@@ -398,14 +398,17 @@ to work.</entry>
<row id="v4l2-alpha-component">
<entry><constant>V4L2_CID_ALPHA_COMPONENT</constant></entry>
<entry>integer</entry>
- <entry> Sets the alpha color component on the capture device or on
- the capture buffer queue of a mem-to-mem device. When a mem-to-mem
- device produces frame format that includes an alpha component
+ <entry>Sets the alpha color component. When a capture device (or
+ capture queue of a mem-to-mem device) produces a frame format that
+ includes an alpha component
(e.g. <link linkend="rgb-formats">packed RGB image formats</link>)
- and the alpha value is not defined by the mem-to-mem input data
- this control lets you select the alpha component value of all
- pixels. It is applicable to any pixel format that contains an alpha
- component.
+ and the alpha value is not defined by the device or the mem-to-mem
+ input data this control lets you select the alpha component value of
+ all pixels. When an output device (or output queue of a mem-to-mem
+ device) consumes a frame format that doesn't include an alpha
+ component and the device supports alpha channel processing this
+ control lets you set the alpha component value of all pixels for
+ further processing in the device.
</entry>
</row>
<row>
Extend the V4L2_CID_ALPHA_COMPONENT control for use on output devices, to set the alpha component value when the output format doesn't have an alpha channel. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> --- Documentation/DocBook/media/v4l/controls.xml | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-)