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Description
This interface is implemented by elements that provide a stream volume. Examples for such elements are volume and playbin.
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()
.
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.
Functions
gst_stream_volume_get_volume ()
gdouble gst_stream_volume_get_volume (GstStreamVolume *volume
,GstStreamVolumeFormat format
);
Parameters
volume |
GstStreamVolume that should be used |
|
format |
GstStreamVolumeFormat which should be returned |
gst_stream_volume_set_volume ()
void gst_stream_volume_set_volume (GstStreamVolume *volume
,GstStreamVolumeFormat format
,gdouble val
);
Parameters
volume |
GstStreamVolume that should be used |
|
format |
GstStreamVolumeFormat of |
|
val |
Linear volume factor that should be set |
gst_stream_volume_set_mute ()
void gst_stream_volume_set_mute (GstStreamVolume *volume
,gboolean mute
);
gst_stream_volume_convert_volume ()
gdouble gst_stream_volume_convert_volume (GstStreamVolumeFormat from
,GstStreamVolumeFormat to
,gdouble val
);
Parameters
from |
GstStreamVolumeFormat to convert from |
|
to |
GstStreamVolumeFormat to convert to |
|
val |
Volume in |
Types and Values
enum GstStreamVolumeFormat
Different representations of a stream volume. gst_stream_volume_convert_volume()
allows to convert between the different representations.
Formulas to convert from a linear to a cubic or dB volume are cbrt(val) and 20 * log10 (val).