added second example with plotting fixed some aesthetics

Original commit message from CVS:
added second example with plotting
fixed some aesthetics

gst/level/Makefile.am

@@ -9,10 +9,13 @@ libgstlevel_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
 noinst_HEADERS = gstlevel.h filter.func
 
 if HAVE_GTK
-noinst_PROGRAMS = demo
+noinst_PROGRAMS = demo plot
 demo_SOURCES = demo.c
 demo_CFLAGS = $(GTK_CFLAGS) $(GST_CFLAGS)
 demo_LDFLAGS = $(GTK_LIBS) $(GST_LIBS)
+plot_SOURCES = plot.c
+plot_CFLAGS = $(GTK_CFLAGS) $(GST_CFLAGS)
+plot_LDFLAGS = $(GTK_LIBS) $(GST_LIBS)
 endif
 
 EXTRA_libgstlevel_la_SOURCES = gstlevel-marshal.list

gst/level/README

@@ -1,6 +1,7 @@
 level plugin by thomas <thomas@apestaart.org>
 
 this plugin signals:
+  - running time since last EOS/start
   - channel
   - RMS level
   - peak level
@@ -18,4 +19,21 @@ The element only takes unsigned data in; it could be extended to signed as
 well, if separate fast chain functions are made that displaces the incoming
 data to its midpoint (ie, 0,65535 should be mapped to -32768, 32767)
 
+There are two demo apps, apps and plot.  apps will create some GTK sliders
+to display the volume.  plot will output data readable by gnuplot.
+
+Here is a sample plot script to plot output of the plot command that was
+stored to plot.dat
+
+set xlabel "Seconds"
+set ylabel "dB"
+set yrange [-60:0]
+plot 'plot.dat' using 1:2 title 'L RMS' with lines, \
+     'plot.dat' using 1:3 title 'L peak' with lines, \
+     'plot.dat' using 1:4 title 'L decay' with lines
+
+plot 'plot.dat' using 1:5 title 'R RMS' with lines, \
+     'plot.dat' using 1:6 title 'R peak' with lines, \
+     'plot.dat' using 1:7 title 'R decay' with lines
+
 

gst/level/demo.c

@@ -28,7 +28,7 @@
 GtkWidget *scale[2][3];
 
 static void
-level_callback (GstElement *element, gint channel,
+level_callback (GstElement *element, gdouble time, gint channel,
                 gdouble rms, gdouble peak, gdouble decay)
 {
   gtk_range_set_value (GTK_RANGE (scale[channel][0]), rms);
@@ -41,7 +41,10 @@ idler (gpointer data)
 {
   GstElement *pipeline = GST_ELEMENT (data);
   g_print ("+");
-  return gst_bin_iterate (GST_BIN (pipeline));
+  if (gst_bin_iterate (GST_BIN (pipeline)))
+    return TRUE;
+  gtk_main_quit ();
+  return FALSE;
 }
 
 static void

gst/level/gstlevel-marshal.list

@@ -1 +1 @@
-VOID:INT,DOUBLE,DOUBLE,DOUBLE
+VOID:DOUBLE,INT,DOUBLE,DOUBLE,DOUBLE

gst/level/gstlevel.c

@@ -214,7 +214,7 @@ gst_level_chain (GstPad *pad, GstBuffer *buf)
   for (i = 0; i < filter->channels; ++i)
     filter->CS[i] = filter->peak[i] = filter->MS[i] = filter->RMS_dB[i] = 0.0;
   
-  in_data = (gint16 *) GST_BUFFER_DATA(buf);
+  in_data = (gint16 *) GST_BUFFER_DATA (buf);
   
   num_samples = GST_BUFFER_SIZE (buf) / (filter->width / 8);
   if (num_samples % filter->channels != 0)
@@ -288,14 +288,18 @@ gst_level_chain (GstPad *pad, GstBuffer *buf)
   {
     if (filter->signal)
     {
-      gdouble RMS, peak;
+      gdouble RMS, peak, endtime;
       for (i = 0; i < filter->channels; ++i)
       {
         RMS = sqrt (filter->CS[i] / (filter->num_samples / filter->channels));
         peak = filter->last_peak[i];
+        num_samples = GST_BUFFER_SIZE (buf) / (filter->width / 8);
+        endtime = (double) GST_BUFFER_TIMESTAMP (buf) / GST_SECOND
+                + (double) num_samples / (double) filter->rate;
 
         g_signal_emit (G_OBJECT (filter), gst_filter_signals[SIGNAL_LEVEL], 0,
-                       i, 20 * log10 (RMS), 20 * log10 (filter->last_peak[i]),
+                       endtime, i,
+                       20 * log10 (RMS), 20 * log10 (filter->last_peak[i]),
                        20 * log10 (filter->decay_peak[i]));
         /* we emitted, so reset cumulative and normal peak */
         filter->CS[i] = 0.0;
@@ -397,9 +401,10 @@ gst_level_class_init (GstLevelClass *klass)
   gst_filter_signals[SIGNAL_LEVEL] = 
     g_signal_new ("level", G_TYPE_FROM_CLASS(klass), G_SIGNAL_RUN_LAST,
                   G_STRUCT_OFFSET (GstLevelClass, level), NULL, NULL,
-                  gstlevel_cclosure_marshal_VOID__INT_DOUBLE_DOUBLE_DOUBLE,
-                  G_TYPE_NONE, 4,
-                  G_TYPE_INT, G_TYPE_DOUBLE, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
+                  gstlevel_cclosure_marshal_VOID__DOUBLE_INT_DOUBLE_DOUBLE_DOUBLE,
+                  G_TYPE_NONE, 5,
+                  G_TYPE_DOUBLE, G_TYPE_INT,
+                  G_TYPE_DOUBLE, G_TYPE_DOUBLE, G_TYPE_DOUBLE);
 }
 
 static void

gst/level/gstlevel.h

@@ -77,7 +77,7 @@ struct _GstLevel {
 
 struct _GstLevelClass {
   GstElementClass parent_class;
-  void (*level) (GstElement *element, gint channel,
+  void (*level) (GstElement *element, gdouble time, gint channel,
                  gdouble RMS_dB, gdouble peak_dB, gdouble decay_peak_dB);
 };
 

gst/level/plot.c

@@ -0,0 +1,120 @@
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * plot.c: output data points to be graphed with gnuplot
+ * Copyright (C) 2003
+ *           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 <gst/gst.h>
+#include <gtk/gtk.h>
+
+gboolean got_channel[2] = { FALSE, FALSE}; /* to see if we got the signal for this one yet */
+gint channels = 0 ;      /* guess at how many channels there are */
+gdouble last_time = 0.0; /* time of last signal */
+gdouble values[2][3];    /* array of levels from which to print */
+
+static void
+level_callback (GstElement *element, gdouble time, gint channel,
+                gdouble rms, gdouble peak, gdouble decay)
+{
+  int i = 0, j = 0;
+  gboolean got_all = FALSE;
+
+  if (channel  + 1> channels) channels = channel + 1;
+
+  /* reset got_channel if this is a new time point */
+  if (time > last_time)
+  {
+    for (i = 0; i < channels; ++i)  got_channel[i] = FALSE;
+    last_time = time;
+  }
+
+  /* store values */
+  got_channel[channel] = TRUE;
+  values[channel][0] = rms;
+  values[channel][1] = peak;
+  values[channel][2] = decay;
+
+  /* check if we have all channels, and output if we do */
+  /* FIXME: this fails on the first, no ? */
+  got_all = TRUE;
+  for (i = 0; i < channels; ++i)
+    if (!got_channel[i]) got_all = FALSE;
+  if (got_all)
+  {
+    g_print ("%f ", time);
+    for (i = 0; i < channels; ++i)
+      for (j = 0; j < 3; ++j)
+        g_print ("%f ", values[i][j]);
+    g_print ("\n");
+  }
+}
+
+static gboolean
+idler (gpointer data)
+{
+  GstElement *pipeline = GST_ELEMENT (data);
+  if (gst_bin_iterate (GST_BIN (pipeline)))
+    return TRUE;
+
+  gtk_main_quit ();
+  return FALSE;
+}
+
+int main
+(int argc, char *argv[])
+{
+
+  GstElement *pipeline = NULL;
+  GError *error = NULL;
+  GstElement *level;
+
+  gst_init (&argc, &argv);
+  gtk_init (&argc, &argv);
+
+  pipeline = gst_parse_launchv ((const gchar **) &argv[1], &error);
+  if (error)
+  {
+    g_print ("pipeline could not be constructed: %s\n", error->message);
+    g_print ("Please give a complete pipeline  with a 'level' element.\n");
+    g_print ("Example: sinesrc ! level ! osssink\n");
+    g_error_free (error);
+    return 1;
+  }
+
+  level = gst_bin_get_by_name (GST_BIN (pipeline), "level0");
+  if (level == NULL)
+  {
+    g_print ("Please give a pipeline with a 'level' element in it\n");
+    return 1;
+  }
+
+  g_object_set (level, "signal", TRUE, NULL);
+  g_signal_connect (level, "level", G_CALLBACK (level_callback), NULL);
+
+  
+  /* go to main loop */
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+  g_idle_add (idler, pipeline);
+
+  gtk_main ();
+
+  return 0;
+}
+