blob: a953176d840206e86cc6a0ccb0489558baacb403 [file] [log] [blame]
/* 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
* 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>
#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;
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;