Port GstSpectrum to GstAudioFilter and libgstfft, add support for int32, float and double, use floats for the message...

Original commit message from CVS:
* configure.ac:
* gst/spectrum/Makefile.am:
* gst/spectrum/demo-audiotest.c: (draw_spectrum),
(message_handler), (main):
* gst/spectrum/demo-osssrc.c: (draw_spectrum), (message_handler):
* gst/spectrum/gstspectrum.c: (gst_spectrum_base_init),
(gst_spectrum_class_init), (gst_spectrum_init),
(gst_spectrum_dispose), (gst_spectrum_set_property),
(gst_spectrum_get_property), (gst_spectrum_start),
(gst_spectrum_setup), (gst_spectrum_message_new),
(gst_spectrum_transform_ip):
* gst/spectrum/gstspectrum.h:
Port GstSpectrum to GstAudioFilter and libgstfft, add support
for int32, float and double, use floats for the message contents,
average all FFTs done in one interval for better results, use
a better windowing function, allow posting the phase in the message
and actually do an FFT with the requested number of bands instead
of interpolating.
* tests/check/elements/spectrum.c: (GST_START_TEST),
(spectrum_suite):
Improve the units tests by checking for a 11025Hz sine wave
and add unit tests for all 4 supported sample types.

3 files changed, 387 insertions, 30 deletions

diff --git a/tests/check/elements/spectrum.c b/tests/check/elements/spectrum.c
index 7e3d1e10..7dee5fe1 100644
--- a/tests/check/elements/spectrum.c
+++ b/tests/check/elements/spectrum.c
@@ -33,24 +33,59 @@ gboolean have_eos = FALSE;
 GstPad *mysrcpad, *mysinkpad;
 
 #define SPECT_CAPS_TEMPLATE_STRING \
+    "audio/x-raw-int, "                                               \
+    " width = (int) 16, "                                             \
+    " depth = (int) 16, "                                             \
+    " signed = (boolean) true, "                                      \
+    " endianness = (int) BYTE_ORDER, "                                \
+    " rate = (int) [ 1, MAX ], "                                      \
+    " channels = (int) [ 1, MAX ]; "                                  \
+    "audio/x-raw-int, "                                               \
+    " width = (int) 32, "                                             \
+    " depth = (int) 32, "                                             \
+    " signed = (boolean) true, "                                      \
+    " endianness = (int) BYTE_ORDER, "                                \
+    " rate = (int) [ 1, MAX ], "                                      \
+    " channels = (int) [ 1, MAX ]; "                                  \
+    "audio/x-raw-float, "                                             \
+    " width = (int) { 32, 64 }, "                                     \
+    " endianness = (int) BYTE_ORDER, "                                \
+    " rate = (int) [ 1, MAX ], "                                      \
+    " channels = (int) [ 1, MAX ]"
+
+#define SPECT_CAPS_STRING_S16 \
   "audio/x-raw-int, " \
-    "rate = (int) [ 1, MAX ], " \
-    "channels = (int) [ 1, 8 ], " \
+    "rate = (int) 44100, " \
+    "channels = (int) 1, " \
     "endianness = (int) BYTE_ORDER, " \
-    "width = (int) {8, 16}, " \
-    "depth = (int) {8, 16}, " \
+    "width = (int) 16, " \
+    "depth = (int) 16, " \
     "signed = (boolean) true"
 
-#define SPECT_CAPS_STRING \
+#define SPECT_CAPS_STRING_S32 \
   "audio/x-raw-int, " \
     "rate = (int) 44100, " \
     "channels = (int) 1, " \
     "endianness = (int) BYTE_ORDER, " \
-    "width = (int) 16, " \
-    "depth = (int) 16, " \
+    "width = (int) 32, " \
+    "depth = (int) 32, " \
     "signed = (boolean) true"
 
-#define SPECT_BANDS 64
+#define SPECT_CAPS_STRING_F32 \
+    "audio/x-raw-float, "                                             \
+    " width = (int) 32, "                                             \
+    " endianness = (int) BYTE_ORDER, "                                \
+    " rate = (int) 44100, "                                           \
+    " channels = (int) 1"
+
+#define SPECT_CAPS_STRING_F64 \
+    "audio/x-raw-float, "                                             \
+    " width = (int) 64, "                                             \
+    " endianness = (int) BYTE_ORDER, "                                \
+    " rate = (int) 44100, "                                           \
+    " channels = (int) 1"
+
+#define SPECT_BANDS 256
 
 static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
@@ -104,24 +139,338 @@ GST_START_TEST (test_int16)
   gint16 *data;
   const GValue *list, *value;
   GstClockTime endtime;
-  guchar level;
+  gfloat level;
 
   spectrum = setup_spectrum ();
-  g_object_set (spectrum, "message", TRUE, "interval", GST_SECOND / 10,
+  g_object_set (spectrum, "message", TRUE, "interval", GST_SECOND / 100,
       "bands", SPECT_BANDS, "threshold", -80, NULL);
 
   fail_unless (gst_element_set_state (spectrum,
           GST_STATE_PLAYING) == GST_STATE_CHANGE_SUCCESS,
       "could not set to playing");
 
-  /* create a fake 1 sec buffer with a half-amplitude block signal */
+  /* create a 1 sec buffer with an 11025 Hz sine wave */
   inbuffer = gst_buffer_new_and_alloc (44100 * sizeof (gint16));
   data = (gint16 *) GST_BUFFER_DATA (inbuffer);
-  for (j = 0; j < 44100; ++j) {
-    *data = 16536;
+
+  for (j = 0; j < 44100; j += 4) {
+    *data = 0;
+    ++data;
+    *data = 32767;
+    ++data;
+    *data = 0;
+    ++data;
+    *data = -32767;
+    ++data;
+  }
+
+  caps = gst_caps_from_string (SPECT_CAPS_STRING_S16);
+  gst_buffer_set_caps (inbuffer, caps);
+  gst_caps_unref (caps);
+  ASSERT_BUFFER_REFCOUNT (inbuffer, "inbuffer", 1);
+
+  /* create a bus to get the spectrum message on */
+  bus = gst_bus_new ();
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 1);
+  gst_element_set_bus (spectrum, bus);
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 2);
+
+  /* pushing gives away my reference ... */
+  fail_unless (gst_pad_push (mysrcpad, inbuffer) == GST_FLOW_OK);
+  /* ... but it ends up being collected on the global buffer list */
+  ASSERT_BUFFER_REFCOUNT (inbuffer, "inbuffer", 1);
+  fail_unless_equals_int (g_list_length (buffers), 1);
+  fail_if ((outbuffer = (GstBuffer *) buffers->data) == NULL);
+  fail_unless (inbuffer == outbuffer);
+
+  message = gst_bus_poll (bus, GST_MESSAGE_ELEMENT, -1);
+  ASSERT_OBJECT_REFCOUNT (message, "message", 1);
+
+  fail_unless (message != NULL);
+  fail_unless (GST_MESSAGE_SRC (message) == GST_OBJECT (spectrum));
+  fail_unless (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ELEMENT);
+  structure = gst_message_get_structure (message);
+  fail_if (structure == NULL);
+  fail_unless_equals_string ((char *) gst_structure_get_name (structure),
+      "spectrum");
+  fail_unless (gst_structure_get_clock_time (structure, "endtime", &endtime));
+
+  list = gst_structure_get_value (structure, "magnitude");
+  for (i = 0; i < SPECT_BANDS; ++i) {
+    value = gst_value_list_get_value (list, i);
+    level = g_value_get_float (value);
+    GST_DEBUG ("band[%3d] is %.2f", i, level);
+    /* Only the bands in the middle should have a level above 60 */
+    fail_if ((i == SPECT_BANDS / 2 || i == SPECT_BANDS / 2 - 1)
+        && level < 60.0);
+    fail_if ((i != SPECT_BANDS / 2 && i != SPECT_BANDS / 2 - 1)
+        && level > 60.0);
+  }
+  fail_unless_equals_int (g_list_length (buffers), 1);
+  fail_if ((outbuffer = (GstBuffer *) buffers->data) == NULL);
+  fail_unless (inbuffer == outbuffer);
+
+  /* clean up */
+  /* flush current messages,and future state change messages */
+  gst_bus_set_flushing (bus, TRUE);
+
+  /* message has a ref to the element */
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 2);
+  gst_message_unref (message);
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 1);
+
+  gst_element_set_bus (spectrum, NULL);
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 1);
+  gst_object_unref (bus);
+  gst_buffer_unref (outbuffer);
+  fail_unless (gst_element_set_state (spectrum,
+          GST_STATE_NULL) == GST_STATE_CHANGE_SUCCESS, "could not set to null");
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 1);
+  cleanup_spectrum (spectrum);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_int32)
+{
+  GstElement *spectrum;
+  GstBuffer *inbuffer, *outbuffer;
+  GstBus *bus;
+  GstCaps *caps;
+  GstMessage *message;
+  const GstStructure *structure;
+  int i, j;
+  gint32 *data;
+  const GValue *list, *value;
+  GstClockTime endtime;
+  gfloat level;
+
+  spectrum = setup_spectrum ();
+  g_object_set (spectrum, "message", TRUE, "interval", GST_SECOND / 100,
+      "bands", SPECT_BANDS, "threshold", -80, NULL);
+
+  fail_unless (gst_element_set_state (spectrum,
+          GST_STATE_PLAYING) == GST_STATE_CHANGE_SUCCESS,
+      "could not set to playing");
+
+  /* create a 1 sec buffer with an 11025 Hz sine wave */
+  inbuffer = gst_buffer_new_and_alloc (44100 * sizeof (gint32));
+  data = (gint32 *) GST_BUFFER_DATA (inbuffer);
+  for (j = 0; j < 44100; j += 4) {
+    *data = 0;
+    ++data;
+    *data = 2147483647;
+    ++data;
+    *data = 0;
+    ++data;
+    *data = -2147483647;
+    ++data;
+  }
+  caps = gst_caps_from_string (SPECT_CAPS_STRING_S32);
+  gst_buffer_set_caps (inbuffer, caps);
+  gst_caps_unref (caps);
+  ASSERT_BUFFER_REFCOUNT (inbuffer, "inbuffer", 1);
+
+  /* create a bus to get the spectrum message on */
+  bus = gst_bus_new ();
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 1);
+  gst_element_set_bus (spectrum, bus);
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 2);
+
+  /* pushing gives away my reference ... */
+  fail_unless (gst_pad_push (mysrcpad, inbuffer) == GST_FLOW_OK);
+  /* ... but it ends up being collected on the global buffer list */
+  ASSERT_BUFFER_REFCOUNT (inbuffer, "inbuffer", 1);
+  fail_unless_equals_int (g_list_length (buffers), 1);
+  fail_if ((outbuffer = (GstBuffer *) buffers->data) == NULL);
+  fail_unless (inbuffer == outbuffer);
+
+  message = gst_bus_poll (bus, GST_MESSAGE_ELEMENT, -1);
+  ASSERT_OBJECT_REFCOUNT (message, "message", 1);
+
+  fail_unless (message != NULL);
+  fail_unless (GST_MESSAGE_SRC (message) == GST_OBJECT (spectrum));
+  fail_unless (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ELEMENT);
+  structure = gst_message_get_structure (message);
+  fail_if (structure == NULL);
+  fail_unless_equals_string ((char *) gst_structure_get_name (structure),
+      "spectrum");
+  fail_unless (gst_structure_get_clock_time (structure, "endtime", &endtime));
+
+  list = gst_structure_get_value (structure, "magnitude");
+  for (i = 0; i < SPECT_BANDS; ++i) {
+    value = gst_value_list_get_value (list, i);
+    level = g_value_get_float (value);
+    GST_DEBUG ("band[%3d] is %.2f", i, level);
+    /* Only the bands in the middle should have a level above 60 */
+    fail_if ((i == SPECT_BANDS / 2 || i == SPECT_BANDS / 2 - 1)
+        && level < 60.0);
+    fail_if ((i != SPECT_BANDS / 2 && i != SPECT_BANDS / 2 - 1)
+        && level > 60.0);
+  }
+  fail_unless_equals_int (g_list_length (buffers), 1);
+  fail_if ((outbuffer = (GstBuffer *) buffers->data) == NULL);
+  fail_unless (inbuffer == outbuffer);
+
+  /* clean up */
+  /* flush current messages,and future state change messages */
+  gst_bus_set_flushing (bus, TRUE);
+
+  /* message has a ref to the element */
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 2);
+  gst_message_unref (message);
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 1);
+
+  gst_element_set_bus (spectrum, NULL);
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 1);
+  gst_object_unref (bus);
+  gst_buffer_unref (outbuffer);
+  fail_unless (gst_element_set_state (spectrum,
+          GST_STATE_NULL) == GST_STATE_CHANGE_SUCCESS, "could not set to null");
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 1);
+  cleanup_spectrum (spectrum);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_float32)
+{
+  GstElement *spectrum;
+  GstBuffer *inbuffer, *outbuffer;
+  GstBus *bus;
+  GstCaps *caps;
+  GstMessage *message;
+  const GstStructure *structure;
+  int i, j;
+  gfloat *data;
+  const GValue *list, *value;
+  GstClockTime endtime;
+  gfloat level;
+
+  spectrum = setup_spectrum ();
+  g_object_set (spectrum, "message", TRUE, "interval", GST_SECOND / 100,
+      "bands", SPECT_BANDS, "threshold", -80, NULL);
+
+  fail_unless (gst_element_set_state (spectrum,
+          GST_STATE_PLAYING) == GST_STATE_CHANGE_SUCCESS,
+      "could not set to playing");
+
+  /* create a 1 sec buffer with an 11025 Hz sine wave */
+  inbuffer = gst_buffer_new_and_alloc (44100 * sizeof (gfloat));
+  data = (gfloat *) GST_BUFFER_DATA (inbuffer);
+  for (j = 0; j < 44100; j += 4) {
+    *data = 0.0;
+    ++data;
+    *data = 1.0;
+    ++data;
+    *data = 0.0;
+    ++data;
+    *data = -1.0;
+    ++data;
+  }
+  caps = gst_caps_from_string (SPECT_CAPS_STRING_F32);
+  gst_buffer_set_caps (inbuffer, caps);
+  gst_caps_unref (caps);
+  ASSERT_BUFFER_REFCOUNT (inbuffer, "inbuffer", 1);
+
+  /* create a bus to get the spectrum message on */
+  bus = gst_bus_new ();
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 1);
+  gst_element_set_bus (spectrum, bus);
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 2);
+
+  /* pushing gives away my reference ... */
+  fail_unless (gst_pad_push (mysrcpad, inbuffer) == GST_FLOW_OK);
+  /* ... but it ends up being collected on the global buffer list */
+  ASSERT_BUFFER_REFCOUNT (inbuffer, "inbuffer", 1);
+  fail_unless_equals_int (g_list_length (buffers), 1);
+  fail_if ((outbuffer = (GstBuffer *) buffers->data) == NULL);
+  fail_unless (inbuffer == outbuffer);
+
+  message = gst_bus_poll (bus, GST_MESSAGE_ELEMENT, -1);
+  ASSERT_OBJECT_REFCOUNT (message, "message", 1);
+
+  fail_unless (message != NULL);
+  fail_unless (GST_MESSAGE_SRC (message) == GST_OBJECT (spectrum));
+  fail_unless (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ELEMENT);
+  structure = gst_message_get_structure (message);
+  fail_if (structure == NULL);
+  fail_unless_equals_string ((char *) gst_structure_get_name (structure),
+      "spectrum");
+  fail_unless (gst_structure_get_clock_time (structure, "endtime", &endtime));
+
+  list = gst_structure_get_value (structure, "magnitude");
+  for (i = 0; i < SPECT_BANDS; ++i) {
+    value = gst_value_list_get_value (list, i);
+    level = g_value_get_float (value);
+    GST_DEBUG ("band[%3d] is %.2f", i, level);
+    /* Only the bands in the middle should have a level above 60 */
+    fail_if ((i == SPECT_BANDS / 2 || i == SPECT_BANDS / 2 - 1)
+        && level < 60.0);
+    fail_if ((i != SPECT_BANDS / 2 && i != SPECT_BANDS / 2 - 1)
+        && level > 60.0);
+  }
+  fail_unless_equals_int (g_list_length (buffers), 1);
+  fail_if ((outbuffer = (GstBuffer *) buffers->data) == NULL);
+  fail_unless (inbuffer == outbuffer);
+
+  /* clean up */
+  /* flush current messages,and future state change messages */
+  gst_bus_set_flushing (bus, TRUE);
+
+  /* message has a ref to the element */
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 2);
+  gst_message_unref (message);
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 1);
+
+  gst_element_set_bus (spectrum, NULL);
+  ASSERT_OBJECT_REFCOUNT (bus, "bus", 1);
+  gst_object_unref (bus);
+  gst_buffer_unref (outbuffer);
+  fail_unless (gst_element_set_state (spectrum,
+          GST_STATE_NULL) == GST_STATE_CHANGE_SUCCESS, "could not set to null");
+  ASSERT_OBJECT_REFCOUNT (spectrum, "spectrum", 1);
+  cleanup_spectrum (spectrum);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_float64)
+{
+  GstElement *spectrum;
+  GstBuffer *inbuffer, *outbuffer;
+  GstBus *bus;
+  GstCaps *caps;
+  GstMessage *message;
+  const GstStructure *structure;
+  int i, j;
+  gdouble *data;
+  const GValue *list, *value;
+  GstClockTime endtime;
+  gfloat level;
+
+  spectrum = setup_spectrum ();
+  g_object_set (spectrum, "message", TRUE, "interval", GST_SECOND / 100,
+      "bands", SPECT_BANDS, "threshold", -80, NULL);
+
+  fail_unless (gst_element_set_state (spectrum,
+          GST_STATE_PLAYING) == GST_STATE_CHANGE_SUCCESS,
+      "could not set to playing");
+
+  /* create a 1 sec buffer with an 11025 Hz sine wave */
+  inbuffer = gst_buffer_new_and_alloc (44100 * sizeof (gdouble));
+  data = (gdouble *) GST_BUFFER_DATA (inbuffer);
+  for (j = 0; j < 44100; j += 4) {
+    *data = 0.0;
+    ++data;
+    *data = 1.0;
+    ++data;
+    *data = 0.0;
+    ++data;
+    *data = -1.0;
     ++data;
   }
-  caps = gst_caps_from_string (SPECT_CAPS_STRING);
+  caps = gst_caps_from_string (SPECT_CAPS_STRING_F64);
   gst_buffer_set_caps (inbuffer, caps);
   gst_caps_unref (caps);
   ASSERT_BUFFER_REFCOUNT (inbuffer, "inbuffer", 1);
@@ -152,13 +501,16 @@ GST_START_TEST (test_int16)
       "spectrum");
   fail_unless (gst_structure_get_clock_time (structure, "endtime", &endtime));
 
-  /* block wave of half amplitude has -5.94 dB for rms, peak and decay */
-  list = gst_structure_get_value (structure, "spectrum");
+  list = gst_structure_get_value (structure, "magnitude");
   for (i = 0; i < SPECT_BANDS; ++i) {
     value = gst_value_list_get_value (list, i);
-    level = g_value_get_uchar (value);
-    GST_DEBUG ("band[%3d] is %3d", i, level);
-    fail_if (level == 0);
+    level = g_value_get_float (value);
+    GST_DEBUG ("band[%3d] is %.2f", i, level);
+    /* Only the bands in the middle should have a level above 60 */
+    fail_if ((i == SPECT_BANDS / 2 || i == SPECT_BANDS / 2 - 1)
+        && level < 60.0);
+    fail_if ((i != SPECT_BANDS / 2 && i != SPECT_BANDS / 2 - 1)
+        && level > 60.0);
   }
   fail_unless_equals_int (g_list_length (buffers), 1);
   fail_if ((outbuffer = (GstBuffer *) buffers->data) == NULL);
@@ -194,6 +546,9 @@ spectrum_suite (void)
 
   suite_add_tcase (s, tc_chain);
   tcase_add_test (tc_chain, test_int16);
+  tcase_add_test (tc_chain, test_int32);
+  tcase_add_test (tc_chain, test_float32);
+  tcase_add_test (tc_chain, test_float64);
 
   return s;
 }
diff --git a/tests/examples/spectrum/demo-audiotest.c b/tests/examples/spectrum/demo-audiotest.c
index edb1d1dc..b9f59ba5 100644
--- a/tests/examples/spectrum/demo-audiotest.c
+++ b/tests/examples/spectrum/demo-audiotest.c
@@ -51,7 +51,7 @@ on_frequency_changed (GtkRange * range, gpointer user_data)
 
 /* draw frequency spectrum as a bunch of bars */
 static void
-draw_spectrum (guchar * data)
+draw_spectrum (gfloat * data)
 {
   gint i;
   GdkRectangle rect = { 0, 0, SPECT_BANDS, 50 };
@@ -78,15 +78,15 @@ message_handler (GstBus * bus, GstMessage * message, gpointer data)
     const gchar *name = gst_structure_get_name (s);
 
     if (strcmp (name, "spectrum") == 0) {
-      guchar spect[SPECT_BANDS];
+      gfloat spect[SPECT_BANDS];
       const GValue *list;
       const GValue *value;
       guint i;
 
-      list = gst_structure_get_value (s, "spectrum");
+      list = gst_structure_get_value (s, "magnitude");
       for (i = 0; i < SPECT_BANDS; ++i) {
         value = gst_value_list_get_value (list, i);
-        spect[i] = g_value_get_uchar (value);
+        spect[i] = g_value_get_float (value);
       }
       draw_spectrum (spect);
     }
@@ -98,7 +98,7 @@ int
 main (int argc, char *argv[])
 {
   GstElement *bin;
-  GstElement *src, *spectrum, *sink;
+  GstElement *src, *spectrum, *audioconvert, *sink;
   GstBus *bus;
   GtkWidget *appwindow, *vbox, *widget;
 
@@ -116,10 +116,12 @@ main (int argc, char *argv[])
   g_object_set (G_OBJECT (spectrum), "bands", SPECT_BANDS, "threshold", -80,
       "message", TRUE, NULL);
 
+  audioconvert = gst_element_factory_make ("audioconvert", "audioconvert");
+
   sink = gst_element_factory_make (DEFAULT_AUDIOSINK, "sink");
 
-  gst_bin_add_many (GST_BIN (bin), src, spectrum, sink, NULL);
-  if (!gst_element_link_many (src, spectrum, sink, NULL)) {
+  gst_bin_add_many (GST_BIN (bin), src, spectrum, audioconvert, sink, NULL);
+  if (!gst_element_link_many (src, spectrum, audioconvert, sink, NULL)) {
     fprintf (stderr, "cant link elements\n");
     exit (1);
   }
diff --git a/tests/examples/spectrum/demo-osssrc.c b/tests/examples/spectrum/demo-osssrc.c
index b71843e6..6c106b26 100644
--- a/tests/examples/spectrum/demo-osssrc.c
+++ b/tests/examples/spectrum/demo-osssrc.c
@@ -43,7 +43,7 @@ on_window_destroy (GtkObject * object, gpointer user_data)
 
 /* draw frequency spectrum as a bunch of bars */
 static void
-draw_spectrum (guchar * data)
+draw_spectrum (gfloat * data)
 {
   gint i;
   GdkRectangle rect = { 0, 0, SPECT_WIDTH, SPECT_HEIGHT };
@@ -70,15 +70,15 @@ message_handler (GstBus * bus, GstMessage * message, gpointer data)
     const gchar *name = gst_structure_get_name (s);
 
     if (strcmp (name, "spectrum") == 0) {
-      guchar spect[SPECT_BANDS];
+      gfloat spect[SPECT_BANDS];
       const GValue *list;
       const GValue *value;
       guint i;
 
-      list = gst_structure_get_value (s, "spectrum");
+      list = gst_structure_get_value (s, "magnitude");
       for (i = 0; i < SPECT_BANDS; ++i) {
         value = gst_value_list_get_value (list, i);
-        spect[i] = g_value_get_uchar (value);
+        spect[i] = g_value_get_float (value);
       }
       draw_spectrum (spect);
     }