+2005-09-14 Thomas Vander Stichele <thomas at apestaart dot org>
+
+ * common/c-to-xml.py:
+ * common/gtk-doc-plugins.mak:
+ a simple py script to generate valid xml from a C example
+ probably also need to strip an MIT license when we decide
+ * docs/plugins/Makefile.am:
+ * gst/level/Makefile.am:
+ * gst/level/gstlevel.c: (gst_level_init):
+ * gst/level/level-example.c: (message_handler), (main):
+ add an example to level that will show up in the docs
+ * gst/rtp/TODO:
+ add a note for the future
+
2005-09-14 Michael Smith <msmith@fluendo.com>
* gst/wavenc/gstwavenc.c: (gst_wavenc_class_init):
* Boston, MA 02111-1307, USA.
*/
+/**
+ * SECTION:element-level
+ *
+ * <refsect2>
+ * <para>
+ * Level analyses incoming audio buffers and generates an application
+ * message per given interval of time.
+ * The message's structure contains four fields:
+ * <itemizedlist>
+ * <listitem>
+ * <para>
+ * <link linkend="gdouble">gdouble</link>
+ * <classname>"endtime"</classname>:
+ * the end time of the buffer that
+ * triggered the message</para>
+ * </listitem>
+ * <listitem>
+ * <para>
+ * <link linkend="gdouble">gdouble</link>
+ * <classname>"endtime"</classname>:
+ * the end time of the buffer that
+ * triggered the message</para>
+ * </listitem>
+ * </itemizedlist>
+ * </para>
+ * <title>Example application</title>
+ * <para>
+ * <include xmlns="http://www.w3.org/2003/XInclude" href="element-level-example.xml" />
+ * </para>
+ * </refsect2>
+ */
+
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
filter->interval = 0.1;
filter->decay_peak_ttl = 0.4;
filter->decay_peak_falloff = 10.0; /* dB falloff (/sec) */
+
+ filter->message = TRUE;
}
static void
* samples for multiple channels are interleaved
* input sample data enters in *in_data as 8 or 16 bit data
* this filter only accepts signed audio data, so mid level is always 0
+ *
+ * for 16 bit, this code considers the non-existant 32768 value to be
+ * full-scale; so 32767 will not map to 1.0
*/
#define DEFINE_LEVEL_CALCULATOR(TYPE) \
double squaresum = 0.0; /* square sum of the integer samples */ \
register double square = 0.0; /* Square */ \
register double PSS = 0.0; /* Peak Square Sample */ \
- gdouble normalizer; /* divisor to get a [-1, - 1] range */ \
+ gdouble normalizer; /* divisor to get a [-1.0, 1.0] range */ \
\
*CS = 0.0; /* Cumulative Square for this block */ \
\
--- /dev/null
+#include <string.h>
+#include <math.h>
+
+#include <gst/gst.h>
+
+gboolean
+message_handler (GstBus * bus, GstMessage * message, gpointer data)
+{
+
+ if (message->type == GST_MESSAGE_APPLICATION) {
+ const GstStructure *s = gst_message_get_structure (message);
+ const gchar *name = gst_structure_get_name (s);
+
+ if (strcmp (name, "level") == 0) {
+ gint channels;
+ gdouble endtime, rms_dB, peak_dB, decay_dB;
+ gdouble rms;
+ const GValue *list;
+ const GValue *value;
+
+ if (!gst_structure_get_double (s, "endtime", &endtime))
+ g_warning ("Could not parse endtime");
+ list = gst_structure_get_value (s, "rms");
+ /* we can get the number of channels as the length of any of the value
+ * lists */
+ channels = gst_value_list_get_size (list);
+
+ /* we will only get values for the first channel, since we know sinesrc
+ * is mono */
+ value = gst_value_list_get_value (list, 0);
+ rms_dB = g_value_get_double (value);
+ list = gst_structure_get_value (s, "peak");
+ value = gst_value_list_get_value (list, 0);
+ peak_dB = g_value_get_double (value);
+ list = gst_structure_get_value (s, "decay");
+ value = gst_value_list_get_value (list, 0);
+ decay_dB = g_value_get_double (value);
+ g_print ("endtime: %f, channels: %d\n", endtime, channels);
+ 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 *sinesrc, *level, *fakesink;
+ GstElement *pipeline;
+ GstBus *bus;
+ gint watch_id;
+ GMainLoop *loop;
+
+ gst_init (&argc, &argv);
+
+ pipeline = gst_pipeline_new (NULL);
+ g_assert (pipeline);
+ sinesrc = gst_element_factory_make ("sinesrc", NULL);
+ g_assert (sinesrc);
+ 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), sinesrc, level, fakesink, NULL);
+ gst_element_link (sinesrc, level);
+ 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;
+}
projects / platform / upstream / gst-plugins-good.git / commitdiff