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/* GStreamer Mixer
* 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gststreamvolume
* @short_description: Interface for elements that provide a stream volume
*
* <refsect2>
* <para>
* This interface is implemented by elements that provide a stream volume. Examples for
* such elements are #volume and #playbin.
* </para>
* <para>
* Applications can use this interface to get or set the current stream volume. For this
* the "volume" #GObject property can be used or the helper functions gst_stream_volume_set_volume()
* and gst_stream_volume_get_volume(). This volume is always a linear factor, i.e. 0.0 is muted
* 1.0 is 100%. For showing the volume in a GUI it might make sense to convert it to
* a different format by using gst_stream_volume_convert_volume(). Volume sliders should usually
* use a cubic volume.
*
* Separate from the volume the stream can also be muted by the "mute" #GObject property or
* gst_stream_volume_set_mute() and gst_stream_volume_get_mute().
* </para>
* <para>
* Elements that provide some kind of stream volume should implement the "volume" and
* "mute" #GObject properties and handle setting and getting of them properly.
* The volume property is defined to be a linear volume factor.
* </para>
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "streamvolume.h"
#include <math.h>
static void
gst_stream_volume_class_init (GstStreamVolumeInterface * iface)
{
g_object_interface_install_property (iface,
g_param_spec_double ("volume",
"Volume",
"Linear volume factor, 1.0=100%",
0.0, G_MAXDOUBLE, 1.0, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_interface_install_property (iface,
g_param_spec_boolean ("mute",
"Mute",
"Mute the audio channel without changing the volume",
FALSE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
}
GType
gst_stream_volume_get_type (void)
{
static volatile gsize type = 0;
if (g_once_init_enter (&type)) {
GType tmp;
static const GTypeInfo info = {
sizeof (GstStreamVolumeInterface),
NULL, /* base_init */
NULL, /* base_finalize */
(GClassInitFunc) gst_stream_volume_class_init, /* class_init */
NULL, /* class_finalize */
NULL, /* class_data */
0,
0, /* n_preallocs */
NULL /* instance_init */
};
tmp = g_type_register_static (G_TYPE_INTERFACE,
"GstStreamVolume", &info, 0);
g_type_interface_add_prerequisite (tmp, G_TYPE_OBJECT);
g_once_init_leave (&type, tmp);
}
return type;
}
/**
* gst_stream_volume_get_volume:
* @volume: #GstStreamVolume that should be used
* @format: #GstStreamVolumeFormat which should be returned
*
* Returns: The current stream volume as linear factor
*/
gdouble
gst_stream_volume_get_volume (GstStreamVolume * volume,
GstStreamVolumeFormat format)
{
gdouble val;
g_return_val_if_fail (GST_IS_STREAM_VOLUME (volume), 1.0);
g_object_get (volume, "volume", &val, NULL);
if (format != GST_STREAM_VOLUME_FORMAT_LINEAR)
val =
gst_stream_volume_convert_volume (GST_STREAM_VOLUME_FORMAT_LINEAR,
format, val);
return val;
}
/**
* gst_stream_volume_set_volume:
* @volume: #GstStreamVolume that should be used
* @format: #GstStreamVolumeFormat of @val
* @val: Linear volume factor that should be set
*/
void
gst_stream_volume_set_volume (GstStreamVolume * volume,
GstStreamVolumeFormat format, gdouble val)
{
g_return_if_fail (GST_IS_STREAM_VOLUME (volume));
if (format != GST_STREAM_VOLUME_FORMAT_LINEAR)
val =
gst_stream_volume_convert_volume (format,
GST_STREAM_VOLUME_FORMAT_LINEAR, val);
g_object_set (volume, "volume", val, NULL);
}
/**
* gst_stream_volume_get_mute:
* @volume: #GstStreamVolume that should be used
*
* Returns: Returns %TRUE if the stream is muted
*/
gboolean
gst_stream_volume_get_mute (GstStreamVolume * volume)
{
gboolean val;
g_return_val_if_fail (GST_IS_STREAM_VOLUME (volume), FALSE);
g_object_get (volume, "mute", &val, NULL);
return val;
}
/**
* gst_stream_volume_set_mute:
* @volume: #GstStreamVolume that should be used
* @mute: Mute state that should be set
*/
void
gst_stream_volume_set_mute (GstStreamVolume * volume, gboolean mute)
{
g_return_if_fail (GST_IS_STREAM_VOLUME (volume));
g_object_set (volume, "mute", mute, NULL);
}
/**
* gst_stream_volume_convert_volume:
* @from: #GstStreamVolumeFormat to convert from
* @to: #GstStreamVolumeFormat to convert to
* @val: Volume in @from format that should be converted
*
* Returns: the converted volume
*/
gdouble
gst_stream_volume_convert_volume (GstStreamVolumeFormat from,
GstStreamVolumeFormat to, gdouble val)
{
switch (from) {
case GST_STREAM_VOLUME_FORMAT_LINEAR:
g_return_val_if_fail (val >= 0.0, 0.0);
switch (to) {
case GST_STREAM_VOLUME_FORMAT_LINEAR:
return val;
case GST_STREAM_VOLUME_FORMAT_CUBIC:
return pow (val, 1 / 3.0);
case GST_STREAM_VOLUME_FORMAT_DB:
return 20.0 * log10 (val);
}
break;
case GST_STREAM_VOLUME_FORMAT_CUBIC:
g_return_val_if_fail (val >= 0.0, 0.0);
switch (to) {
case GST_STREAM_VOLUME_FORMAT_LINEAR:
return val * val * val;
case GST_STREAM_VOLUME_FORMAT_CUBIC:
return val;
case GST_STREAM_VOLUME_FORMAT_DB:
return 3.0 * 20.0 * log10 (val);
}
break;
case GST_STREAM_VOLUME_FORMAT_DB:
switch (to) {
case GST_STREAM_VOLUME_FORMAT_LINEAR:
return pow (10.0, val / 20.0);
case GST_STREAM_VOLUME_FORMAT_CUBIC:
return pow (10.0, val / (3.0 * 20.0));
case GST_STREAM_VOLUME_FORMAT_DB:
return val;
}
break;
}
g_return_val_if_reached (0.0);
}
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