gststereo.c

/* GStreamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 *
 * 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 effect is borrowed from xmms-0.6.1, though I mangled it so badly in
 * the process of copying it over that the xmms people probably won't want
 * any credit for it ;-)
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gststereo.h"

/* elementfactory information */
static GstElementDetails stereo_details = GST_ELEMENT_DETAILS ("Stereo effect",
    "Filter/Effect/Audio",
    "Muck with the stereo signal to enhance its 'stereo-ness'",
    "Erik Walthinsen <omega@cse.ogi.edu>");


/* Stereo signals and args */
enum
{
  /* FILL ME */
  LAST_SIGNAL
};

enum
{
  ARG_0,
  ARG_ACTIVE,
  ARG_STEREO
};


static void gst_stereo_base_init (gpointer g_class);
static void gst_stereo_class_init (GstStereoClass * klass);
static void gst_stereo_init (GstStereo * stereo);

static void gst_stereo_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_stereo_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

static void gst_stereo_chain (GstPad * pad, GstData * _data);

static GstElementClass *parent_class = NULL;

/*static guint gst_stereo_signals[LAST_SIGNAL] = { 0 }; */

GType
gst_stereo_get_type (void)
{
  static GType stereo_type = 0;

  if (!stereo_type) {
    static const GTypeInfo stereo_info = {
      sizeof (GstStereoClass),
      gst_stereo_base_init,
      NULL,
      (GClassInitFunc) gst_stereo_class_init,
      NULL,
      NULL,
      sizeof (GstStereo),
      0,
      (GInstanceInitFunc) gst_stereo_init,
    };

    stereo_type =
        g_type_register_static (GST_TYPE_ELEMENT, "GstStereo", &stereo_info, 0);
  }
  return stereo_type;
}

static void
gst_stereo_base_init (gpointer g_class)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_set_details (element_class, &stereo_details);
}
static void
gst_stereo_class_init (GstStereoClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;

  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);

  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_ACTIVE, g_param_spec_int ("active", "active", "active", G_MININT, G_MAXINT, 0, G_PARAM_READWRITE));      /* CHECKME */
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_STEREO, g_param_spec_float ("stereo", "stereo", "stereo", 0.0, 1.0, 0.0, G_PARAM_READWRITE));    /* CHECKME */

  gobject_class->set_property = gst_stereo_set_property;
  gobject_class->get_property = gst_stereo_get_property;
}

static void
gst_stereo_init (GstStereo * stereo)
{
  stereo->sinkpad = gst_pad_new ("sink", GST_PAD_SINK);
  gst_element_add_pad (GST_ELEMENT (stereo), stereo->sinkpad);
  gst_pad_set_chain_function (stereo->sinkpad, gst_stereo_chain);
  stereo->srcpad = gst_pad_new ("src", GST_PAD_SRC);
  gst_element_add_pad (GST_ELEMENT (stereo), stereo->srcpad);

  stereo->active = FALSE;
  stereo->stereo = 2.5;
}

static void
gst_stereo_chain (GstPad * pad, GstData * _data)
{
  GstBuffer *buf = GST_BUFFER (_data);
  GstStereo *stereo;
  gint16 *data;
  gint samples;
  gint i;
  gdouble avg, ldiff, rdiff, tmp, mul;

  g_return_if_fail (pad != NULL);
  g_return_if_fail (GST_IS_PAD (pad));
  g_return_if_fail (buf != NULL);

  stereo = GST_STEREO (GST_OBJECT_PARENT (pad));
  g_return_if_fail (stereo != NULL);
  g_return_if_fail (GST_IS_STEREO (stereo));

/*  FIXME */
/*  if (buf->meta) */
/*    memcpy(&stereo->meta,buf->meta,sizeof(stereo->meta)); */

  if (stereo->active) {

    /*if (stereo->meta.channels == 2 && stereo->meta.format == AFMT_S16_LE) { */
    data = (gint16 *) GST_BUFFER_DATA (buf);
    samples = GST_BUFFER_SIZE (buf) / 2;
    mul = stereo->stereo;
    for (i = 0; i < samples / 2; i += 2) {
      avg = (data[i] + data[i + 1]) / 2;
      ldiff = data[i] - avg;
      rdiff = data[i + 1] - avg;

      tmp = avg + ldiff * mul;
      if (tmp < -32768)
        tmp = -32768;
      if (tmp > 32767)
        tmp = 32767;
      data[i] = tmp;

      tmp = avg + rdiff * mul;
      if (tmp < -32768)
        tmp = -32768;
      if (tmp > 32767)
        tmp = 32767;
      data[i + 1] = tmp;
    }
    /*} */
  }

  gst_pad_push (stereo->srcpad, GST_DATA (buf));
}

static void
gst_stereo_set_property (GObject * object, guint prop_id, const GValue * value,
    GParamSpec * pspec)
{
  GstStereo *stereo;

  /* it's not null if we got it, but it might not be ours */
  g_return_if_fail (GST_IS_STEREO (object));
  stereo = GST_STEREO (object);

  switch (prop_id) {
    case ARG_ACTIVE:
      stereo->active = g_value_get_int (value);
      break;
    case ARG_STEREO:
      stereo->stereo = g_value_get_float (value) * 10.0;
      break;
    default:
      break;
  }
}

static void
gst_stereo_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstStereo *stereo;

  /* it's not null if we got it, but it might not be ours */
  g_return_if_fail (GST_IS_STEREO (object));
  stereo = GST_STEREO (object);

  switch (prop_id) {
    case ARG_ACTIVE:
      g_value_set_int (value, stereo->active);
      break;
    case ARG_STEREO:
      g_value_set_float (value, stereo->stereo / 10.0);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  return gst_element_register (plugin, "stereo", GST_RANK_NONE,
      GST_TYPE_STEREO);
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "stereo",
    "Muck with the stereo signal, enhance it's 'stereo-ness'",
    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE, GST_ORIGIN)