Add a simple example application for the spectrum element, include it in the docs, and fix some documentation ambigui...

Original commit message from CVS:
* docs/plugins/Makefile.am:
* gst/spectrum/gstspectrum.c:
* tests/examples/spectrum/.cvsignore:
* tests/examples/spectrum/Makefile.am:
* tests/examples/spectrum/spectrum-example.c:
Add a simple example application for the spectrum element, include it
in the docs, and fix some documentation ambiguities.
Fixes: #348085

3 files changed, 128 insertions, 1 deletions

diff --git a/tests/examples/spectrum/.gitignore b/tests/examples/spectrum/.gitignore
index d1d65d58..8e5a3cf9 100644
--- a/tests/examples/spectrum/.gitignore
+++ b/tests/examples/spectrum/.gitignore
@@ -1,2 +1,3 @@
 demo-audiotest
 demo-osssrc
+spectrum-example
diff --git a/tests/examples/spectrum/Makefile.am b/tests/examples/spectrum/Makefile.am
index 0fd2ef17..a0a71629 100644
--- a/tests/examples/spectrum/Makefile.am
+++ b/tests/examples/spectrum/Makefile.am
@@ -1,5 +1,5 @@
 if HAVE_GTK
-noinst_PROGRAMS = demo-osssrc demo-audiotest
+noinst_PROGRAMS = demo-osssrc demo-audiotest spectrum-example
 endif
 
 demo_osssrc_SOURCES = demo-osssrc.c
@@ -10,3 +10,7 @@ demo_audiotest_SOURCES = demo-audiotest.c
 demo_audiotest_CFLAGS  = $(GST_BASE_CFLAGS) $(GST_CFLAGS) $(GTK_CFLAGS)
 demo_audiotest_LDFLAGS = $(GST_BASE_LIBS) $(GST_LIBS) $(GTK_LIBS)
 
+spectrum_example_SOURCES = spectrum-example.c
+spectrum_example_CFLAGS  = $(GST_BASE_CFLAGS) $(GST_CFLAGS) $(GTK_CFLAGS)
+spectrum_example_LDFLAGS = $(GST_BASE_LIBS) $(GST_LIBS) $(GTK_LIBS)
+
diff --git a/tests/examples/spectrum/spectrum-example.c b/tests/examples/spectrum/spectrum-example.c
new file mode 100644
index 00000000..7c20e279
--- /dev/null
+++ b/tests/examples/spectrum/spectrum-example.c
@@ -0,0 +1,122 @@
+/* GStreamer
+ * Copyright (C) 2006 Stefan Kost <ensonic@users.sf.net>
+ * Copyright (C) 2008 Jan Schmidt <jan.schmidt@sun.com>
+ *
+ * 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 <gst/gst.h>
+
+static guint spect_bands = 20;
+
+#define AUDIOFREQ 32000
+
+/* receive spectral data from element message */
+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);
+    GstClockTime endtime;
+
+    if (strcmp (name, "spectrum") == 0) {
+      const GValue *magnitudes;
+      const GValue *phases;
+      const GValue *mag, *phase;
+      gdouble freq;
+      guint i;
+
+      if (!gst_structure_get_clock_time (s, "endtime", &endtime))
+        endtime = GST_CLOCK_TIME_NONE;
+
+      g_print ("New spectrum message, endtime %" GST_TIME_FORMAT "\n",
+          GST_TIME_ARGS (endtime));
+
+      magnitudes = gst_structure_get_value (s, "magnitude");
+      phases = gst_structure_get_value (s, "phase");
+
+      for (i = 0; i < spect_bands; ++i) {
+        freq = (gdouble) ((AUDIOFREQ / 2) * i + AUDIOFREQ / 4) / spect_bands;
+        mag = gst_value_list_get_value (magnitudes, i);
+        phase = gst_value_list_get_value (phases, i);
+
+        if (mag != NULL && phase != NULL) {
+          g_print ("band %d (freq %g): magnitude %f dB phase %f\n", i, freq,
+              g_value_get_float (mag), g_value_get_float (phase));
+        }
+      }
+      g_print ("\n");
+    }
+  }
+  return TRUE;
+}
+
+int
+main (int argc, char *argv[])
+{
+  GstElement *bin;
+  GstElement *src, *audioconvert, *spectrum, *sink;
+  GstBus *bus;
+  GstCaps *caps;
+  GMainLoop *loop;
+
+  gst_init (&argc, &argv);
+
+  bin = gst_pipeline_new ("bin");
+
+  src = gst_element_factory_make ("audiotestsrc", "src");
+  g_object_set (G_OBJECT (src), "wave", 0, "freq", 6000.0, NULL);
+  audioconvert = gst_element_factory_make ("audioconvert", NULL);
+  g_assert (audioconvert);
+
+  spectrum = gst_element_factory_make ("spectrum", "spectrum");
+  g_object_set (G_OBJECT (spectrum), "bands", spect_bands, "threshold", -80,
+      "message", TRUE, "message-phase", TRUE, NULL);
+
+  sink = gst_element_factory_make ("fakesink", "sink");
+  g_object_set (G_OBJECT (sink), "sync", TRUE, NULL);
+
+  gst_bin_add_many (GST_BIN (bin), src, audioconvert, spectrum, sink, NULL);
+
+  caps = gst_caps_new_simple ("audio/x-raw-int",
+      "rate", G_TYPE_INT, AUDIOFREQ, NULL);
+
+  if (!gst_element_link (src, audioconvert) ||
+      !gst_element_link_filtered (audioconvert, spectrum, caps) ||
+      !gst_element_link (spectrum, sink)) {
+    fprintf (stderr, "can't link elements\n");
+    exit (1);
+  }
+  gst_caps_unref (caps);
+
+  bus = gst_element_get_bus (bin);
+  gst_bus_add_watch (bus, message_handler, NULL);
+  gst_object_unref (bus);
+
+  gst_element_set_state (bin, 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);
+
+  gst_element_set_state (bin, GST_STATE_NULL);
+
+  gst_object_unref (bin);
+
+  return 0;
+}