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373 lines
11 KiB
C
373 lines
11 KiB
C
/* -*- 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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* 2007-2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
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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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*/
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/**
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* SECTION:element-audiowsinclimit
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*
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* Attenuates all frequencies above the cutoff frequency (low-pass) or all frequencies below the
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* cutoff frequency (high-pass). The length parameter controls the rolloff, the window parameter
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* controls rolloff and stopband attenuation. The Hamming window provides a faster rolloff but a bit
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* worse stopband attenuation, the other way around for the Blackman window.
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*
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* This element has the advantage over the Chebyshev lowpass and highpass filter that it has
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* a much better rolloff when using a larger kernel size and almost linear phase. The only
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* disadvantage is the much slower execution time with larger kernels.
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*
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* <refsect2>
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* <title>Example launch line</title>
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* |[
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* gst-launch audiotestsrc freq=1500 ! audioconvert ! audiowsinclimit mode=low-pass frequency=1000 length=501 ! audioconvert ! alsasink
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* gst-launch filesrc location="melo1.ogg" ! oggdemux ! vorbisdec ! audioconvert ! audiowsinclimit mode=high-pass frequency=15000 length=501 ! audioconvert ! alsasink
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* gst-launch audiotestsrc wave=white-noise ! audioconvert ! audiowsinclimit mode=low-pass frequency=1000 length=10001 window=blackman ! audioconvert ! alsasink
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* ]|
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* </refsect2>
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <string.h>
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#include <math.h>
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#include <gst/gst.h>
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#include <gst/audio/gstaudiofilter.h>
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#include <gst/controller/gstcontroller.h>
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#include "audiowsinclimit.h"
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#define GST_CAT_DEFAULT gst_audio_wsinclimit_debug
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GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
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enum
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{
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PROP_0,
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PROP_LENGTH,
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PROP_FREQUENCY,
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PROP_MODE,
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PROP_WINDOW
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};
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enum
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{
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MODE_LOW_PASS = 0,
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MODE_HIGH_PASS
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};
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#define GST_TYPE_AUDIO_WSINC_LIMIT_MODE (gst_audio_wsinclimit_mode_get_type ())
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static GType
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gst_audio_wsinclimit_mode_get_type (void)
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{
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static GType gtype = 0;
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if (gtype == 0) {
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static const GEnumValue values[] = {
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{MODE_LOW_PASS, "Low pass (default)",
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"low-pass"},
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{MODE_HIGH_PASS, "High pass",
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"high-pass"},
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{0, NULL, NULL}
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};
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gtype = g_enum_register_static ("GstAudioWSincLimitMode", values);
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}
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return gtype;
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}
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enum
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{
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WINDOW_HAMMING = 0,
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WINDOW_BLACKMAN
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};
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#define GST_TYPE_AUDIO_WSINC_LIMIT_WINDOW (gst_audio_wsinclimit_window_get_type ())
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static GType
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gst_audio_wsinclimit_window_get_type (void)
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{
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static GType gtype = 0;
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if (gtype == 0) {
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static const GEnumValue values[] = {
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{WINDOW_HAMMING, "Hamming window (default)",
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"hamming"},
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{WINDOW_BLACKMAN, "Blackman window",
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"blackman"},
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{0, NULL, NULL}
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};
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gtype = g_enum_register_static ("GstAudioWSincLimitWindow", values);
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}
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return gtype;
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}
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#define DEBUG_INIT(bla) \
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GST_DEBUG_CATEGORY_INIT (gst_audio_wsinclimit_debug, "audiowsinclimit", 0, \
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"Low-pass and High-pass Windowed sinc filter plugin");
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GST_BOILERPLATE_FULL (GstAudioWSincLimit, gst_audio_wsinclimit, GstAudioFilter,
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GST_TYPE_AUDIO_FX_BASE_FIR_FILTER, DEBUG_INIT);
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static void gst_audio_wsinclimit_set_property (GObject * object, guint prop_id,
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const GValue * value, GParamSpec * pspec);
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static void gst_audio_wsinclimit_get_property (GObject * object, guint prop_id,
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GValue * value, GParamSpec * pspec);
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static void gst_audio_wsinclimit_finalize (GObject * object);
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static gboolean gst_audio_wsinclimit_setup (GstAudioFilter * base,
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GstRingBufferSpec * format);
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/* Element class */
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static void
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gst_audio_wsinclimit_base_init (gpointer g_class)
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{
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GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
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gst_element_class_set_details_simple (element_class,
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"Low pass & high pass filter", "Filter/Effect/Audio",
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"Low pass and high pass windowed sinc filter",
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"Thomas Vander Stichele <thomas at apestaart dot org>, "
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"Steven W. Smith, "
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"Dreamlab Technologies Ltd. <mathis.hofer@dreamlab.net>, "
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"Sebastian Dröge <sebastian.droege@collabora.co.uk>");
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}
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static void
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gst_audio_wsinclimit_class_init (GstAudioWSincLimitClass * klass)
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{
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GObjectClass *gobject_class = (GObjectClass *) klass;
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GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;
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gobject_class->set_property = gst_audio_wsinclimit_set_property;
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gobject_class->get_property = gst_audio_wsinclimit_get_property;
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gobject_class->finalize = gst_audio_wsinclimit_finalize;
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/* FIXME: Don't use the complete possible range but restrict the upper boundary
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* so automatically generated UIs can use a slider */
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g_object_class_install_property (gobject_class, PROP_FREQUENCY,
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g_param_spec_float ("cutoff", "Cutoff",
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"Cut-off Frequency (Hz)", 0.0, 100000.0, 0.0,
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G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (gobject_class, PROP_LENGTH,
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g_param_spec_int ("length", "Length",
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"Filter kernel length, will be rounded to the next odd number",
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3, 256000, 101,
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G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (gobject_class, PROP_MODE,
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g_param_spec_enum ("mode", "Mode",
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"Low pass or high pass mode", GST_TYPE_AUDIO_WSINC_LIMIT_MODE,
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MODE_LOW_PASS,
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G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
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g_object_class_install_property (gobject_class, PROP_WINDOW,
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g_param_spec_enum ("window", "Window",
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"Window function to use", GST_TYPE_AUDIO_WSINC_LIMIT_WINDOW,
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WINDOW_HAMMING,
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G_PARAM_READWRITE | GST_PARAM_CONTROLLABLE | G_PARAM_STATIC_STRINGS));
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filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_wsinclimit_setup);
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}
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static void
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gst_audio_wsinclimit_init (GstAudioWSincLimit * self,
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GstAudioWSincLimitClass * g_class)
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{
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self->mode = MODE_LOW_PASS;
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self->window = WINDOW_HAMMING;
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self->kernel_length = 101;
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self->cutoff = 0.0;
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self->lock = g_mutex_new ();
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}
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static void
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gst_audio_wsinclimit_build_kernel (GstAudioWSincLimit * self)
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{
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gint i = 0;
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gdouble sum = 0.0;
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gint len = 0;
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gdouble w;
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gdouble *kernel = NULL;
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len = self->kernel_length;
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if (GST_AUDIO_FILTER (self)->format.rate == 0) {
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GST_DEBUG ("rate not set yet");
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return;
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}
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if (GST_AUDIO_FILTER (self)->format.channels == 0) {
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GST_DEBUG ("channels not set yet");
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return;
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}
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/* Clamp cutoff frequency between 0 and the nyquist frequency */
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self->cutoff =
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CLAMP (self->cutoff, 0.0, GST_AUDIO_FILTER (self)->format.rate / 2);
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GST_DEBUG ("gst_audio_wsinclimit_: initializing filter kernel of length %d "
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"with cutoff %.2lf Hz "
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"for mode %s",
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len, self->cutoff,
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(self->mode == MODE_LOW_PASS) ? "low-pass" : "high-pass");
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/* fill the kernel */
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w = 2 * G_PI * (self->cutoff / GST_AUDIO_FILTER (self)->format.rate);
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kernel = g_new (gdouble, len);
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for (i = 0; i < len; ++i) {
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if (i == len / 2)
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kernel[i] = w;
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else
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kernel[i] = sin (w * (i - len / 2)) / (i - len / 2);
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/* windowing */
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if (self->window == WINDOW_HAMMING)
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kernel[i] *= (0.54 - 0.46 * cos (2 * G_PI * i / len));
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else
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kernel[i] *= (0.42 - 0.5 * cos (2 * G_PI * i / len) +
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0.08 * cos (4 * G_PI * i / len));
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}
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/* normalize for unity gain at DC */
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for (i = 0; i < len; ++i)
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sum += kernel[i];
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for (i = 0; i < len; ++i)
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kernel[i] /= sum;
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/* convert to highpass if specified */
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if (self->mode == MODE_HIGH_PASS) {
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for (i = 0; i < len; ++i)
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kernel[i] = -kernel[i];
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kernel[len / 2] += 1.0;
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}
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gst_audio_fx_base_fir_filter_set_kernel (GST_AUDIO_FX_BASE_FIR_FILTER (self),
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kernel, self->kernel_length, (len - 1) / 2);
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}
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/* GstAudioFilter vmethod implementations */
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/* get notified of caps and plug in the correct process function */
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static gboolean
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gst_audio_wsinclimit_setup (GstAudioFilter * base, GstRingBufferSpec * format)
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{
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GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (base);
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gst_audio_wsinclimit_build_kernel (self);
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return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, format);
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}
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static void
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gst_audio_wsinclimit_finalize (GObject * object)
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{
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GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (object);
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g_mutex_free (self->lock);
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self->lock = NULL;
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G_OBJECT_CLASS (parent_class)->finalize (object);
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}
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static void
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gst_audio_wsinclimit_set_property (GObject * object, guint prop_id,
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const GValue * value, GParamSpec * pspec)
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{
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GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (object);
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g_return_if_fail (GST_IS_AUDIO_WSINC_LIMIT (self));
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switch (prop_id) {
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case PROP_LENGTH:{
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gint val;
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g_mutex_lock (self->lock);
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val = g_value_get_int (value);
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if (val % 2 == 0)
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val++;
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if (val != self->kernel_length) {
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gst_audio_fx_base_fir_filter_push_residue (GST_AUDIO_FX_BASE_FIR_FILTER
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(self));
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self->kernel_length = val;
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gst_audio_wsinclimit_build_kernel (self);
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}
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g_mutex_unlock (self->lock);
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break;
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}
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case PROP_FREQUENCY:
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g_mutex_lock (self->lock);
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self->cutoff = g_value_get_float (value);
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gst_audio_wsinclimit_build_kernel (self);
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g_mutex_unlock (self->lock);
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break;
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case PROP_MODE:
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g_mutex_lock (self->lock);
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self->mode = g_value_get_enum (value);
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gst_audio_wsinclimit_build_kernel (self);
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g_mutex_unlock (self->lock);
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break;
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case PROP_WINDOW:
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g_mutex_lock (self->lock);
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self->window = g_value_get_enum (value);
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gst_audio_wsinclimit_build_kernel (self);
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g_mutex_unlock (self->lock);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static void
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gst_audio_wsinclimit_get_property (GObject * object, guint prop_id,
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GValue * value, GParamSpec * pspec)
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{
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GstAudioWSincLimit *self = GST_AUDIO_WSINC_LIMIT (object);
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switch (prop_id) {
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case PROP_LENGTH:
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g_value_set_int (value, self->kernel_length);
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break;
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case PROP_FREQUENCY:
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g_value_set_float (value, self->cutoff);
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break;
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case PROP_MODE:
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g_value_set_enum (value, self->mode);
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break;
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case PROP_WINDOW:
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g_value_set_enum (value, self->window);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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