# glalphacombine

Combines two RGBA OpenGL textures by taking RGB from the color input and alpha from a configurable component of the alpha input.

This is useful for GL decoder or import paths where color and alpha streams are both exposed as sampled RGBA textures. For example, Android decoders and EGLImage-based embedded Linux paths may expose frames as external-oes textures, so the alpha stream has already been sampled as RGBA instead of being exposed as a separate luma plane.

The sink pads currently accept RGBA GLMemory 2D and external-oes textures and the src pad produces RGBA GLMemory 2D textures. By default, the red component of the alpha input is written to the output alpha channel.

## Hierarchy

    GObject
        ╰──GInitiallyUnowned
            ╰──GstObject
                ╰──GstElement
                    ╰──GstAggregator
                        ╰──GstVideoAggregator
                            ╰──GstGLBaseMixer
                                ╰──GstGLMixer
                                    ╰──glalphacombine

## Factory details

Authors: – GStreamer contributors

Classification: – `Filter/Editor/Video/Compositor`

Rank – none

Plugin – opengl

Package – GStreamer Base Plug-ins

## Pad Templates

### `alpha`

    video/x-raw(memory:GLMemory):
             format: RGBA
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
     texture-target: { (string)2D, (string)external-oes }

Presence – always

Direction – sink

Object type – GstGLMixerPad

### `sink`

    video/x-raw(memory:GLMemory):
             format: RGBA
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
     texture-target: { (string)2D, (string)external-oes }

Presence – always

Direction – sink

Object type – GstGLMixerPad

### `src`

    video/x-raw(memory:GLMemory):
             format: RGBA
              width: [ 1, 2147483647 ]
             height: [ 1, 2147483647 ]
          framerate: [ 0/1, 2147483647/1 ]
     texture-target: 2D

Presence – always

Direction – src

Object type – GstAggregatorPad

## Properties

### alpha-component

    “alpha-component” Glalpha-combine-alpha-component *

The RGBA component sampled from the alpha input and written to output alpha.

Flags : Read / Write

Default value : red (0)

Since : 1.30

## Named constants

### Glalpha-combine-alpha-component

The RGBA component to sample from the alpha input and write to the output alpha channel.

#### Members

`red` (0) – Red component
`green` (1) – Green component
`blue` (2) – Blue component
`alpha` (3) – Alpha component

Since : 1.30

The results of the search are