Add metadata reading example that loops over a list of filenames, dumping any tags found.

Original commit message from CVS:
* configure.ac:
* examples/Makefile.am:
* examples/metadata/Makefile.am:
* examples/metadata/read-metadata.c: (message_loop),
(have_pad_handler), (make_pipeline), (print_tag), (main):
Add metadata reading example that loops over a list of filenames,
dumping any tags found.

* gst/gstbus.c: (gst_bus_dispose):
* gst/gstelement.c: (gst_element_dispose):
Release a few potentially-held references in dispose.

ChangeLog

@@ -1,3 +1,17 @@
+2005-08-26  Jan Schmidt  <thaytan@mad.scientist.com>
+
+	* configure.ac:
+	* examples/Makefile.am:
+	* examples/metadata/Makefile.am:
+	* examples/metadata/read-metadata.c: (message_loop),
+	(have_pad_handler), (make_pipeline), (print_tag), (main):
+	  Add metadata reading example that loops over a list of filenames,
+	  dumping any tags found.
+
+	* gst/gstbus.c: (gst_bus_dispose):
+	* gst/gstelement.c: (gst_element_dispose):
+	  Release a few potentially-held references in dispose.
+
 2005-08-26  Stefan Kost  <ensonic@users.sf.net>
 
 	* docs/gst/tmpl/gstminiobject.sgml:

configure.ac

@@ -668,6 +668,7 @@ examples/helloworld/Makefile
 examples/launch/Makefile
 examples/manual/Makefile
 examples/mixer/Makefile
+examples/metadata/Makefile
 examples/pingpong/Makefile
 examples/plugins/Makefile
 examples/pwg/Makefile

examples/Makefile.am

@@ -11,6 +11,7 @@ dirs = \
 	thread				\
 	plugins				\
 	mixer				\
+	metadata                        \
 	controller			\
 	cutter				\
 	pingpong			\

examples/metadata/Makefile.am

@@ -0,0 +1,4 @@
+noinst_PROGRAMS = read-metadata
+
+read_metadata_LDADD = $(GST_OBJ_LIBS)
+read_metadata_CFLAGS = $(GST_OBJ_CFLAGS)

examples/metadata/read-metadata.c

@@ -0,0 +1,249 @@
+/* GStreamer
+ * Copyright (C) 2003 Thomas Vander Stichele <thomas@apestaart.org>
+ *               2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
+ *               2005 Andy Wingo <wingo@pobox.com>
+ *               2005 Jan Schmidt <thaytan@mad.scientist.com>
+ *
+ * gst-metadata.c: Use GStreamer to display metadata within files.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+#include <locale.h>
+#include <gst/gst.h>
+
+char *filename = NULL;
+GstElement *pipeline = NULL;
+GstElement *source = NULL;
+
+#define NEW_PIPE_PER_FILE
+
+static void
+message_loop (GstElement * element, GstTagList ** tags)
+{
+  GstBus *bus;
+  gboolean done = FALSE;
+
+  bus = gst_element_get_bus (element);
+  g_return_if_fail (bus != NULL);
+  g_return_if_fail (tags != NULL);
+
+  while (!done) {
+    GstMessage *message;
+    GstMessageType revent;
+
+    revent = gst_bus_poll (bus, GST_MESSAGE_ANY, -1);
+    if (revent == GST_MESSAGE_UNKNOWN) {
+      /* Messages ended */
+      gst_object_unref (bus);
+      return;
+    }
+
+    message = gst_bus_pop (bus);
+    if (message == NULL)
+      continue;
+
+    switch (GST_MESSAGE_TYPE (message)) {
+      case GST_MESSAGE_EOS:
+      case GST_MESSAGE_ERROR:
+        done = TRUE;
+        break;
+      case GST_MESSAGE_TAG:
+      {
+        GstTagList *new_tags;
+
+        gst_message_parse_tag (message, &new_tags);
+        if (tags) {
+          if (*tags)
+            *tags =
+                gst_tag_list_merge (*tags, new_tags, GST_TAG_MERGE_KEEP_ALL);
+          else
+            *tags = new_tags;
+        } else {
+          GST_WARNING ("Failed to extract tags list from message");
+        }
+        break;
+      }
+      case GST_MESSAGE_APPLICATION:
+      {
+        const GstStructure *s = gst_message_get_structure (message);
+
+        /* Application specific message used to mark end point */
+        if (strcmp (gst_structure_get_name (s), "gst-metadata-mark") == 0)
+          done = TRUE;
+        break;
+      }
+      default:
+        break;
+    }
+    gst_message_unref (message);
+  }
+  gst_object_unref (bus);
+}
+
+void
+have_pad_handler (GstElement * decodebin, GstPad * pad, gboolean last,
+    GstElement * sink)
+{
+  GST_DEBUG ("New pad %" GST_PTR_FORMAT " - attempting link", pad);
+
+  gst_pad_link (pad, gst_element_get_pad (sink, "sink"));
+}
+
+static void
+make_pipeline ()
+{
+  GstElement *decodebin, *fakesink;
+
+  if (pipeline != NULL)
+    gst_object_unref (pipeline);
+
+  pipeline = gst_pipeline_new (NULL);
+
+  g_object_set (G_OBJECT (pipeline), "play-timeout",
+      (GstClockTime) 5 * GST_SECOND, NULL);
+
+  source = gst_element_factory_make ("filesrc", "source");
+  g_assert (GST_IS_ELEMENT (source));
+  decodebin = gst_element_factory_make ("decodebin", "decodebin");
+  g_assert (GST_IS_ELEMENT (decodebin));
+  fakesink = gst_element_factory_make ("fakesink", "fakesink");
+  g_assert (GST_IS_ELEMENT (fakesink));
+
+  gst_bin_add_many (GST_BIN (pipeline), source, decodebin, fakesink, NULL);
+  gst_element_link (source, decodebin);
+
+  /* Listen for pads from decodebin */
+  g_signal_connect (G_OBJECT (decodebin), "new-decoded-pad",
+      G_CALLBACK (have_pad_handler), fakesink);
+}
+
+static void
+print_tag (const GstTagList * list, const gchar * tag, gpointer unused)
+{
+  gint i, count;
+
+  count = gst_tag_list_get_tag_size (list, tag);
+
+  for (i = 0; i < count; i++) {
+    gchar *str;
+
+    if (gst_tag_get_type (tag) == G_TYPE_STRING) {
+      if (!gst_tag_list_get_string_index (list, tag, i, &str))
+        g_assert_not_reached ();
+    } else {
+      str =
+          g_strdup_value_contents (gst_tag_list_get_value_index (list, tag, i));
+    }
+
+    if (i == 0) {
+      g_print ("  %15s: %s\n", gst_tag_get_nick (tag), str);
+    } else {
+      g_print ("                 : %s\n", str);
+    }
+
+    g_free (str);
+  }
+}
+
+int
+main (int argc, char *argv[])
+{
+  guint i = 1;
+
+  setlocale (LC_ALL, "");
+
+  gst_init (&argc, &argv);
+
+  if (argc < 2) {
+    g_print ("Please give filenames to read metadata from\n\n");
+    return 1;
+  }
+
+  make_pipeline ();
+  while (i < argc) {
+    GstElementStateReturn sret;
+    GstElementState state;
+
+    filename = argv[i];
+    g_object_set (source, "location", filename, NULL);
+
+    GST_DEBUG ("Starting reading for %s", filename);
+
+    /* Decodebin will only commit to PAUSED if it actually finds a type;
+     * otherwise the state change fails */
+    sret = gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_PAUSED);
+
+    if (GST_STATE_ASYNC == sret) {
+      if (GST_STATE_FAILURE ==
+          gst_element_get_state (GST_ELEMENT (pipeline), &state, NULL, NULL)) {
+        g_print ("State change failed. Aborting");
+        break;
+      }
+    } else if (sret != GST_STATE_SUCCESS) {
+      g_print ("%s - Could not read file\n", argv[i]);
+    } else {
+      GstTagList *tags = NULL;
+      GstBus *bus;
+
+      /* Send message on the bus to mark end point of preroll. */
+      bus = gst_element_get_bus (GST_ELEMENT (pipeline));
+      if (bus) {
+        gst_bus_post (bus,
+            gst_message_new_application (NULL,
+                gst_structure_new ("gst-metadata-mark", NULL)));
+        gst_object_unref (bus);
+      }
+
+      message_loop (GST_ELEMENT (pipeline), &tags);
+
+      if (tags) {
+        g_print ("Metadata for %s:\n", argv[i]);
+        gst_tag_list_foreach (tags, print_tag, NULL);
+        gst_tag_list_free (tags);
+        tags = NULL;
+      } else
+        g_print ("No metadata found for %s\n", argv[i]);
+
+      sret = gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_NULL);
+      if (GST_STATE_ASYNC == sret) {
+        if (GST_STATE_FAILURE ==
+            gst_element_get_state (GST_ELEMENT (pipeline), &state, NULL, NULL))
+        {
+          g_print ("State change failed. Aborting");
+          break;
+        }
+      }
+    }
+
+    i++;
+
+#ifdef NEW_PIPE_PER_FILE
+    make_pipeline ();
+#endif
+  }
+
+  if (pipeline)
+    gst_object_unref (pipeline);
+  return 0;
+}

gst/gstbus.c

@@ -113,7 +113,14 @@ gst_bus_dispose (GObject * object)
   bus = GST_BUS (object);
 
   if (bus->queue) {
+    GstMessage *message;
+
     g_mutex_lock (bus->queue_lock);
+    do {
+      message = g_queue_pop_head (bus->queue);
+      if (message)
+        gst_message_unref (message);
+    } while (message != NULL);
     g_queue_free (bus->queue);
     bus->queue = NULL;
     g_mutex_unlock (bus->queue_lock);

gst/gstelement.c

@@ -2064,6 +2064,7 @@ gst_element_dispose (GObject * object)
 
   GST_LOCK (element);
   gst_object_replace ((GstObject **) & element->clock, NULL);
+  gst_object_replace ((GstObject **) & element->bus, NULL);
   GST_UNLOCK (element);
 
   GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose parent");

tests/old/examples/Makefile.am

@@ -11,6 +11,7 @@ dirs = \
 	thread				\
 	plugins				\
 	mixer				\
+	metadata                        \
 	controller			\
 	cutter				\
 	pingpong			\

tests/old/examples/metadata/Makefile.am

@@ -0,0 +1,4 @@
+noinst_PROGRAMS = read-metadata
+
+read_metadata_LDADD = $(GST_OBJ_LIBS)
+read_metadata_CFLAGS = $(GST_OBJ_CFLAGS)

tests/old/examples/metadata/read-metadata.c

@@ -0,0 +1,249 @@
+/* GStreamer
+ * Copyright (C) 2003 Thomas Vander Stichele <thomas@apestaart.org>
+ *               2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
+ *               2005 Andy Wingo <wingo@pobox.com>
+ *               2005 Jan Schmidt <thaytan@mad.scientist.com>
+ *
+ * gst-metadata.c: Use GStreamer to display metadata within files.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+#include <locale.h>
+#include <gst/gst.h>
+
+char *filename = NULL;
+GstElement *pipeline = NULL;
+GstElement *source = NULL;
+
+#define NEW_PIPE_PER_FILE
+
+static void
+message_loop (GstElement * element, GstTagList ** tags)
+{
+  GstBus *bus;
+  gboolean done = FALSE;
+
+  bus = gst_element_get_bus (element);
+  g_return_if_fail (bus != NULL);
+  g_return_if_fail (tags != NULL);
+
+  while (!done) {
+    GstMessage *message;
+    GstMessageType revent;
+
+    revent = gst_bus_poll (bus, GST_MESSAGE_ANY, -1);
+    if (revent == GST_MESSAGE_UNKNOWN) {
+      /* Messages ended */
+      gst_object_unref (bus);
+      return;
+    }
+
+    message = gst_bus_pop (bus);
+    if (message == NULL)
+      continue;
+
+    switch (GST_MESSAGE_TYPE (message)) {
+      case GST_MESSAGE_EOS:
+      case GST_MESSAGE_ERROR:
+        done = TRUE;
+        break;
+      case GST_MESSAGE_TAG:
+      {
+        GstTagList *new_tags;
+
+        gst_message_parse_tag (message, &new_tags);
+        if (tags) {
+          if (*tags)
+            *tags =
+                gst_tag_list_merge (*tags, new_tags, GST_TAG_MERGE_KEEP_ALL);
+          else
+            *tags = new_tags;
+        } else {
+          GST_WARNING ("Failed to extract tags list from message");
+        }
+        break;
+      }
+      case GST_MESSAGE_APPLICATION:
+      {
+        const GstStructure *s = gst_message_get_structure (message);
+
+        /* Application specific message used to mark end point */
+        if (strcmp (gst_structure_get_name (s), "gst-metadata-mark") == 0)
+          done = TRUE;
+        break;
+      }
+      default:
+        break;
+    }
+    gst_message_unref (message);
+  }
+  gst_object_unref (bus);
+}
+
+void
+have_pad_handler (GstElement * decodebin, GstPad * pad, gboolean last,
+    GstElement * sink)
+{
+  GST_DEBUG ("New pad %" GST_PTR_FORMAT " - attempting link", pad);
+
+  gst_pad_link (pad, gst_element_get_pad (sink, "sink"));
+}
+
+static void
+make_pipeline ()
+{
+  GstElement *decodebin, *fakesink;
+
+  if (pipeline != NULL)
+    gst_object_unref (pipeline);
+
+  pipeline = gst_pipeline_new (NULL);
+
+  g_object_set (G_OBJECT (pipeline), "play-timeout",
+      (GstClockTime) 5 * GST_SECOND, NULL);
+
+  source = gst_element_factory_make ("filesrc", "source");
+  g_assert (GST_IS_ELEMENT (source));
+  decodebin = gst_element_factory_make ("decodebin", "decodebin");
+  g_assert (GST_IS_ELEMENT (decodebin));
+  fakesink = gst_element_factory_make ("fakesink", "fakesink");
+  g_assert (GST_IS_ELEMENT (fakesink));
+
+  gst_bin_add_many (GST_BIN (pipeline), source, decodebin, fakesink, NULL);
+  gst_element_link (source, decodebin);
+
+  /* Listen for pads from decodebin */
+  g_signal_connect (G_OBJECT (decodebin), "new-decoded-pad",
+      G_CALLBACK (have_pad_handler), fakesink);
+}
+
+static void
+print_tag (const GstTagList * list, const gchar * tag, gpointer unused)
+{
+  gint i, count;
+
+  count = gst_tag_list_get_tag_size (list, tag);
+
+  for (i = 0; i < count; i++) {
+    gchar *str;
+
+    if (gst_tag_get_type (tag) == G_TYPE_STRING) {
+      if (!gst_tag_list_get_string_index (list, tag, i, &str))
+        g_assert_not_reached ();
+    } else {
+      str =
+          g_strdup_value_contents (gst_tag_list_get_value_index (list, tag, i));
+    }
+
+    if (i == 0) {
+      g_print ("  %15s: %s\n", gst_tag_get_nick (tag), str);
+    } else {
+      g_print ("                 : %s\n", str);
+    }
+
+    g_free (str);
+  }
+}
+
+int
+main (int argc, char *argv[])
+{
+  guint i = 1;
+
+  setlocale (LC_ALL, "");
+
+  gst_init (&argc, &argv);
+
+  if (argc < 2) {
+    g_print ("Please give filenames to read metadata from\n\n");
+    return 1;
+  }
+
+  make_pipeline ();
+  while (i < argc) {
+    GstElementStateReturn sret;
+    GstElementState state;
+
+    filename = argv[i];
+    g_object_set (source, "location", filename, NULL);
+
+    GST_DEBUG ("Starting reading for %s", filename);
+
+    /* Decodebin will only commit to PAUSED if it actually finds a type;
+     * otherwise the state change fails */
+    sret = gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_PAUSED);
+
+    if (GST_STATE_ASYNC == sret) {
+      if (GST_STATE_FAILURE ==
+          gst_element_get_state (GST_ELEMENT (pipeline), &state, NULL, NULL)) {
+        g_print ("State change failed. Aborting");
+        break;
+      }
+    } else if (sret != GST_STATE_SUCCESS) {
+      g_print ("%s - Could not read file\n", argv[i]);
+    } else {
+      GstTagList *tags = NULL;
+      GstBus *bus;
+
+      /* Send message on the bus to mark end point of preroll. */
+      bus = gst_element_get_bus (GST_ELEMENT (pipeline));
+      if (bus) {
+        gst_bus_post (bus,
+            gst_message_new_application (NULL,
+                gst_structure_new ("gst-metadata-mark", NULL)));
+        gst_object_unref (bus);
+      }
+
+      message_loop (GST_ELEMENT (pipeline), &tags);
+
+      if (tags) {
+        g_print ("Metadata for %s:\n", argv[i]);
+        gst_tag_list_foreach (tags, print_tag, NULL);
+        gst_tag_list_free (tags);
+        tags = NULL;
+      } else
+        g_print ("No metadata found for %s\n", argv[i]);
+
+      sret = gst_element_set_state (GST_ELEMENT (pipeline), GST_STATE_NULL);
+      if (GST_STATE_ASYNC == sret) {
+        if (GST_STATE_FAILURE ==
+            gst_element_get_state (GST_ELEMENT (pipeline), &state, NULL, NULL))
+        {
+          g_print ("State change failed. Aborting");
+          break;
+        }
+      }
+    }
+
+    i++;
+
+#ifdef NEW_PIPE_PER_FILE
+    make_pipeline ();
+#endif
+  }
+
+  if (pipeline)
+    gst_object_unref (pipeline);
+  return 0;
+}