gstreamer/ext/alsa/gstalsamixerelement.c

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/* ALSA mixer implementation.
* Copyright (C) 2003 Leif Johnson <leif@ambient.2y.net>
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstalsamixerelement.h"
static GstElementDetails gst_alsa_mixer_element_details =
GST_ELEMENT_DETAILS ("Alsa Mixer",
"Generic/Audio",
"Control sound input and output levels with ALSA",
"Leif Johnson <leif@ambient.2y.net>");
GST_BOILERPLATE_WITH_INTERFACE (GstAlsaMixerElement, gst_alsa_mixer_element,
GstElement, GST_TYPE_ELEMENT, GstMixer, GST_TYPE_MIXER,
gst_alsa_mixer_element);
GST_IMPLEMENT_ALSA_MIXER_METHODS (GstAlsaMixerElement, gst_alsa_mixer_element);
static GstStateChangeReturn gst_alsa_mixer_element_change_state (GstElement *
element, GstStateChange transition);
static void
gst_alsa_mixer_element_base_init (gpointer klass)
{
gst_element_class_set_details (GST_ELEMENT_CLASS (klass),
&gst_alsa_mixer_element_details);
}
static void
gst_alsa_mixer_element_class_init (GstAlsaMixerElementClass * klass)
{
GstElementClass *element_class;
element_class = (GstElementClass *) klass;
element_class->change_state = gst_alsa_mixer_element_change_state;
}
static void
gst_alsa_mixer_element_init (GstAlsaMixerElement * this,
GstAlsaMixerElementClass * klass)
{
this->mixer = NULL;
}
static GstStateChangeReturn
gst_alsa_mixer_element_change_state (GstElement * element,
GstStateChange transition)
{
GstAlsaMixerElement *this = GST_ALSA_MIXER_ELEMENT (element);
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
if (!this->mixer) {
this->mixer = gst_alsa_mixer_new ("hw:0", GST_ALSA_MIXER_ALL);
}
break;
case GST_STATE_CHANGE_READY_TO_NULL:
if (this->mixer) {
gst_alsa_mixer_free (this->mixer);
this->mixer = NULL;
}
break;
default:
break;
}
if (GST_ELEMENT_CLASS (parent_class)->change_state)
return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
return GST_STATE_CHANGE_SUCCESS;
}