gstreamer/gst/audiofx/audiowsincband.h

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/* -*- c-basic-offset: 2 -*-
*
* GStreamer
* Copyright (C) 1999-2001 Erik Walthinsen <omega@cse.ogi.edu>
* 2006 Dreamlab Technologies Ltd. <mathis.hofer@dreamlab.net>
*
* 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.
*
*
* this windowed sinc filter is taken from the freely downloadable DSP book,
* "The Scientist and Engineer's Guide to Digital Signal Processing",
* chapter 16
* available at http://www.dspguide.com/
*
* FIXME:
* - this filter is totally unoptimized !
* - we do not destroy the allocated memory for filters and residue
* - this might be improved upon with bytestream
*/
#ifndef __GST_BPWSINC_H__
#define __GST_BPWSINC_H__
#include "gstfilter.h"
#include <gst/gst.h>
#include <gst/base/gstbasetransform.h>
G_BEGIN_DECLS
#define GST_TYPE_BPWSINC \
(gst_bpwsinc_get_type())
#define GST_BPWSINC(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BPWSINC,GstBPWSinc))
#define GST_BPWSINC_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_BPWSINC,GstBPWSincClass))
#define GST_IS_BPWSINC(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BPWSINC))
#define GST_IS_BPWSINC_CLASS(klass) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_BPWSINC))
typedef struct _GstBPWSinc GstBPWSinc;
typedef struct _GstBPWSincClass GstBPWSincClass;
/**
* GstBPWSinc:
*
* Opaque data structure.
*/
struct _GstBPWSinc {
GstBaseTransform element;
double frequency;
double lower_frequency, upper_frequency;
int wing_size; /* length of a "wing" of the filter;
actual length is 2 * wing_size + 1 */
gfloat *residue; /* buffer for left-over samples from previous buffer */
double *kernel;
};
struct _GstBPWSincClass {
GstBaseTransformClass parent_class;
};
G_END_DECLS
#endif /* __GST_BPWSINC_H__ */