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82 lines
2.5 KiB
C
82 lines
2.5 KiB
C
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/* -*- c-basic-offset: 2 -*-
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*
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* GStreamer
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* Copyright (C) 1999-2001 Erik Walthinsen <omega@cse.ogi.edu>
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* 2006 Dreamlab Technologies Ltd. <mathis.hofer@dreamlab.net>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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*
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* this windowed sinc filter is taken from the freely downloadable DSP book,
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* "The Scientist and Engineer's Guide to Digital Signal Processing",
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* chapter 16
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* available at http://www.dspguide.com/
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*
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* FIXME:
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* - this filter is totally unoptimized !
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* - we do not destroy the allocated memory for filters and residue
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* - this might be improved upon with bytestream
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*/
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#ifndef __GST_LPWSINC_H__
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#define __GST_LPWSINC_H__
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#include "gstfilter.h"
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#include <gst/gst.h>
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#include <gst/base/gstbasetransform.h>
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G_BEGIN_DECLS
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#define GST_TYPE_LPWSINC \
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(gst_lpwsinc_get_type())
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#define GST_LPWSINC(obj) \
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(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_LPWSINC,GstLPWSinc))
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#define GST_LPWSINC_CLASS(klass) \
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(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_LPWSINC,GstLPWSincClass))
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#define GST_IS_LPWSINC(obj) \
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(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_LPWSINC))
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#define GST_IS_LPWSINC_CLASS(klass) \
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(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_LPWSINC))
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typedef struct _GstLPWSinc GstLPWSinc;
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typedef struct _GstLPWSincClass GstLPWSincClass;
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/**
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* GstLPWSinc:
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*
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* Opaque data structure.
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*/
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struct _GstLPWSinc {
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GstBaseTransform element;
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void (*process)(GstLPWSinc*, gpointer, gint);
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double frequency;
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int wing_size; /* length of a "wing" of the filter;
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actual length is 2 * wing_size + 1 */
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gfloat *residue; /* buffer for left-over samples from previous buffer */
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double *kernel;
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};
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struct _GstLPWSincClass {
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GstBaseTransformClass parent_class;
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};
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G_END_DECLS
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#endif /* __GST_LPWSINC_H__ */
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