examples: Add an uridecodebin3 example

Demonstrate a way to select multiple streams

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/880>

tests/examples/decodebin_next/meson.build

@@ -1,4 +1,4 @@
-foreach example : ['decodebin3', 'playbin-test']
+foreach example : ['decodebin3', 'playbin-test', 'uridecodebin3-select-all']
   executable(example, '@0@.c'.format(example),
   c_args : gst_plugins_base_args,
   include_directories: [configinc, libsinc],

tests/examples/decodebin_next/uridecodebin3-select-all.c

@@ -0,0 +1,389 @@
+/* sample application for testing decodebin3
+ *
+ * Copyright (C) 2015 Centricular Ltd
+ *  @author:  Edward Hervey <edward@centricular.com>
+ * Copyright (C) 2020 Seungha Yang <seungha@centricular.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <glib.h>
+#include <glib-object.h>
+#include <glib/gprintf.h>
+#include <gst/gst.h>
+
+/* Global structure */
+
+typedef struct _AppData
+{
+  GMainLoop *mainloop;
+  GstElement *pipeline;
+
+  GstElement *decodebin;
+
+  /* Current collection */
+  GstStreamCollection *collection;
+  guint notify_id;
+} AppData;
+
+static void
+print_tag_foreach (const GstTagList * tags, const gchar * tag,
+    gpointer user_data)
+{
+  GValue val = { 0, };
+  gchar *str;
+  gint depth = GPOINTER_TO_INT (user_data);
+
+  if (!gst_tag_list_copy_value (&val, tags, tag))
+    return;
+
+  if (G_VALUE_HOLDS_STRING (&val))
+    str = g_value_dup_string (&val);
+  else
+    str = gst_value_serialize (&val);
+
+  gst_print ("%*s%s: %s\n", 2 * depth, " ", gst_tag_get_nick (tag), str);
+  g_free (str);
+
+  g_value_unset (&val);
+}
+
+static void
+dump_collection (GstStreamCollection * collection)
+{
+  guint i;
+  GstTagList *tags;
+  GstCaps *caps;
+
+  for (i = 0; i < gst_stream_collection_get_size (collection); i++) {
+    GstStream *stream = gst_stream_collection_get_stream (collection, i);
+    gst_print (" Stream %u type %s flags 0x%x\n", i,
+        gst_stream_type_get_name (gst_stream_get_stream_type (stream)),
+        gst_stream_get_stream_flags (stream));
+    gst_print ("  ID: %s\n", gst_stream_get_stream_id (stream));
+
+    caps = gst_stream_get_caps (stream);
+    if (caps) {
+      gchar *caps_str = gst_caps_to_string (caps);
+      gst_print ("  caps: %s\n", caps_str);
+      g_free (caps_str);
+      gst_caps_unref (caps);
+    }
+
+    tags = gst_stream_get_tags (stream);
+    if (tags) {
+      gst_print ("  tags:\n");
+      gst_tag_list_foreach (tags, print_tag_foreach, GUINT_TO_POINTER (3));
+      gst_tag_list_unref (tags);
+    }
+  }
+}
+
+static gboolean
+activate_all_av_streams (AppData * data)
+{
+  guint i, num_streams;
+  gint num_videos = 0, num_audios = 0, num_texts = 0, num_unknowns = 0;
+  GList *streams = NULL;
+  GstEvent *event;
+  gboolean ret;
+
+  num_streams = gst_stream_collection_get_size (data->collection);
+  for (i = 0; i < num_streams; i++) {
+    GstStream *stream = gst_stream_collection_get_stream (data->collection, i);
+    GstStreamType stype = gst_stream_get_stream_type (stream);
+    if (stype == GST_STREAM_TYPE_VIDEO) {
+      streams = g_list_append (streams,
+          (gchar *) gst_stream_get_stream_id (stream));
+      num_videos++;
+    } else if (stype == GST_STREAM_TYPE_AUDIO) {
+      streams = g_list_append (streams,
+          (gchar *) gst_stream_get_stream_id (stream));
+      num_audios++;
+    } else if (stype == GST_STREAM_TYPE_TEXT) {
+      num_texts++;
+    } else {
+      /* Unknown, container or complex type */
+      num_unknowns++;
+    }
+  }
+
+  gst_println ("Have %d streams (video: %d, audio: %d, text: %d, unknown %d)",
+      num_streams, num_videos, num_audios, num_texts, num_unknowns);
+
+  if (!num_videos && !num_audios) {
+    gst_println ("No AV stream to expose");
+    return FALSE;
+  }
+
+  event = gst_event_new_select_streams (streams);
+  ret = gst_element_send_event (data->decodebin, event);
+
+  gst_println ("Sent select-streams event ret %d", ret);
+
+  return TRUE;
+}
+
+static void
+stream_notify_cb (GstStreamCollection * collection, GstStream * stream,
+    GParamSpec * pspec, guint * val)
+{
+  gst_print ("Got stream-notify from stream %s for %s (collection %p)\n",
+      stream->stream_id, pspec->name, collection);
+  if (g_str_equal (pspec->name, "caps")) {
+    GstCaps *caps = gst_stream_get_caps (stream);
+    gchar *caps_str = gst_caps_to_string (caps);
+    gst_print (" New caps: %s\n", caps_str);
+    g_free (caps_str);
+    gst_caps_unref (caps);
+  }
+}
+
+static GstBusSyncReply
+_on_bus_message (GstBus * bus, GstMessage * message, AppData * data)
+{
+  GstObject *src = GST_MESSAGE_SRC (message);
+  switch (GST_MESSAGE_TYPE (message)) {
+    case GST_MESSAGE_ERROR:{
+      GError *err = NULL;
+      gchar *name = gst_object_get_path_string (GST_MESSAGE_SRC (message));
+      gst_message_parse_error (message, &err, NULL);
+
+      gst_printerr ("ERROR: from element %s: %s\n", name, err->message);
+      g_error_free (err);
+      g_free (name);
+
+      gst_println ("Stopping");
+      g_main_loop_quit (data->mainloop);
+      break;
+    }
+    case GST_MESSAGE_EOS:
+      gst_println ("EOS ! Stopping");
+      g_main_loop_quit (data->mainloop);
+      break;
+    case GST_MESSAGE_STREAM_COLLECTION:
+    {
+      GstStreamCollection *collection = NULL;
+      gst_message_parse_stream_collection (message, &collection);
+      if (collection) {
+        /* Replace stream collection with new one */
+        gst_println ("Got a collection from %s",
+            src ? GST_OBJECT_NAME (src) : "Unknown");
+
+        dump_collection (collection);
+
+        if (data->collection && data->notify_id) {
+          g_signal_handler_disconnect (data->collection, data->notify_id);
+          data->notify_id = 0;
+        }
+
+        gst_object_replace ((GstObject **) & data->collection,
+            (GstObject *) collection);
+
+        if (data->collection) {
+          data->notify_id =
+              g_signal_connect (data->collection, "stream-notify",
+              (GCallback) stream_notify_cb, data);
+        }
+
+        /* Try to expose all audio/video streams */
+        if (!activate_all_av_streams (data))
+          g_main_loop_quit (data->mainloop);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  return GST_BUS_PASS;
+}
+
+static void
+decodebin_pad_added_cb (GstElement * dbin, GstPad * pad, AppData * data)
+{
+  gchar *pad_name = gst_pad_get_name (pad);
+  GstStream *stream;
+  GstStreamType type;
+
+  gst_println ("New pad %s added, try linking with sink", pad_name);
+  g_free (pad_name);
+
+  stream = gst_pad_get_stream (pad);
+  if (!stream) {
+    g_error ("New pad was exposed without GstStream object");
+    g_main_loop_quit (data->mainloop);
+    return;
+  }
+
+  type = gst_stream_get_stream_type (stream);
+
+  switch (type) {
+    case GST_STREAM_TYPE_VIDEO:{
+      GstElement *queue;
+      GstElement *convert;
+      GstElement *sink;
+      GstPad *sinkpad;
+
+      queue = gst_element_factory_make ("queue", NULL);
+      if (!queue) {
+        gst_println ("queue element is unavailable");
+        g_main_loop_quit (data->mainloop);
+        return;
+      }
+      gst_bin_add (GST_BIN_CAST (data->pipeline), queue);
+
+      convert = gst_element_factory_make ("videoconvert", NULL);
+      if (!convert) {
+        gst_println ("videoconvert element is unavailable");
+        goto error;
+      }
+      gst_bin_add (GST_BIN_CAST (data->pipeline), convert);
+
+      sink = gst_element_factory_make ("autovideosink", NULL);
+      if (!sink) {
+        gst_println ("autovideosink element is unavailable");
+        goto error;
+      }
+      gst_bin_add (GST_BIN_CAST (data->pipeline), sink);
+
+      sinkpad = gst_element_get_static_pad (queue, "sink");
+      gst_pad_set_active (sinkpad, TRUE);
+
+      gst_element_link_many (queue, convert, sink, NULL);
+      gst_pad_link (pad, sinkpad);
+      gst_object_unref (sinkpad);
+      gst_element_sync_state_with_parent (queue);
+      gst_element_sync_state_with_parent (convert);
+      gst_element_sync_state_with_parent (sink);
+
+      break;
+    }
+    case GST_STREAM_TYPE_AUDIO:{
+      GstElement *queue;
+      GstElement *convert;
+      GstElement *resample;
+      GstElement *sink;
+      GstPad *sinkpad;
+
+      queue = gst_element_factory_make ("queue", NULL);
+      if (!queue) {
+        gst_println ("queue element is unavailable");
+        goto error;
+      }
+      gst_bin_add (GST_BIN_CAST (data->pipeline), queue);
+
+      convert = gst_element_factory_make ("audioconvert", NULL);
+      if (!convert) {
+        gst_println ("audioconvert element is unavailable");
+        goto error;
+      }
+      gst_bin_add (GST_BIN_CAST (data->pipeline), convert);
+
+      resample = gst_element_factory_make ("audioresample", NULL);
+      if (!resample) {
+        gst_println ("audioresample element is unavailable");
+        goto error;
+      }
+      gst_bin_add (GST_BIN_CAST (data->pipeline), resample);
+
+      sink = gst_element_factory_make ("autoaudiosink", NULL);
+      if (!sink) {
+        gst_println ("autoaudiosink element is unavailable");
+        goto error;
+      }
+
+      gst_bin_add (GST_BIN_CAST (data->pipeline), sink);
+
+      sinkpad = gst_element_get_static_pad (queue, "sink");
+      gst_pad_set_active (sinkpad, TRUE);
+
+      gst_element_link_many (queue, convert, resample, sink, NULL);
+      gst_pad_link (pad, sinkpad);
+      gst_object_unref (sinkpad);
+      gst_element_sync_state_with_parent (queue);
+      gst_element_sync_state_with_parent (convert);
+      gst_element_sync_state_with_parent (resample);
+      gst_element_sync_state_with_parent (sink);
+
+      break;
+    }
+    default:
+      gst_println ("Ignore non video/audio stream %s (0x%x)",
+          gst_stream_type_get_name (type), type);
+      break;
+
+  }
+
+  gst_object_unref (stream);
+  return;
+
+error:
+  gst_object_unref (stream);
+  g_main_loop_quit (data->mainloop);
+
+  return;
+}
+
+int
+main (int argc, gchar ** argv)
+{
+  GstBus *bus;
+  AppData *data;
+
+  gst_init (&argc, &argv);
+
+  if (argc < 2) {
+    gst_print ("Usage: uridecodebin3 URI\n");
+    return 1;
+  }
+
+  data = g_new0 (AppData, 1);
+
+  data->pipeline = gst_pipeline_new ("pipeline");
+  data->decodebin = gst_element_factory_make ("uridecodebin3", NULL);
+
+  g_object_set (data->decodebin, "uri", argv[1], NULL);
+
+  gst_bin_add (GST_BIN_CAST (data->pipeline), data->decodebin);
+
+  g_signal_connect (data->decodebin, "pad-added",
+      (GCallback) decodebin_pad_added_cb, data);
+  data->mainloop = g_main_loop_new (NULL, FALSE);
+
+  /* Put a bus handler */
+  bus = gst_pipeline_get_bus (GST_PIPELINE (data->pipeline));
+  gst_bus_set_sync_handler (bus, (GstBusSyncHandler) _on_bus_message, data,
+      NULL);
+
+  /* Start pipeline */
+  gst_element_set_state (data->pipeline, GST_STATE_PLAYING);
+  g_main_loop_run (data->mainloop);
+
+  gst_element_set_state (data->pipeline, GST_STATE_NULL);
+
+  gst_object_unref (data->pipeline);
+  gst_clear_object (&data->collection);
+  gst_object_unref (bus);
+
+  g_free (data);
+
+  return 0;
+}