Small example that shows caps nego recovery.

Original commit message from CVS:
Small example that shows caps nego recovery.

tests/negotiation/.gitignore

@@ -0,0 +1 @@
+capsnego1

tests/negotiation/Makefile.am

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+
+noinst_PROGRAMS = capsnego1
+
+LDADD = $(GST_LIBS)
+AM_CFLAGS = $(GST_CFLAGS) 

tests/negotiation/capsnego1.c

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+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * 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.
+ */
+
+#include <gst/gst.h>
+
+static void
+caps_nego_failed (GstPad *pad, GstCaps *caps)
+{
+  gboolean res;
+  GstPad *peer;
+  GstCaps *allowed;
+  GValue v_caps = { 0, }; 
+  GValue v_allowed = { 0, };
+  GstCaps *toset;
+  
+  peer = gst_pad_get_peer (pad);
+  g_value_init (&v_caps, GST_TYPE_CAPS);
+  g_value_set_boxed  (&v_caps, caps);
+  allowed = gst_pad_get_allowed_caps (pad);
+  g_value_init (&v_allowed, GST_TYPE_CAPS);
+  g_value_set_boxed  (&v_allowed, allowed);
+
+  g_print ("caps nego failed on pad %s:%s\n"
+	   " caps:    %p (%s)\n"
+	   " allowed: %p (%s)\n", 
+		  gst_element_get_name (gst_pad_get_parent (pad)),
+		  gst_pad_get_name (pad),
+		  caps,
+		  g_strdup_value_contents (&v_caps),
+		  allowed,
+		  g_strdup_value_contents (&v_allowed));
+
+  if (GST_CAPS_IS_FIXED (caps)) 
+    /* if the elements suggested fixed caps, we just relink that way */
+    toset = caps;
+  else
+    /* else we use our hardcoded caps as an exazmple */
+    toset = GST_CAPS_NEW (
+	     "testcaps",
+	     "test/test",
+	       "prop", GST_PROPS_INT (2)
+	    );
+
+  res = gst_pad_relink_filtered (pad, peer, toset);
+  if (!res) {
+    g_warning ("could not relink identity and sink\n");
+  }
+}
+
+gint 
+main (gint argc, gchar *argv[])
+{
+  GstElement *pipeline;
+  GstElement *src, *identity, *sink;
+  gboolean res;
+
+  gst_init (&argc, &argv);
+
+  pipeline = gst_pipeline_new ("pipeline");
+
+  src = gst_element_factory_make ("fakesrc", "src");
+  g_object_set (G_OBJECT (src), "num_buffers", 4, NULL);
+  identity = gst_element_factory_make ("identity", "identity");
+  g_object_set (G_OBJECT (identity), "delay_capsnego", TRUE, NULL);
+  
+  sink = gst_element_factory_make ("fakesink", "sink");
+
+  gst_bin_add_many (GST_BIN (pipeline), src, identity, sink, NULL);
+  
+  res = gst_element_link_pads_filtered (src, "src",
+		                  identity, "sink",
+				  GST_CAPS_NEW (
+				    "testcaps",
+				    "test/test",
+				      "prop", GST_PROPS_INT (1)
+				  ));
+  if (!res) {
+    g_print ("could not link src and identity\n");
+    return -1;
+  }
+					  
+  res = gst_element_link_pads_filtered (identity, "src",
+		                  sink, "sink",
+				  GST_CAPS_NEW (
+				    "testcaps",
+				    "test/test",
+				      "prop", GST_PROPS_INT_RANGE (2, 3)
+				  ));
+  if (!res) {
+    g_print ("could not link identity and sink\n");
+    return -1;
+  }
+
+  g_signal_connect (gst_element_get_pad (identity, "src"), 
+		    "caps_nego_failed", G_CALLBACK (caps_nego_failed), NULL);
+
+  g_signal_connect (pipeline, "deep_notify", G_CALLBACK (gst_element_default_deep_notify), NULL);
+  g_signal_connect (pipeline, "error", G_CALLBACK (gst_element_default_error), NULL);
+
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+  while (gst_bin_iterate (GST_BIN (pipeline)));
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  
+  return 0;
+}