/* 

 * GStreamer

 * Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>

 *

 * 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., 51 Franklin St, Fifth Floor,

 * Boston, MA 02110-1301, USA.

 * 

 */

/**

 * SECTION:element-audiofirfilter

 *

 * audiofirfilter implements a generic audio <ulink url="http://en.wikipedia.org/wiki/Finite_impulse_response">FIR filter</ulink>. Before usage the

 * "kernel" property has to be set to the filter kernel that should be

 * used and the "latency" property has to be set to the latency (in samples)

 * that is introduced by the filter kernel. Setting a latency of n samples

 * will lead to the first n samples being dropped from the output and

 * n samples added to the end.

 *

 * The filter kernel describes the impulse response of the filter. To

 * calculate the frequency response of the filter you have to calculate

 * the Fourier Transform of the impulse response.

 *

 * To change the filter kernel whenever the sampling rate changes the

 * "rate-changed" signal can be used. This should be done for most

 * FIR filters as they're depending on the sampling rate.

 *

 * <refsect2>

 * <title>Example application</title>

 * <informalexample><programlisting language="C">

 * <xi:include xmlns:xi="http://www.w3.org/2003/XInclude" parse="text" href="../../../../tests/examples/audiofx/firfilter-example.c" />

 * </programlisting></informalexample>

 * </refsect2>

 */

/* FIXME 0.11: suppress warnings for deprecated API such as GValueArray

 * with newer GLib versions (>= 2.31.0) */

#define GLIB_DISABLE_DEPRECATION_WARNINGS

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <string.h>

#include <math.h>

#include <gst/gst.h>

#include <gst/audio/gstaudiofilter.h>

#include "audiofirfilter.h"

#include "gst/glib-compat-private.h"

#define GST_CAT_DEFAULT gst_audio_fir_filter_debug

GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

enum

{

  SIGNAL_RATE_CHANGED,

  LAST_SIGNAL

};

enum

{

  PROP_0,

  PROP_KERNEL,

  PROP_LATENCY

};

static guint gst_audio_fir_filter_signals[LAST_SIGNAL] = { 0, };

#define gst_audio_fir_filter_parent_class parent_class

G_DEFINE_TYPE (GstAudioFIRFilter, gst_audio_fir_filter,

    GST_TYPE_AUDIO_FX_BASE_FIR_FILTER);

static void gst_audio_fir_filter_set_property (GObject * object, guint prop_id,

    const GValue * value, GParamSpec * pspec);

static void gst_audio_fir_filter_get_property (GObject * object, guint prop_id,

    GValue * value, GParamSpec * pspec);

static void gst_audio_fir_filter_finalize (GObject * object);

static gboolean gst_audio_fir_filter_setup (GstAudioFilter * base,

    const GstAudioInfo * info);

static void

gst_audio_fir_filter_class_init (GstAudioFIRFilterClass * klass)

{

  GObjectClass *gobject_class = (GObjectClass *) klass;

  GstElementClass *gstelement_class = (GstElementClass *) klass;

  GstAudioFilterClass *filter_class = (GstAudioFilterClass *) klass;

  GST_DEBUG_CATEGORY_INIT (gst_audio_fir_filter_debug, "audiofirfilter", 0,

      "Generic audio FIR filter plugin");

  gobject_class->set_property = gst_audio_fir_filter_set_property;

  gobject_class->get_property = gst_audio_fir_filter_get_property;

  gobject_class->finalize = gst_audio_fir_filter_finalize;

  g_object_class_install_property (gobject_class, PROP_KERNEL,

      g_param_spec_value_array ("kernel", "Filter Kernel",

          "Filter kernel for the FIR filter",

          g_param_spec_double ("Element", "Filter Kernel Element",

              "Element of the filter kernel", -G_MAXDOUBLE, G_MAXDOUBLE, 0.0,

              G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS),

          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class, PROP_LATENCY,

      g_param_spec_uint64 ("latency", "Latecy",

          "Filter latency in samples",

          0, G_MAXUINT64, 0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  filter_class->setup = GST_DEBUG_FUNCPTR (gst_audio_fir_filter_setup);

  /**

   * GstAudioFIRFilter::rate-changed:

   * @filter: the filter on which the signal is emitted

   * @rate: the new sampling rate

   *

   * Will be emitted when the sampling rate changes. The callbacks

   * will be called from the streaming thread and processing will

   * stop until the event is handled.

   */

  gst_audio_fir_filter_signals[SIGNAL_RATE_CHANGED] =

      g_signal_new ("rate-changed", G_TYPE_FROM_CLASS (klass),

      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAudioFIRFilterClass, rate_changed),

      NULL, NULL, NULL, G_TYPE_NONE, 1, G_TYPE_INT);

  gst_element_class_set_static_metadata (gstelement_class,

      "Audio FIR filter", "Filter/Effect/Audio",

      "Generic audio FIR filter with custom filter kernel",

      "Sebastian Dröge <sebastian.droege@collabora.co.uk>");

}

static void

gst_audio_fir_filter_update_kernel (GstAudioFIRFilter * self, GValueArray * va)

{

  gdouble *kernel;

  guint i;

  if (va) {

    if (self->kernel)

      g_value_array_free (self->kernel);

    self->kernel = va;

  }

  kernel = g_new (gdouble, self->kernel->n_values);

  for (i = 0; i < self->kernel->n_values; i++) {

    GValue *v = g_value_array_get_nth (self->kernel, i);

    kernel[i] = g_value_get_double (v);

  }

  gst_audio_fx_base_fir_filter_set_kernel (GST_AUDIO_FX_BASE_FIR_FILTER (self),

      kernel, self->kernel->n_values, self->latency, NULL);

}

static void

gst_audio_fir_filter_init (GstAudioFIRFilter * self)

{

  GValue v = { 0, };

  GValueArray *va;

  self->latency = 0;

  va = g_value_array_new (1);

  g_value_init (&v, G_TYPE_DOUBLE);

  g_value_set_double (&v, 1.0);

  g_value_array_append (va, &v);

  g_value_unset (&v);

  gst_audio_fir_filter_update_kernel (self, va);

  g_mutex_init (&self->lock);

}

/* GstAudioFilter vmethod implementations */

/* get notified of caps and plug in the correct process function */

static gboolean

gst_audio_fir_filter_setup (GstAudioFilter * base, const GstAudioInfo * info)

{

  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (base);

  gint new_rate = GST_AUDIO_INFO_RATE (info);

  if (GST_AUDIO_FILTER_RATE (self) != new_rate) {

    g_signal_emit (G_OBJECT (self),

        gst_audio_fir_filter_signals[SIGNAL_RATE_CHANGED], 0, new_rate);

  }

  return GST_AUDIO_FILTER_CLASS (parent_class)->setup (base, info);

}

static void

gst_audio_fir_filter_finalize (GObject * object)

{

  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (object);

  g_mutex_clear (&self->lock);

  if (self->kernel)

    g_value_array_free (self->kernel);

  self->kernel = NULL;

  G_OBJECT_CLASS (parent_class)->finalize (object);

}

static void

gst_audio_fir_filter_set_property (GObject * object, guint prop_id,

    const GValue * value, GParamSpec * pspec)

{

  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (object);

  g_return_if_fail (GST_IS_AUDIO_FIR_FILTER (self));

  switch (prop_id) {

    case PROP_KERNEL:

      g_mutex_lock (&self->lock);

      /* update kernel already pushes residues */

      gst_audio_fir_filter_update_kernel (self, g_value_dup_boxed (value));

      g_mutex_unlock (&self->lock);

      break;

    case PROP_LATENCY:

      g_mutex_lock (&self->lock);

      self->latency = g_value_get_uint64 (value);

      gst_audio_fir_filter_update_kernel (self, NULL);

      g_mutex_unlock (&self->lock);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

  }

}

static void

gst_audio_fir_filter_get_property (GObject * object, guint prop_id,

    GValue * value, GParamSpec * pspec)

{

  GstAudioFIRFilter *self = GST_AUDIO_FIR_FILTER (object);

  switch (prop_id) {

    case PROP_KERNEL:

      g_value_set_boxed (value, self->kernel);

      break;

    case PROP_LATENCY:

      g_value_set_uint64 (value, self->latency);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

  }

}