# smptealpha

smptealpha can accept an I420 or AYUV video stream. An alpha channel is added using an effect specific SMPTE mask in the I420 input case. In the AYUV case, the alpha channel is modified using the effect specific SMPTE mask.

The GstSMPTEAlpha:position property is a controllabe double between 0.0 and 1.0 that specifies the position in the transition. 0.0 is the start of the transition with the alpha channel to complete opaque where 1.0 has the alpha channel set to completely transparent.

The GstSMPTEAlpha:depth property defines the precision in bits of the mask. A higher presision will create a mask with smoother gradients in order to avoid banding.

## Sample pipelines

Here is a pipeline to demonstrate the smpte transition :

     gst-launch-1.0 -v videotestsrc ! smptealpha border=20000 type=44
     position=0.5 ! videomixer ! videoconvert ! ximagesink

This shows a midway bowtie-h transition a from a videotestsrc to a transparent image. The edges of the transition are smoothed with a 20000 big border.

## Hierarchy

    GObject
        ╰──GInitiallyUnowned
            ╰──GstObject
                ╰──GstElement
                    ╰──GstBaseTransform
                        ╰──GstVideoFilter
                            ╰──smptealpha

## Factory details

Authors: – Wim Taymans

Classification: – `Filter/Editor/Video`

Rank – none

Plugin – smpte

Package – GStreamer Good Plug-ins

## Pad Templates

### `sink`

    video/x-raw:
             format: I420
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: YV12
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: AYUV
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: ARGB
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: BGRA
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: RGBA
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: ARGB
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]

Presence – always

Direction – sink

Object type – GstPad

### `src`

    video/x-raw:
             format: AYUV
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: ARGB
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: BGRA
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: RGBA
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
    video/x-raw:
             format: ARGB
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]

Presence – always

Direction – src

Object type – GstPad

## Properties

### border

    “border” gint

The border width of the transition

Flags : Read / Write

Default value : 0

### depth

    “depth” gint

Depth of the mask in bits

Flags : Read / Write

Default value : 16

### invert

    “invert” gboolean

Set to TRUE to invert the transition mask (ie. flip it horizontally).

Flags : Read / Write

Default value : false

### position

    “position” gdouble

Position of the transition effect

Flags : Read / Write

Default value : 0

### type

    “type” Smptealpha-transition-type *

The type of transition to use

Flags : Read / Write

Default value : bar-wipe-lr (1)

## Named constants

### Smptealpha-transition-type

#### Members

`bar-wipe-lr` (1) – A bar moves from left to right
`bar-wipe-tb` (2) – A bar moves from top to bottom
`box-wipe-tl` (3) – A box expands from the upper-left corner to the lower-right corner
`box-wipe-tr` (4) – A box expands from the upper-right corner to the lower-left corner
`box-wipe-br` (5) – A box expands from the lower-right corner to the upper-left corner
`box-wipe-bl` (6) – A box expands from the lower-left corner to the upper-right corner
`four-box-wipe-ci` (7) – A box shape expands from each of the four corners toward the center
`four-box-wipe-co` (8) – A box shape expands from the center of each quadrant toward the corners of each quadrant
`barndoor-v` (21) – A central, vertical line splits and expands toward the left and right edges
`barndoor-h` (22) – A central, horizontal line splits and expands toward the top and bottom edges
`box-wipe-tc` (23) – A box expands from the top edge's midpoint to the bottom corners
`box-wipe-rc` (24) – A box expands from the right edge's midpoint to the left corners
`box-wipe-bc` (25) – A box expands from the bottom edge's midpoint to the top corners
`box-wipe-lc` (26) – A box expands from the left edge's midpoint to the right corners
`diagonal-tl` (41) – A diagonal line moves from the upper-left corner to the lower-right corner
`diagonal-tr` (42) – A diagonal line moves from the upper right corner to the lower-left corner
`bowtie-v` (43) – Two wedge shapes slide in from the top and bottom edges toward the center
`bowtie-h` (44) – Two wedge shapes slide in from the left and right edges toward the center
`barndoor-dbl` (45) – A diagonal line from the lower-left to upper-right corners splits and expands toward the opposite corners
`barndoor-dtl` (46) – A diagonal line from upper-left to lower-right corners splits and expands toward the opposite corners
`misc-diagonal-dbd` (47) – Four wedge shapes split from the center and retract toward the four edges
`misc-diagonal-dd` (48) – A diamond connecting the four edge midpoints simultaneously contracts toward the center and expands toward the edges
`vee-d` (61) – A wedge shape moves from top to bottom
`vee-l` (62) – A wedge shape moves from right to left
`vee-u` (63) – A wedge shape moves from bottom to top
`vee-r` (64) – A wedge shape moves from left to right
`barnvee-d` (65) – A 'V' shape extending from the bottom edge's midpoint to the opposite corners contracts toward the center and expands toward the edges
`barnvee-l` (66) – A 'V' shape extending from the left edge's midpoint to the opposite corners contracts toward the center and expands toward the edges
`barnvee-u` (67) – A 'V' shape extending from the top edge's midpoint to the opposite corners contracts toward the center and expands toward the edges
`barnvee-r` (68) – A 'V' shape extending from the right edge's midpoint to the opposite corners contracts toward the center and expands toward the edges
`iris-rect` (101) – A rectangle expands from the center.
`clock-cw12` (201) – A radial hand sweeps clockwise from the twelve o'clock position
`clock-cw3` (202) – A radial hand sweeps clockwise from the three o'clock position
`clock-cw6` (203) – A radial hand sweeps clockwise from the six o'clock position
`clock-cw9` (204) – A radial hand sweeps clockwise from the nine o'clock position
`pinwheel-tbv` (205) – Two radial hands sweep clockwise from the twelve and six o'clock positions
`pinwheel-tbh` (206) – Two radial hands sweep clockwise from the nine and three o'clock positions
`pinwheel-fb` (207) – Four radial hands sweep clockwise
`fan-ct` (211) – A fan unfolds from the top edge, the fan axis at the center
`fan-cr` (212) – A fan unfolds from the right edge, the fan axis at the center
`doublefan-fov` (213) – Two fans, their axes at the center, unfold from the top and bottom
`doublefan-foh` (214) – Two fans, their axes at the center, unfold from the left and right
`singlesweep-cwt` (221) – A radial hand sweeps clockwise from the top edge's midpoint
`singlesweep-cwr` (222) – A radial hand sweeps clockwise from the right edge's midpoint
`singlesweep-cwb` (223) – A radial hand sweeps clockwise from the bottom edge's midpoint
`singlesweep-cwl` (224) – A radial hand sweeps clockwise from the left edge's midpoint
`doublesweep-pv` (225) – Two radial hands sweep clockwise and counter-clockwise from the top and bottom edges' midpoints
`doublesweep-pd` (226) – Two radial hands sweep clockwise and counter-clockwise from the left and right edges' midpoints
`doublesweep-ov` (227) – Two radial hands attached at the top and bottom edges' midpoints sweep from right to left
`doublesweep-oh` (228) – Two radial hands attached at the left and right edges' midpoints sweep from top to bottom
`fan-t` (231) – A fan unfolds from the bottom, the fan axis at the top edge's midpoint
`fan-r` (232) – A fan unfolds from the left, the fan axis at the right edge's midpoint
`fan-b` (233) – A fan unfolds from the top, the fan axis at the bottom edge's midpoint
`fan-l` (234) – A fan unfolds from the right, the fan axis at the left edge's midpoint
`doublefan-fiv` (235) – Two fans, their axes at the top and bottom, unfold from the center
`doublefan-fih` (236) – Two fans, their axes at the left and right, unfold from the center
`singlesweep-cwtl` (241) – A radial hand sweeps clockwise from the upper-left corner
`singlesweep-cwbl` (242) – A radial hand sweeps counter-clockwise from the lower-left corner.
`singlesweep-cwbr` (243) – A radial hand sweeps clockwise from the lower-right corner
`singlesweep-cwtr` (244) – A radial hand sweeps counter-clockwise from the upper-right corner
`doublesweep-pdtl` (245) – Two radial hands attached at the upper-left and lower-right corners sweep down and up
`doublesweep-pdbl` (246) – Two radial hands attached at the lower-left and upper-right corners sweep down and up
`saloondoor-t` (251) – Two radial hands attached at the upper-left and upper-right corners sweep down
`saloondoor-l` (252) – Two radial hands attached at the upper-left and lower-left corners sweep to the right
`saloondoor-b` (253) – Two radial hands attached at the lower-left and lower-right corners sweep up
`saloondoor-r` (254) – Two radial hands attached at the upper-right and lower-right corners sweep to the left
`windshield-r` (261) – Two radial hands attached at the midpoints of the top and bottom halves sweep from right to left
`windshield-u` (262) – Two radial hands attached at the midpoints of the left and right halves sweep from top to bottom
`windshield-v` (263) – Two sets of radial hands attached at the midpoints of the top and bottom halves sweep from top to bottom and bottom to top
`windshield-h` (264) – Two sets of radial hands attached at the midpoints of the left and right halves sweep from left to right and right to left

The results of the search are