--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_base/gst-libs/gst/fft/gstffts16.c	Fri Jan 22 09:59:59 2010 +0200
@@ -0,0 +1,223 @@
+/* GStreamer
+ * Copyright (C) <2007> Sebastian Dröge <slomo@circular-chaos.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 <glib.h>
+#include <math.h>
+
+#include "kiss_fftr_s16.h"
+#include "gstfft.h"
+#include "gstffts16.h"
+
+/**
+ * SECTION:gstffts16
+ * @short_description: FFT functions for signed 16 bit integer samples
+ *
+ * #GstFFTS16 provides a FFT implementation and related functions for
+ * signed 16 bit integer samples. To use this call gst_fft_s16_new() for
+ * allocating a #GstFFTS16 instance with the appropiate parameters and
+ * then call gst_fft_s16_fft() or gst_fft_s16_inverse_fft() to perform the
+ * FFT or inverse FFT on a buffer of samples.
+ *
+ * After use free the #GstFFTS16 instance with gst_fft_s16_free().
+ *
+ * For the best performance use gst_fft_next_fast_length() to get a
+ * number that is entirely a product of 2, 3 and 5 and use this as the
+ * @len parameter for gst_fft_s16_new().
+ *
+ * The @len parameter specifies the number of samples in the time domain that
+ * will be processed or generated. The number of samples in the frequency domain
+ * is @len/2 + 1. To get n samples in the frequency domain use 2*n - 2 as @len.
+ *
+ * Before performing the FFT on time domain data it usually makes sense
+ * to apply a window function to it. For this gst_fft_s16_window() can comfortably
+ * be used.
+ *
+ * Be aware, that you can't simply run gst_fft_s16_inverse_fft() on the
+ * resulting frequency data of gst_fft_s16_fft() to get the original data back.
+ * The relation between them is iFFT (FFT (x)) = x / nfft where nfft is the
+ * length of the FFT. This also has to be taken into account when calculation
+ * the magnitude of the frequency data.
+ * 
+ */
+
+/**
+ * gst_fft_s16_new:
+ * @len: Length of the FFT in the time domain
+ * @inverse: %TRUE if the #GstFFTS16 instance should be used for the inverse FFT
+ *
+ * This returns a new #GstFFTS16 instance with the given parameters. It makes
+ * sense to keep one instance for several calls for speed reasons.
+ *
+ * @len must be even and to get the best performance a product of
+ * 2, 3 and 5. To get the next number with this characteristics use
+ * gst_fft_next_fast_length().
+ *
+ * Returns: a new #GstFFTS16 instance.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstFFTS16 *
+gst_fft_s16_new (gint len, gboolean inverse)
+{
+  GstFFTS16 *self;
+
+  g_return_val_if_fail (len > 0, NULL);
+  g_return_val_if_fail (len % 2 == 0, NULL);
+
+  self = g_new (GstFFTS16, 1);
+
+  self->cfg = kiss_fftr_s16_alloc (len, (inverse) ? 1 : 0, NULL, NULL);
+  g_assert (self->cfg);
+
+  self->inverse = inverse;
+  self->len = len;
+
+  return self;
+}
+
+/**
+ * gst_fft_s16_fft:
+ * @self: #GstFFTS16 instance for this call
+ * @timedata: Buffer of the samples in the time domain
+ * @freqdata: Target buffer for the samples in the frequency domain
+ *
+ * This performs the FFT on @timedata and puts the result in @freqdata.
+ *
+ * @timedata must have as many samples as specified with the @len parameter while
+ * allocating the #GstFFTS16 instance with gst_fft_s16_new().
+ *
+ * @freqdata must be large enough to hold @len/2 + 1 #GstFFTS16Complex frequency
+ * domain samples.
+ *
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_fft_s16_fft (GstFFTS16 * self, const gint16 * timedata,
+    GstFFTS16Complex * freqdata)
+{
+  g_return_if_fail (self);
+  g_return_if_fail (!self->inverse);
+  g_return_if_fail (timedata);
+  g_return_if_fail (freqdata);
+
+  kiss_fftr_s16 (self->cfg, timedata, (kiss_fft_s16_cpx *) freqdata);
+}
+
+/**
+ * gst_fft_s16_inverse_fft:
+ * @self: #GstFFTS16 instance for this call
+ * @freqdata: Buffer of the samples in the frequency domain
+ * @timedata: Target buffer for the samples in the time domain
+ *
+ * This performs the inverse FFT on @freqdata and puts the result in @timedata.
+ *
+ * @freqdata must have @len/2 + 1 samples, where @len is the parameter specified
+ * while allocating the #GstFFTS16 instance with gst_fft_s16_new().
+ *
+ * @timedata must be large enough to hold @len time domain samples.
+ *
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_fft_s16_inverse_fft (GstFFTS16 * self, const GstFFTS16Complex * freqdata,
+    gint16 * timedata)
+{
+  g_return_if_fail (self);
+  g_return_if_fail (self->inverse);
+  g_return_if_fail (timedata);
+  g_return_if_fail (freqdata);
+
+  kiss_fftri_s16 (self->cfg, (kiss_fft_s16_cpx *) freqdata, timedata);
+}
+
+/**
+ * gst_fft_s16_free:
+ * @self: #GstFFTS16 instance for this call
+ *
+ * This frees the memory allocated for @self.
+ *
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_fft_s16_free (GstFFTS16 * self)
+{
+  kiss_fftr_s16_free (self->cfg);
+  g_free (self);
+}
+
+/**
+ * gst_fft_s16_window:
+ * @self: #GstFFTS16 instance for this call
+ * @timedata: Time domain samples
+ * @window: Window function to apply
+ *
+ * This calls the window function @window on the @timedata sample buffer.
+ *
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_fft_s16_window (GstFFTS16 * self, gint16 * timedata, GstFFTWindow window)
+{
+  gint i, len;
+
+  g_return_if_fail (self);
+  g_return_if_fail (timedata);
+
+  len = self->len;
+
+  switch (window) {
+    case GST_FFT_WINDOW_RECTANGULAR:
+      /* do nothing */
+      break;
+    case GST_FFT_WINDOW_HAMMING:
+      for (i = 0; i < len; i++)
+        timedata[i] *= (0.53836 - 0.46164 * cos (2.0 * M_PI * i / len));
+      break;
+    case GST_FFT_WINDOW_HANN:
+      for (i = 0; i < len; i++)
+        timedata[i] *= (0.5 - 0.5 * cos (2.0 * M_PI * i / len));
+      break;
+    case GST_FFT_WINDOW_BARTLETT:
+      for (i = 0; i < len; i++)
+        timedata[i] *= (1.0 - fabs ((2.0 * i - len) / len));
+      break;
+    case GST_FFT_WINDOW_BLACKMAN:
+      for (i = 0; i < len; i++)
+        timedata[i] *= (0.42 - 0.5 * cos ((2.0 * i) / len) +
+            0.08 * cos ((4.0 * i) / len));
+      break;
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+}