Hi Sylwester and Hans,
On Thursday 24 November 2011 12:00:45 Hans Verkuil wrote:
> On Thursday, November 24, 2011 11:53:16 Sylwester Nawrocki wrote:
> > This control is intended for video capture or memory-to-memory
> > devices that are capable of setting up the alpha conponent to
> > some arbitrary value.
> > The V4L2_CID_COLOR_ALPHA control allows to set the alpha channel
> > globally to a value in range from 0 to 255.
> >
> > Signed-off-by: Sylwester Nawrocki <[email protected]>
> > Signed-off-by: Kyungmin Park <[email protected]>
> > ---
> >
> > Documentation/DocBook/media/v4l/controls.xml | 20
> > ++++++++++++++------ .../DocBook/media/v4l/pixfmt-packed-rgb.xml
> > | 7 +++++-- drivers/media/video/v4l2-ctrls.c |
> > 7 +++++++ include/linux/videodev2.h | 6
> > +++--- 4 files changed, 29 insertions(+), 11 deletions(-)
> >
> > diff --git a/Documentation/DocBook/media/v4l/controls.xml
> > b/Documentation/DocBook/media/v4l/controls.xml index 3bc5ee8..7f99222
> > 100644
> > --- a/Documentation/DocBook/media/v4l/controls.xml
> > +++ b/Documentation/DocBook/media/v4l/controls.xml
> > @@ -324,12 +324,6 @@ minimum value disables backlight
> > compensation.</entry>
> >
> > (usually a microscope).</entry>
> >
> > </row>
> > <row>
> >
> > - <entry><constant>V4L2_CID_LASTP1</constant></entry>
> > - <entry></entry>
> > - <entry>End of the predefined control IDs (currently
> > -<constant>V4L2_CID_ILLUMINATORS_2</constant> + 1).</entry>
> > - </row>
> > - <row>
> >
> > <entry><constant>V4L2_CID_MIN_BUFFERS_FOR_CAPTURE</constant></entry
> > > <entry>integer</entry>
> > <entry>This is a read-only control that can be read by the
> > application
> >
> > @@ -345,6 +339,20 @@ and used as a hint to determine the number of OUTPUT
> > buffers to pass to REQBUFS.
> >
> > The value is the minimum number of OUTPUT buffers that is necessary for
> > hardware to work.</entry>
> >
> > </row>
> >
> > + <row id="v4l2-color-alpha">
> > + <entry><constant>V4L2_CID_COLOR_ALPHA</constant></entry>
> > + <entry>integer</entry>
> > + <entry> Sets the color alpha component on the capture device. It is
> > + applicable to any pixel formats that contain the alpha component,
> > + e.g. <link linkend="rgb-formats">packed RGB image formats</link>.
> > + </entry>
As the alpha value is global, isn't it applicable to formats with no alpha
component as well ?
> > + </row>
> > + <row>
> > + <entry><constant>V4L2_CID_LASTP1</constant></entry>
> > + <entry></entry>
> > + <entry>End of the predefined control IDs (currently
> > + <constant>V4L2_CID_COLOR_ALPHA</constant> + 1).</entry>
> > + </row>
> >
> > <row>
> >
> > <entry><constant>V4L2_CID_PRIVATE_BASE</constant></entry>
> > <entry></entry>
> >
> > diff --git a/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml
> > b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml index
> > 4db272b..da4c360 100644
> > --- a/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml
> > +++ b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml
> > @@ -428,8 +428,11 @@ colorspace
> > <constant>V4L2_COLORSPACE_SRGB</constant>.</para>
> >
> > <para>Bit 7 is the most significant bit. The value of a = alpha
> >
> > bits is undefined when reading from the driver, ignored when writing
> > to the driver, except when alpha blending has been negotiated for a
> >
> > -<link linkend="overlay">Video Overlay</link> or <link
> > -linkend="osd">Video Output Overlay</link>.</para>
> > +<link linkend="overlay">Video Overlay</link> or <link linkend="osd">
> > +Video Output Overlay</link> or when global alpha has been configured
> > +for a <link linkend="capture">Video Capture</link> by means of
> > +<link linkend="v4l2-color-alpha"> <constant>V4L2_CID_COLOR_ALPHA
> > +</constant> </link> control.</para>
> >
> > <example>
> >
> > <title><constant>V4L2_PIX_FMT_BGR24</constant> 4 × 4 pixel
> >
> > diff --git a/drivers/media/video/v4l2-ctrls.c
> > b/drivers/media/video/v4l2-ctrls.c index 5552f81..bd90955 100644
> > --- a/drivers/media/video/v4l2-ctrls.c
> > +++ b/drivers/media/video/v4l2-ctrls.c
> > @@ -466,6 +466,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> >
> > case V4L2_CID_ILLUMINATORS_2: return "Illuminator 2";
> > case V4L2_CID_MIN_BUFFERS_FOR_CAPTURE: return "Minimum Number of
> > Capture Buffers"; case V4L2_CID_MIN_BUFFERS_FOR_OUTPUT: return
> > "Minimum Number of Output Buffers";
> >
> > + case V4L2_CID_COLOR_ALPHA: return "Color Alpha";
>
> I prefer CID_ALPHA_COLOR and string "Alpha Color". I think it is more
> natural than the other way around.
I'm not too found of "color" in the name. Is the alpha value considered as a
color ?
> Other than that I'm OK with this.
>
> Regards,
>
> Hans
>
> > /* MPEG controls */
> > /* Keep the order of the 'case's the same as in videodev2.h! */
> >
> > @@ -714,6 +715,12 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum
> > v4l2_ctrl_type *type,
> >
> > /* Max is calculated as RGB888 that is 2^24 */
> > *max = 0xFFFFFF;
> > break;
> >
> > + case V4L2_CID_COLOR_ALPHA:
> > + *type = V4L2_CTRL_TYPE_INTEGER;
> > + *step = 1;
> > + *min = 0;
> > + *max = 0xff;
> > + break;
> >
> > case V4L2_CID_FLASH_FAULT:
> > *type = V4L2_CTRL_TYPE_BITMASK;
> > break;
> >
> > diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> > index 4b752d5..42192c1 100644
> > --- a/include/linux/videodev2.h
> > +++ b/include/linux/videodev2.h
> > @@ -1204,10 +1204,10 @@ enum v4l2_colorfx {
> >
> > #define V4L2_CID_MIN_BUFFERS_FOR_CAPTURE (V4L2_CID_BASE+39)
> > #define V4L2_CID_MIN_BUFFERS_FOR_OUTPUT (V4L2_CID_BASE+40)
> >
> > -/* last CID + 1 */
> > -#define V4L2_CID_LASTP1 (V4L2_CID_BASE+41)
> > +#define V4L2_CID_COLOR_ALPHA (V4L2_CID_BASE+41)
> >
> > -/* Minimum number of buffer neede by the device */
> > +/* last CID + 1 */
> > +#define V4L2_CID_LASTP1 (V4L2_CID_BASE+42)
> >
> > /* MPEG-class control IDs defined by V4L2 */
> > #define V4L2_CID_MPEG_BASE (V4L2_CTRL_CLASS_MPEG |
> > 0x900)
--
Regards,
Laurent Pinchart
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