gst/equalizer/: Better algorith for the center frequencies. Subtract band filters from input for negative gains. Rewo...

Original commit message from CVS:
* gst/equalizer/gstiirequalizer.c:
(gst_iir_equalizer_band_set_property),
(gst_iir_equalizer_child_proxy_get_child_by_index),
(gst_iir_equalizer_child_proxy_get_children_count),
(gst_iir_equalizer_child_proxy_interface_init),
(gst_iir_equalizer_class_init), (arg_to_scale), (setup_filter),
(gst_iir_equalizer_compute_frequencies):
* gst/equalizer/gstiirequalizer10bands.c:
(gst_iir_equalizer_10bands_class_init):
* gst/equalizer/gstiirequalizer3bands.c:
(gst_iir_equalizer_3bands_class_init):
* gst/equalizer/gstiirequalizernbands.c:
Better algorith for the center frequencies. Subtract band filters from
input for negative gains. Rework the gain mapping.

5 files changed, 83 insertions, 78 deletions

diff --git a/ChangeLog b/ChangeLog
index 1cfaf729..32cf411d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,22 @@
 2007-07-20  Stefan Kost  <ensonic@users.sf.net>
 
+	* gst/equalizer/gstiirequalizer.c:
+	(gst_iir_equalizer_band_set_property),
+	(gst_iir_equalizer_child_proxy_get_child_by_index),
+	(gst_iir_equalizer_child_proxy_get_children_count),
+	(gst_iir_equalizer_child_proxy_interface_init),
+	(gst_iir_equalizer_class_init), (arg_to_scale), (setup_filter),
+	(gst_iir_equalizer_compute_frequencies):
+	* gst/equalizer/gstiirequalizer10bands.c:
+	(gst_iir_equalizer_10bands_class_init):
+	* gst/equalizer/gstiirequalizer3bands.c:
+	(gst_iir_equalizer_3bands_class_init):
+	* gst/equalizer/gstiirequalizernbands.c:
+	  Better algorith for the center frequencies. Subtract band filters from
+	  input for negative gains. Rework the gain mapping.
+
+2007-07-20  Stefan Kost  <ensonic@users.sf.net>
+
 	* ext/dirac/Makefile.am:
 	  Also include stdlib here.
 
diff --git a/gst/equalizer/gstiirequalizer.c b/gst/equalizer/gstiirequalizer.c
index 1bb240e9..f73eff8b 100644
--- a/gst/equalizer/gstiirequalizer.c
+++ b/gst/equalizer/gstiirequalizer.c
@@ -141,7 +141,7 @@ gst_iir_equalizer_band_set_property (GObject * object, guint prop_id,
       gdouble gain;
 
       gain = g_value_get_double (value);
-      GST_INFO_OBJECT (band, "gain = %lf -> %lf", band->gain, gain);
+      GST_DEBUG_OBJECT (band, "gain = %lf -> %lf", band->gain, gain);
       if (gain != band->gain) {
         GstIirEqualizer *equ =
             GST_IIR_EQUALIZER (gst_object_get_parent (GST_OBJECT (band)));
@@ -151,7 +151,7 @@ gst_iir_equalizer_band_set_property (GObject * object, guint prop_id,
           setup_filter (equ, band);
         }
         gst_object_unref (equ);
-        GST_INFO_OBJECT (band, "changed gain = %lf ", band->gain);
+        GST_DEBUG_OBJECT (band, "changed gain = %lf ", band->gain);
       }
       break;
     }
@@ -233,8 +233,7 @@ gst_iir_equalizer_child_proxy_get_child_by_index (GstChildProxy * child_proxy,
 
   g_return_val_if_fail (index < equ->freq_band_count, NULL);
 
-  GST_INFO ("return child[%d] '%s'", index,
-      GST_OBJECT_NAME (equ->bands[index]));
+  GST_LOG ("return child[%d] '%s'", index, GST_OBJECT_NAME (equ->bands[index]));
   return (gst_object_ref (equ->bands[index]));
 }
 
@@ -243,7 +242,7 @@ gst_iir_equalizer_child_proxy_get_children_count (GstChildProxy * child_proxy)
 {
   GstIirEqualizer *equ = GST_IIR_EQUALIZER (child_proxy);
 
-  GST_INFO ("we have %d children", equ->freq_band_count);
+  GST_LOG ("we have %d children", equ->freq_band_count);
   return (equ->freq_band_count);
 }
 
@@ -253,7 +252,7 @@ gst_iir_equalizer_child_proxy_interface_init (gpointer g_iface,
 {
   GstChildProxyInterface *iface = g_iface;
 
-  GST_INFO ("initializing iface");
+  GST_DEBUG ("initializing iface");
 
   iface->get_child_by_index = gst_iir_equalizer_child_proxy_get_child_by_index;
   iface->get_children_count = gst_iir_equalizer_child_proxy_get_children_count;
@@ -288,7 +287,7 @@ gst_iir_equalizer_class_init (GstIirEqualizerClass * klass)
   g_object_class_install_property (gobject_class, ARG_BAND_WIDTH,
       g_param_spec_double ("band-width", "band-width",
           "band width calculated as distance between bands * this value", 0.1,
-          5.0, 1.0, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
+          10.0, 1.0, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
 
   audio_filter_class->setup = gst_iir_equalizer_setup;
   btrans_class->transform_ip = gst_iir_equalizer_transform_ip;
@@ -314,19 +313,20 @@ gst_iir_equalizer_finalize (GObject * object)
 /*
  * converts gain values to scale factors.
  *
- * arguments are in the range [-1 ... 1] with 0 meaning "no action"
- * results are in the range [-0.2 ... 1] with 0 meaning "no action"
- * via the function
- *   f(x) = 0.25 * 5 ^ x - 0.25
+ * we map -1 ... 1 to a db range.
+ * A suitable range would be -12db ... 0 ... + 6db which expressed as
+ * a factor is about          0.06 ... 1 ... 4.0
+ *
+ * We need to subtract one so that gain is centered around zero
  *
  * visualize via gnuplot:
  *   set xrange [-1:1]
- *   plot 0.25 * exp (log (5) * x) - 0.25
+ *   plot 10.0 ** (12*x/10.0)
  */
 static gdouble
 arg_to_scale (gdouble arg)
 {
-  return 0.25 * exp (log (5) * arg) - 0.25;
+  return (pow (10.0, (6.0 * fabs (arg)) / 10.0) - 1.0);
 }
 
 static void
@@ -334,6 +334,10 @@ setup_filter (GstIirEqualizer * equ, GstIirEqualizerBand * band)
 {
   g_return_if_fail (GST_AUDIO_FILTER (equ)->format.rate);
 
+  /* FIXME: we need better filters
+   * - the band-width control is not good
+   * - we need shelf-filter for 1st and last band
+   */
   {
     gdouble gain = arg_to_scale (band->gain);
     gdouble frequency = band->freq / GST_AUDIO_FILTER (equ)->format.rate;
@@ -348,7 +352,9 @@ setup_filter (GstIirEqualizer * equ, GstIirEqualizerBand * band)
     band->beta *= 2.0;
     band->alpha *= 2.0 * gain;
     band->gamma *= 2.0;
-    GST_INFO ("gain = %g, frequency = %g, alpha = %g, beta = %g, gamma=%g",
+
+    GST_INFO
+        ("gain = %7.5g, frequency = %7.5g, alpha = %7.5g, beta = %7.5g, gamma=%7.5g",
         gain, frequency, band->alpha, band->beta, band->gamma);
   }
 }
@@ -357,7 +363,7 @@ void
 gst_iir_equalizer_compute_frequencies (GstIirEqualizer * equ, guint new_count)
 {
   guint old_count, i;
-  gdouble step = pow (HIGHEST_FREQ / LOWEST_FREQ, 1.0 / (new_count - 1));
+  gdouble freq0, freq1, step;
   gchar name[20];
 
   old_count = equ->freq_band_count;
@@ -396,36 +402,23 @@ gst_iir_equalizer_compute_frequencies (GstIirEqualizer * equ, guint new_count)
 
   /* set center frequencies and name band objects
    * FIXME: arg! we can't change the name of parented objects :(
-   *   application should read band->freq
-   * FIXME: the code that calculates the center-frequencies for the bands should
-   *   take the number of bands into account, when chooding the lowest frequency
+   *   application should read band->freq to get the name
    */
-  equ->bands[0]->freq = LOWEST_FREQ;
-  GST_DEBUG ("band[ 0] = '%lf'", equ->bands[0]->freq);
-  /*
-     if(equ->bands[0]->freq<10000.0) {
-     sprintf (name,"%dHz",(gint)equ->bands[0]->freq);
-     }
-     else {
-     sprintf (name,"%dkHz",(gint)(equ->bands[0]->freq/1000.0));
-     }
-     gst_object_set_name( GST_OBJECT (equ->bands[0]), name);
-     GST_DEBUG ("band[ 0] = '%s'",name);
-   */
-
-  for (i = 1; i < new_count; i++) {
-    equ->bands[i]->freq = equ->bands[i - 1]->freq * step;
+  step = pow (HIGHEST_FREQ / LOWEST_FREQ, 1.0 / new_count);
+  freq0 = LOWEST_FREQ;
+  for (i = 0; i < new_count; i++) {
+    freq1 = freq0 * step;
+    equ->bands[i]->freq = freq0 + ((freq1 - freq0) / 2.0);
     GST_DEBUG ("band[%2d] = '%lf'", i, equ->bands[i]->freq);
     /*
-       if(equ->bands[i]->freq<10000.0) {
+       if(equ->bands[i]->freq<10000.0)
        sprintf (name,"%dHz",(gint)equ->bands[i]->freq);
-       }
-       else {
+       else
        sprintf (name,"%dkHz",(gint)(equ->bands[i]->freq/1000.0));
-       }
        gst_object_set_name( GST_OBJECT (equ->bands[i]), name);
        GST_DEBUG ("band[%2d] = '%s'",i,name);
      */
+    freq0 = freq1;
   }
 
   if (GST_AUDIO_FILTER (equ)->format.rate) {
@@ -506,14 +499,15 @@ one_step_ ## TYPE (GstIirEqualizerBand *filter,                         \
   history->x2 = history->x1;                                            \
   history->x1 = input;                                                  \
                                                                         \
-  return output;                                                        \
+  /* for negative gains we subtract */                                  \
+  return (filter->gain>0.0) ? output : -output;                         \
 }                                                                       \
                                                                         \
 static const guint                                                      \
 history_size_ ## TYPE = sizeof (SecondOrderHistory ## TYPE);            \
                                                                         \
 static void                                                             \
-gst_iir_equ_process_ ## TYPE (GstIirEqualizer *equ, guint8 *data, \
+gst_iir_equ_process_ ## TYPE (GstIirEqualizer *equ, guint8 *data,       \
 guint size, guint channels)                                             \
 {                                                                       \
   guint frames = size / channels / sizeof (TYPE);                       \
@@ -525,14 +519,13 @@ guint size, guint channels)                                             \
     for (c = 0; c < channels; c++) {                                    \
       SecondOrderHistory ## TYPE *history = equ->history;               \
       val = *((TYPE *) data);                                           \
-      cur = 0;                                                          \
+      cur = 0.25 * val; /* FIXME: should be without factor*/            \
       for (f = 0; f < equ->freq_band_count; f++) {                      \
         GstIirEqualizerBand *filter = equ->bands[f];                    \
                                                                         \
         cur += one_step_ ## TYPE (filter, history, val);                \
         history++;                                                      \
       }                                                                 \
-      cur += val * 0.25;                                                \
       cur = CLAMP (cur, MIN_VAL, MAX_VAL);                              \
       *((TYPE *) data) = (TYPE) cur;                                    \
       data += sizeof (TYPE);                                            \
diff --git a/gst/equalizer/gstiirequalizer10bands.c b/gst/equalizer/gstiirequalizer10bands.c
index fb599d7e..785a3452 100644
--- a/gst/equalizer/gstiirequalizer10bands.c
+++ b/gst/equalizer/gstiirequalizer10bands.c
@@ -27,18 +27,13 @@
  * </para>
  * <para>
  * <programlisting>
- * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audioconvert ! equalizer-10bands band2=-1.0 ! alsasink
+ * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audioconvert ! equalizer-10bands band2=0.5 ! alsasink
  * </programlisting>
- * This lowers the volume of the 3rd band which is at 93 Hz by FIXME db.
+ * This raises the volume of the 3rd band which is at 119 Hz by 3 db.
  * </para>
  * </refsect2>
  */
 
-/*
- *
- * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audioconvert ! equalizer-10bands band1=-1.0 ! alsasink
- */
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -96,44 +91,44 @@ gst_iir_equalizer_10bands_class_init (GstIirEqualizer10BandsClass * klass)
   gobject_class->get_property = gst_iir_equalizer_10bands_get_property;
 
   g_object_class_install_property (gobject_class, ARG_BAND0,
-      g_param_spec_double ("band0", "20 Hz",
-          "gain for the frequency band 20 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band0", "29 Hz",
+          "gain for the frequency band 29 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND1,
-      g_param_spec_double ("band1", "43 Hz",
-          "gain for the frequency band 43 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band1", "59 Hz",
+          "gain for the frequency band 59 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND2,
-      g_param_spec_double ("band2", "93 Hz",
-          "gain for the frequency band 93 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band2", "119 Hz",
+          "gain for the frequency band 119 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND3,
-      g_param_spec_double ("band3", "200 Hz",
-          "gain for the frequency band 200 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band3", "227 Hz",
+          "gain for the frequency band 227 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND4,
-      g_param_spec_double ("band4", "430 Hz",
-          "gain for the frequency band 430 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band4", "474 Hz",
+          "gain for the frequency band 474 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND5,
-      g_param_spec_double ("band5", "928 Hz",
-          "gain for the frequency band 928 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band5", "947 Hz",
+          "gain for the frequency band 947 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND6,
-      g_param_spec_double ("band6", "2000 Hz",
-          "gain for the frequency band 2000 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band6", "1889 Hz",
+          "gain for the frequency band 1889 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND7,
-      g_param_spec_double ("band7", "4308 Hz",
-          "gain for the frequency band 4308 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band7", "3770 Hz",
+          "gain for the frequency band 3770 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND8,
-      g_param_spec_double ("band8", "9283 Hz",
-          "gain for the frequency band 9283 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band8", "7523 Hz",
+          "gain for the frequency band 7523 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND9,
-      g_param_spec_double ("band9", "20 kHz",
-          "gain for the frequency band 20 kHz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band9", "15011 Hz",
+          "gain for the frequency band 15011 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
 }
 
diff --git a/gst/equalizer/gstiirequalizer3bands.c b/gst/equalizer/gstiirequalizer3bands.c
index 17e7b553..08a1dfac 100644
--- a/gst/equalizer/gstiirequalizer3bands.c
+++ b/gst/equalizer/gstiirequalizer3bands.c
@@ -27,9 +27,9 @@
  * </para>
  * <para>
  * <programlisting>
- * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audioconvert ! equalizer-3bands band1=-1.0 ! alsasink
+ * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audioconvert ! equalizer-3bands band1=1.0 ! alsasink
  * </programlisting>
- * This lowers the volume of the 2nd band which is at 632 Hz by FIXME db.
+ * This raises the volume of the 2nd band which is at 1110 Hz by 6 db.
  * </para>
  * </refsect2>
  */
@@ -84,16 +84,16 @@ gst_iir_equalizer_3bands_class_init (GstIirEqualizer3BandsClass * klass)
   gobject_class->get_property = gst_iir_equalizer_3bands_get_property;
 
   g_object_class_install_property (gobject_class, ARG_BAND0,
-      g_param_spec_double ("band0", "20 Hz",
-          "gain for the frequency band 20 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band0", "110 Hz",
+          "gain for the frequency band 110 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND1,
-      g_param_spec_double ("band1", "632 Hz",
-          "gain for the frequency band 632 Hz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band1", "1110 Hz",
+          "gain for the frequency band 1110 Hz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
   g_object_class_install_property (gobject_class, ARG_BAND2,
-      g_param_spec_double ("band2", "20 kHz",
-          "gain for the frequency band 20 kHz, ranging from -1.0 to +1.0",
+      g_param_spec_double ("band2", "11 kHz",
+          "gain for the frequency band 11 kHz, ranging from -1.0 to +1.0",
           -1.0, 1.0, 0.0, G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE));
 }
 
diff --git a/gst/equalizer/gstiirequalizernbands.c b/gst/equalizer/gstiirequalizernbands.c
index 788dded8..b6482f6e 100644
--- a/gst/equalizer/gstiirequalizernbands.c
+++ b/gst/equalizer/gstiirequalizernbands.c
@@ -28,9 +28,9 @@
  * </para>
  * <para>
  * <programlisting>
- * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audioconvert ! equalizer-nbands num-bands=15 band5::gain=-1.0 ! alsasink
+ * gst-launch filesrc location=song.ogg ! oggdemux ! vorbisdec ! audioconvert ! equalizer-nbands num-bands=15 band5::gain=1.0 ! alsasink
  * </programlisting>
- * This make the equalizer use 15 bands and lowers the volume of the 5th band by FIXME db.
+ * This make the equalizer use 15 bands and raises the volume of the 5th band by 6 db.
  * </para>
  * </refsect2>
  */