--- /dev/null
+/* 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_fft_guts_f32.h"
+#include "kiss_fftr_f32.h"
+#include "gstfft.h"
+#include "gstfftf32.h"
+
+/**
+ * SECTION:gstfftf32
+ * @short_description: FFT functions for 32 bit float samples
+ *
+ * #GstFFTF32 provides a FFT implementation and related functions for
+ * 32 bit float samples. To use this call gst_fft_f32_new() for
+ * allocating a #GstFFTF32 instance with the appropiate parameters and
+ * then call gst_fft_f32_fft() or gst_fft_f32_inverse_fft() to perform the
+ * FFT or inverse FFT on a buffer of samples.
+ *
+ * After use free the #GstFFTF32 instance with gst_fft_f32_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_f32_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_f32_window() can comfortably
+ * be used.
+ *
+ * Be aware, that you can't simply run gst_fft_f32_inverse_fft() on the
+ * resulting frequency data of gst_fft_f32_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_f32_new:
+ * @len: Length of the FFT in the time domain
+ * @inverse: %TRUE if the #GstFFTF32 instance should be used for the inverse FFT
+ *
+ * This returns a new #GstFFTF32 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 #GstFFTF32 instance.
+ */
+GstFFTF32 *
+gst_fft_f32_new (gint len, gboolean inverse)
+{
+ GstFFTF32 *self;
+ gsize subsize = 0, memneeded;
+
+ g_return_val_if_fail (len > 0, NULL);
+ g_return_val_if_fail (len % 2 == 0, NULL);
+
+ kiss_fftr_f32_alloc (len, (inverse) ? 1 : 0, NULL, &subsize);
+ memneeded = ALIGN_STRUCT (sizeof (GstFFTF32)) + subsize;
+
+ self = (GstFFTF32 *) g_malloc0 (memneeded);
+
+ self->cfg = (((guint8 *) self) + ALIGN_STRUCT (sizeof (GstFFTF32)));
+ self->cfg = kiss_fftr_f32_alloc (len, (inverse) ? 1 : 0, self->cfg, &subsize);
+ g_assert (self->cfg);
+
+ self->inverse = inverse;
+ self->len = len;
+
+ return self;
+}
+
+/**
+ * gst_fft_f32_fft:
+ * @self: #GstFFTF32 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 #GstFFTF32 instance with gst_fft_f32_new().
+ *
+ * @freqdata must be large enough to hold @len/2 + 1 #GstFFTF32Complex frequency
+ * domain samples.
+ *
+ */
+void
+gst_fft_f32_fft (GstFFTF32 * self, const gfloat * timedata,
+ GstFFTF32Complex * freqdata)
+{
+ g_return_if_fail (self);
+ g_return_if_fail (!self->inverse);
+ g_return_if_fail (timedata);
+ g_return_if_fail (freqdata);
+
+ kiss_fftr_f32 (self->cfg, timedata, (kiss_fft_f32_cpx *) freqdata);
+}
+
+/**
+ * gst_fft_f32_inverse_fft:
+ * @self: #GstFFTF32 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 #GstFFTF32 instance with gst_fft_f32_new().
+ *
+ * @timedata must be large enough to hold @len time domain samples.
+ *
+ */
+void
+gst_fft_f32_inverse_fft (GstFFTF32 * self, const GstFFTF32Complex * freqdata,
+ gfloat * timedata)
+{
+ g_return_if_fail (self);
+ g_return_if_fail (self->inverse);
+ g_return_if_fail (timedata);
+ g_return_if_fail (freqdata);
+
+ kiss_fftri_f32 (self->cfg, (kiss_fft_f32_cpx *) freqdata, timedata);
+}
+
+/**
+ * gst_fft_f32_free:
+ * @self: #GstFFTF32 instance for this call
+ *
+ * This frees the memory allocated for @self.
+ *
+ */
+void
+gst_fft_f32_free (GstFFTF32 * self)
+{
+ g_free (self);
+}
+
+/**
+ * gst_fft_f32_window:
+ * @self: #GstFFTF32 instance for this call
+ * @timedata: Time domain samples
+ * @window: Window function to apply
+ *
+ * This calls the window function @window on the @timedata sample buffer.
+ *
+ */
+void
+gst_fft_f32_window (GstFFTF32 * self, gfloat * 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;
+ }
+}
projects / mafwsubrenderer / blobdiff