From 6f7427f8ae2d021adfb87acaa3920c590b6740a6 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Thu, 22 May 2014 00:16:01 +0200 Subject: [PATCH] DocBook: media: Document ALPHA_COMPONENT control usage on output devices 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 (cherry picked from commit e632d2f4e25c574a29b269f9f4b0cef2995e402d) Signed-off-by: Simon Horman --- Documentation/DocBook/media/v4l/controls.xml | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index a5a3188..066800d 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -398,14 +398,17 @@ to work. V4L2_CID_ALPHA_COMPONENT integer - 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 + 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. packed RGB image formats) - 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. -- 2.7.4