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/* 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <string.h>
#include <math.h>
#include <gst/gst.h>
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 *list;
const GValue *value;
gint i;
if (!gst_structure_get_clock_time (s, "endtime", &endtime))
g_warning ("Could not parse endtime");
/* we can get the number of channels as the length of any of the value
* lists */
list = gst_structure_get_value (s, "rms");
channels = gst_value_list_get_size (list);
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);
list = gst_structure_get_value (s, "rms");
value = gst_value_list_get_value (list, i);
rms_dB = g_value_get_double (value);
list = gst_structure_get_value (s, "peak");
value = gst_value_list_get_value (list, i);
peak_dB = g_value_get_double (value);
list = gst_structure_get_value (s, "decay");
value = gst_value_list_get_value (list, 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;
gint watch_id;
GMainLoop *loop;
gst_init (&argc, &argv);
caps = gst_caps_from_string ("audio/x-raw-int,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);
g_assert (gst_element_link (audiotestsrc, audioconvert));
g_assert (gst_element_link_filtered (audioconvert, level, caps));
g_assert (gst_element_link (level, fakesink));
/* make sure we'll get messages */
g_object_set (G_OBJECT (level), "message", 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);
return 0;
}
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