| Top |  |  |  |  | 
| gdouble | alpha | Read / Write | 
| gfloat | angle | Read / Write | 
| GstAlphaMethod | method | Read / Write | 
| gfloat | noise-level | Read / Write | 
| guint | target-b | Read / Write | 
| guint | target-g | Read / Write | 
| guint | target-r | Read / Write | 
| guint | black-sensitivity | Read / Write | 
| guint | white-sensitivity | Read / Write | 
| gboolean | prefer-passthrough | Read / Write | 
    GObject
    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstElement
                ╰── GstBaseTransform
                    ╰── GstVideoFilter
                        ╰── GstAlpha
The alpha element adds an alpha channel to a video stream. The values of the alpha channel can be either be set to a constant or can be dynamically calculated via chroma keying, e.g. blue can be set as the transparent color.
Sample pipeline:
| 1 2 3 4 | gst-launch-1.0 videotestsrc pattern=snow ! mixer.sink_0 \ videotestsrc pattern=smpte75 ! alpha method=green ! mixer.sink_1 \ videomixer name=mixer sink_0::zorder=0 sink_1::zorder=1 ! \ videoconvert ! autovideosink | 
This pipeline adds a alpha channel to the SMPTE color bars with green as the transparent color and overlays the output on top of a snow video stream.
| plugin | alpha | 
| author | Wim Taymans <wim.taymans@gmail.com> Edward Hervey <edward.hervey@collabora.co.uk> Jan Schmidt <thaytan@noraisin.net> | 
| class | Filter/Effect/Video | 
| name | sink | 
| direction | sink | 
| presence | always | 
| details | video/x-raw, format=(string){ AYUV, ARGB, BGRA, ABGR, RGBA, Y444, xRGB, BGRx, xBGR, RGBx, RGB, BGR, Y42B, YUY2, YVYU, UYVY, I420, YV12, Y41B }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ] | 
| name | src | 
| direction | source | 
| presence | always | 
| details | video/x-raw, format=(string){ AYUV, ARGB, BGRA, ABGR, RGBA, Y444, xRGB, BGRx, xBGR, RGBx, RGB, BGR, Y42B, YUY2, YVYU, UYVY, I420, YV12, Y41B }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ] | 
“alpha” property  “alpha”                    gdouble
The value for the alpha channel.
Flags: Read / Write
Allowed values: [0,1]
Default value: 1
“angle” property  “angle”                    gfloat
Size of the colorcube to change.
Flags: Read / Write
Allowed values: [0,90]
Default value: 20
“method” property“method” GstAlphaMethod
How the alpha channels should be created.
Flags: Read / Write
Default value: Set/adjust alpha channel
“noise-level” property  “noise-level”              gfloat
Size of noise radius.
Flags: Read / Write
Allowed values: [0,64]
Default value: 2
“target-b” property  “target-b”                 guint
The blue color value for custom RGB chroma keying.
Flags: Read / Write
Allowed values: <= 255
Default value: 0
“target-g” property  “target-g”                 guint
The green color value for custom RGB chroma keying.
Flags: Read / Write
Allowed values: <= 255
Default value: 255
“target-r” property  “target-r”                 guint
The red color value for custom RGB chroma keying.
Flags: Read / Write
Allowed values: <= 255
Default value: 0
“black-sensitivity” property  “black-sensitivity”        guint
Sensitivity to dark colors.
Flags: Read / Write
Allowed values: <= 128
Default value: 100
“white-sensitivity” property  “white-sensitivity”        guint
Sensitivity to bright colors.
Flags: Read / Write
Allowed values: <= 128
Default value: 100