playbin/uridecodebin: Emit source-setup signal early before doing the scheduling query

Some elements will require the source to be set up properly before the
scheduling query returns useful results, e.g. appsrc and giostreamsrc.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1241>

gst/playback/gstplaybin2.c

@@ -332,6 +332,7 @@ struct _GstSourceGroup
   gulong pad_removed_id;
   gulong no_more_pads_id;
   gulong notify_source_id;
+  gulong source_setup_id;
   gulong drained_id;
   gulong autoplug_factories_id;
   gulong autoplug_select_id;
@@ -5254,9 +5255,17 @@ notify_source_cb (GstElement * uridecodebin, GParamSpec * pspec,
   GST_OBJECT_UNLOCK (playbin);
 
   g_object_notify (G_OBJECT (playbin), "source");
+}
 
-  g_signal_emit (playbin, gst_play_bin_signals[SIGNAL_SOURCE_SETUP],
+static void
-      0, playbin->source);
+source_setup_cb (GstElement * uridecodebin, GstElement * source,
+    GstSourceGroup * group)
+{
+  GstPlayBin *playbin;
+
+  playbin = group->playbin;
+
+  g_signal_emit (playbin, gst_play_bin_signals[SIGNAL_SOURCE_SETUP], 0, source);
 }
 
 /* must be called with the group lock */
@@ -5394,6 +5403,8 @@ activate_group (GstPlayBin * playbin, GstSourceGroup * group, GstState target)
       G_CALLBACK (no_more_pads_cb), group);
   group->notify_source_id = g_signal_connect (uridecodebin, "notify::source",
       G_CALLBACK (notify_source_cb), group);
+  group->source_setup_id = g_signal_connect (uridecodebin, "source-setup",
+      G_CALLBACK (source_setup_cb), group);
 
   /* we have 1 pending no-more-pads */
   group->pending = 1;
@@ -5573,6 +5584,7 @@ error_cleanup:
       REMOVE_SIGNAL (group->uridecodebin, group->pad_removed_id);
       REMOVE_SIGNAL (group->uridecodebin, group->no_more_pads_id);
       REMOVE_SIGNAL (group->uridecodebin, group->notify_source_id);
+      REMOVE_SIGNAL (group->uridecodebin, group->source_setup_id);
       REMOVE_SIGNAL (group->uridecodebin, group->drained_id);
       REMOVE_SIGNAL (group->uridecodebin, group->autoplug_factories_id);
       REMOVE_SIGNAL (group->uridecodebin, group->autoplug_select_id);
@@ -5661,6 +5673,7 @@ deactivate_group (GstPlayBin * playbin, GstSourceGroup * group)
     REMOVE_SIGNAL (group->uridecodebin, group->pad_removed_id);
     REMOVE_SIGNAL (group->uridecodebin, group->no_more_pads_id);
     REMOVE_SIGNAL (group->uridecodebin, group->notify_source_id);
+    REMOVE_SIGNAL (group->uridecodebin, group->source_setup_id);
     REMOVE_SIGNAL (group->uridecodebin, group->drained_id);
     REMOVE_SIGNAL (group->uridecodebin, group->autoplug_factories_id);
     REMOVE_SIGNAL (group->uridecodebin, group->autoplug_select_id);

gst/playback/gsturidecodebin.c

@@ -1350,21 +1350,6 @@ gen_source_element (GstURIDecodeBin * decoder)
 
   GST_LOG_OBJECT (decoder, "found source type %s", G_OBJECT_TYPE_NAME (source));
 
-  decoder->is_stream = IS_STREAM_URI (decoder->uri);
-
-  query = gst_query_new_scheduling ();
-  if (gst_element_query (source, query)) {
-    gst_query_parse_scheduling (query, &flags, NULL, NULL, NULL);
-    if ((flags & GST_SCHEDULING_FLAG_BANDWIDTH_LIMITED))
-      decoder->is_stream = TRUE;
-  }
-  gst_query_unref (query);
-
-  GST_LOG_OBJECT (decoder, "source is stream: %d", decoder->is_stream);
-
-  decoder->need_queue = IS_QUEUE_URI (decoder->uri);
-  GST_LOG_OBJECT (decoder, "source needs queue: %d", decoder->need_queue);
-
   source_class = G_OBJECT_GET_CLASS (source);
 
   pspec = g_object_class_find_property (source_class, "connection-speed");
@@ -1411,6 +1396,25 @@ gen_source_element (GstURIDecodeBin * decoder)
         "setting subtitle-encoding=%s to source element", decoder->encoding);
     g_object_set (source, "subtitle-encoding", decoder->encoding, NULL);
   }
+
+  g_signal_emit (decoder, gst_uri_decode_bin_signals[SIGNAL_SOURCE_SETUP],
+      0, source);
+
+  decoder->is_stream = IS_STREAM_URI (decoder->uri);
+
+  query = gst_query_new_scheduling ();
+  if (gst_element_query (source, query)) {
+    gst_query_parse_scheduling (query, &flags, NULL, NULL, NULL);
+    if ((flags & GST_SCHEDULING_FLAG_BANDWIDTH_LIMITED))
+      decoder->is_stream = TRUE;
+  }
+  gst_query_unref (query);
+
+  GST_LOG_OBJECT (decoder, "source is stream: %d", decoder->is_stream);
+
+  decoder->need_queue = IS_QUEUE_URI (decoder->uri);
+  GST_LOG_OBJECT (decoder, "source needs queue: %d", decoder->need_queue);
+
   return source;
 
   /* ERRORS */
@@ -2262,9 +2266,6 @@ setup_source (GstURIDecodeBin * decoder)
   /* notify of the new source used */
   g_object_notify (G_OBJECT (decoder), "source");
 
-  g_signal_emit (decoder, gst_uri_decode_bin_signals[SIGNAL_SOURCE_SETUP],
-      0, decoder->source);
-
   if (is_live_source (decoder->source))
     decoder->is_stream = FALSE;