--- /dev/null
+/* 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 #playbin2.
+ * </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
+ *
+ * Since: 0.10.25
+ */
+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
+ *
+ * Since: 0.10.25
+ */
+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
+ *
+ * Since: 0.10.25
+ */
+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
+ *
+ * Since: 0.10.25
+ */
+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
+ *
+ * Since: 0.10.25
+ */
+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);
+}
projects / mafwsubrenderer / blobdiff