Re: [PATCH v2] media: v4l2-ctrls: add control for dpcm predictor
From: Hans Verkuil <hidden>
Date: 2012-08-30 14:59:55
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Hi Prabhakar! I've got some documentation review comments below... On Thu August 30 2012 00:58:16 Prabhakar Lad wrote:
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From: Lad, Prabhakar <redacted> add V4L2_CID_DPCM_PREDICTOR control of type menu, which determines the dpcm predictor. The predictor can be either simple or advanced. Signed-off-by: Lad, Prabhakar <redacted> Signed-off-by: Manjunath Hadli <redacted> Cc: Sakari Ailus <sakari.ailus@iki.fi> Cc: Hans Verkuil <redacted> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Mauro Carvalho Chehab <redacted> Cc: Sylwester Nawrocki <s.nawrocki@samsung.com> Cc: Hans de Goede <redacted> Cc: Kyungmin Park <kyungmin.park@samsung.com> --- This patches has one checkpatch warning for line over 80 characters altough it can be avoided I have kept it for consistency. Changes for v2: 1: Added documentaion in controls.xml pointed by Sylwester. 2: Chnaged V4L2_DPCM_PREDICTOR_ADVANCE to V4L2_DPCM_PREDICTOR_ADVANCED pointed by Sakari. Documentation/DocBook/media/v4l/controls.xml | 25 ++++++++++++++++++++++++- drivers/media/v4l2-core/v4l2-ctrls.c | 9 +++++++++ include/linux/videodev2.h | 5 +++++ 3 files changed, 38 insertions(+), 1 deletions(-)diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index 93b9c68..84746d0 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml@@ -4267,7 +4267,30 @@ interface and may change in the future.</para> pixels / second. </entry> </row> - <row><entry></entry></row> + <row> + <entry spanname="id"><constant>V4L2_CID_DPCM_PREDICTOR</constant></entry> + <entry>menu</entry> + </row> + <row id="v4l2-dpcm-predictor"> + <entry spanname="descr"> DPCM Predictor: depicts what type of prediction + is used simple or advanced.
This is not useful information. It basically just rephrases the name of the
define without actually telling me anything.
I would expect to see here at least the following:
- what the DPCM abbreviation stands for
- a link or bibliography reference to the relevant standard (if there is any)
- a high-level explanation of what this do and what the difference is between
simple and advanced.
If this is part of a video compression standard, then this control would probably
belong to the MPEG control class as well.
Regards,
Hans
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+ </entry> + </row> + <row> + <entrytbl spanname="descr" cols="2"> + <tbody valign="top"> + <row> + <entry><constant>V4L2_DPCM_PREDICTOR_SIMPLE</constant></entry> + <entry>Predictor type is simple</entry> + </row> + <row> + <entry><constant>V4L2_DPCM_PREDICTOR_ADVANCED</constant></entry> + <entry>Predictor type is advanced</entry> + </row> + </tbody> + </entrytbl> + </row> + <row><entry></entry></row> </tbody> </tgroup> </table>diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c index b6a2ee7..2d7bc15 100644 --- a/drivers/media/v4l2-core/v4l2-ctrls.c +++ b/drivers/media/v4l2-core/v4l2-ctrls.c@@ -425,6 +425,11 @@ const char * const *v4l2_ctrl_get_menu(u32 id) "Gray", NULL, }; + static const char * const dpcm_predictor[] = { + "Simple Predictor", + "Advanced Predictor", + NULL, + }; switch (id) { case V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ:@@ -502,6 +507,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id) return mpeg4_profile; case V4L2_CID_JPEG_CHROMA_SUBSAMPLING: return jpeg_chroma_subsampling; + case V4L2_CID_DPCM_PREDICTOR: + return dpcm_predictor; default: return NULL;@@ -732,6 +739,7 @@ const char *v4l2_ctrl_get_name(u32 id) case V4L2_CID_IMAGE_PROC_CLASS: return "Image Processing Controls"; case V4L2_CID_LINK_FREQ: return "Link Frequency"; case V4L2_CID_PIXEL_RATE: return "Pixel Rate"; + case V4L2_CID_DPCM_PREDICTOR: return "DPCM Predictor"; default: return NULL;@@ -832,6 +840,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type, case V4L2_CID_ISO_SENSITIVITY_AUTO: case V4L2_CID_EXPOSURE_METERING: case V4L2_CID_SCENE_MODE: + case V4L2_CID_DPCM_PREDICTOR: *type = V4L2_CTRL_TYPE_MENU; break; case V4L2_CID_LINK_FREQ:diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index 6d6dfa7..ca9fb78 100644 --- a/include/linux/videodev2.h +++ b/include/linux/videodev2.h@@ -2000,6 +2000,11 @@ enum v4l2_jpeg_chroma_subsampling { #define V4L2_CID_LINK_FREQ (V4L2_CID_IMAGE_PROC_CLASS_BASE + 1) #define V4L2_CID_PIXEL_RATE (V4L2_CID_IMAGE_PROC_CLASS_BASE + 2) +#define V4L2_CID_DPCM_PREDICTOR (V4L2_CID_IMAGE_PROC_CLASS_BASE + 3) +enum v4l2_dpcm_predictor { + V4L2_DPCM_PREDICTOR_SIMPLE = 0, + V4L2_DPCM_PREDICTOR_ADVANCED = 1, +}; /* * T U N I N G