smptealpha

smptealpha — Takes a video frames and applies an SMPTE transition effect on it in the alpha channel.

Synopsis

                    GstSMPTEAlpha;

Object Hierarchy

  GObject
   +----GstObject
         +----GstElement
               +----GstBaseTransform
                     +----GstVideoFilter
                           +----GstSMPTEAlpha

Properties

  "border"                   gint                  : Read / Write
  "depth"                    gint                  : Read / Write
  "position"                 gdouble               : Read / Write
  "type"                     GstSMPTEAlphaTransitionType  : Read / Write

Description

Sample pipelines

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 "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 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.

Here is a pipeline to demonstrate the smpte transition :

gst-launch -v videotestsrc ! smptealpha border=20000 type=44
position=0.5 ! videomixer ! ffmpegcolorspace ! 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.

Synopsis

Element Information

plugin

smpte

author

Wim Taymans <wim.taymans@gmail.com>

class

Filter/Editor/Video

Element Pads

name

src

direction

source

presence

always

details

video/x-raw-yuv, format=(fourcc)AYUV, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

name

sink

direction

sink

presence

always

details

video/x-raw-yuv, format=(fourcc)I420, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

video/x-raw-yuv, format=(fourcc)AYUV, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

Details

GstSMPTEAlpha

typedef struct _GstSMPTEAlpha GstSMPTEAlpha;

Property Details

The "border" property

  "border"                   gint                  : Read / Write

The border width of the transition.

Allowed values: >= 0

Default value: 0


The "depth" property

  "depth"                    gint                  : Read / Write

Depth of the mask in bits.

Allowed values: [1,24]

Default value: 16


The "position" property

  "position"                 gdouble               : Read / Write

Position of the transition effect.

Allowed values: [0,1]

Default value: 0


The "type" property

  "type"                     GstSMPTEAlphaTransitionType  : Read / Write

The type of transition to use.

Default value: A bar moves from left to right