bin_add_many (GST_BIN (pipeline), dec, sink, NULL);

  /* run */
  gst_element_set_state (pipeline, GST_STATE_PLAYING);
  g_main_loop_run (loop);

  /* cleanup */
  gst_element_set_state (pipeline, GST_STATE_NULL);
  gst_object_unref (GST_OBJECT (pipeline));

  return 0;
}


    

This example will show audio and video depending on what you give it. Try this example on an audio file and you will see that it shows visualizations. You can change the visualization at runtime by changing the vis-plugin property.