1 files changed, 140 insertions, 0 deletions
diff --git a/tests/examples/level/level-example.c b/tests/examples/level/level-example.c
new file mode 100644
index 0000000..a953176
--- /dev/null
+++ b/tests/examples/level/level-example.c
@@ -0,0 +1,140 @@
+/* GStreamer
+ * Copyright (C) 2000,2001,2002,2003,2005
+ *           Thomas Vander Stichele <thomas at apestaart dot org>
+ *
+ * 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.
+ */
+
+#include <string.h>
+#include <math.h>
+
+#define GLIB_DISABLE_DEPRECATION_WARNINGS
+
+#include <gst/gst.h>
+
+static gboolean
+message_handler (GstBus * bus, GstMessage * message, gpointer data)
+{
+
+  if (message->type == GST_MESSAGE_ELEMENT) {
+    const GstStructure *s = gst_message_get_structure (message);
+    const gchar *name = gst_structure_get_name (s);
+
+    if (strcmp (name, "level") == 0) {
+      gint channels;
+      GstClockTime endtime;
+      gdouble rms_dB, peak_dB, decay_dB;
+      gdouble rms;
+      const GValue *array_val;
+      const GValue *value;
+      GValueArray *rms_arr, *peak_arr, *decay_arr;
+      gint i;
+
+      if (!gst_structure_get_clock_time (s, "endtime", &endtime))
+        g_warning ("Could not parse endtime");
+
+      /* the values are packed into GValueArrays with the value per channel */
+      array_val = gst_structure_get_value (s, "rms");
+      rms_arr = (GValueArray *) g_value_get_boxed (array_val);
+
+      array_val = gst_structure_get_value (s, "peak");
+      peak_arr = (GValueArray *) g_value_get_boxed (array_val);
+
+      array_val = gst_structure_get_value (s, "decay");
+      decay_arr = (GValueArray *) g_value_get_boxed (array_val);
+
+      /* we can get the number of channels as the length of any of the value
+       * arrays */
+      channels = rms_arr->n_values;
+      g_print ("endtime: %" GST_TIME_FORMAT ", channels: %d\n",
+          GST_TIME_ARGS (endtime), channels);
+      for (i = 0; i < channels; ++i) {
+
+        g_print ("channel %d\n", i);
+        value = g_value_array_get_nth (rms_arr, i);
+        rms_dB = g_value_get_double (value);
+
+        value = g_value_array_get_nth (peak_arr, i);
+        peak_dB = g_value_get_double (value);
+
+        value = g_value_array_get_nth (decay_arr, i);
+        decay_dB = g_value_get_double (value);
+        g_print ("    RMS: %f dB, peak: %f dB, decay: %f dB\n",
+            rms_dB, peak_dB, decay_dB);
+
+        /* converting from dB to normal gives us a value between 0.0 and 1.0 */
+        rms = pow (10, rms_dB / 20);
+        g_print ("    normalized rms value: %f\n", rms);
+      }
+    }
+  }
+  /* we handled the message we want, and ignored the ones we didn't want.
+   * so the core can unref the message for us */
+  return TRUE;
+}
+
+int
+main (int argc, char *argv[])
+{
+  GstElement *audiotestsrc, *audioconvert, *level, *fakesink;
+  GstElement *pipeline;
+  GstCaps *caps;
+  GstBus *bus;
+  guint watch_id;
+  GMainLoop *loop;
+
+  gst_init (&argc, &argv);
+
+  caps = gst_caps_from_string ("audio/x-raw,channels=2");
+
+  pipeline = gst_pipeline_new (NULL);
+  g_assert (pipeline);
+  audiotestsrc = gst_element_factory_make ("audiotestsrc", NULL);
+  g_assert (audiotestsrc);
+  audioconvert = gst_element_factory_make ("audioconvert", NULL);
+  g_assert (audioconvert);
+  level = gst_element_factory_make ("level", NULL);
+  g_assert (level);
+  fakesink = gst_element_factory_make ("fakesink", NULL);
+  g_assert (fakesink);
+
+  gst_bin_add_many (GST_BIN (pipeline), audiotestsrc, audioconvert, level,
+      fakesink, NULL);
+  if (!gst_element_link (audiotestsrc, audioconvert))
+    g_error ("Failed to link audiotestsrc and audioconvert");
+  if (!gst_element_link_filtered (audioconvert, level, caps))
+    g_error ("Failed to link audioconvert and level");
+  if (!gst_element_link (level, fakesink))
+    g_error ("Failed to link level and fakesink");
+
+  /* make sure we'll get messages */
+  g_object_set (G_OBJECT (level), "post-messages", TRUE, NULL);
+  /* run synced and not as fast as we can */
+  g_object_set (G_OBJECT (fakesink), "sync", TRUE, NULL);
+
+  bus = gst_element_get_bus (pipeline);
+  watch_id = gst_bus_add_watch (bus, message_handler, NULL);
+
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+  /* we need to run a GLib main loop to get the messages */
+  loop = g_main_loop_new (NULL, FALSE);
+  g_main_loop_run (loop);
+
+  g_source_remove (watch_id);
+  g_main_loop_unref (loop);
+  return 0;
+}