From: Lad, Prabhakar <prabhakar.lad@xxxxxx> 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 <prabhakar.lad@xxxxxx> Signed-off-by: Manjunath Hadli <manjunath.hadli@xxxxxx> Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> Reviewed-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx> Cc: Sakari Ailus <sakari.ailus@xxxxxx> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx> Cc: Hans de Goede <hdegoede@xxxxxxxxxx> Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> Cc: Rob Landley <rob@xxxxxxxxxxx> --- This patches has one checkpatch warning for line over 80 characters altough it can be avoided I have kept it for consistency. Changes for v5: 1: Changed the control's name to 'Simple' and 'Advanced' as pointed by Sakari. 2: Changed the description of DPCM. Thanks to Sakari for providing the description. Changes for v4: 1: Aligned the description to fit appropriately in the para tag, pointed by Sylwester. Changes for v3: 1: Added better explanation for DPCM, pointed by Hans. 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 | 39 +++++++++++++++++++++++++- drivers/media/v4l2-core/v4l2-ctrls.c | 9 ++++++ include/linux/videodev2.h | 5 +++ 3 files changed, 52 insertions(+), 1 deletions(-) diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index 93b9c68..2c1599f 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -4267,7 +4267,44 @@ 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"> Differential pulse-code modulation (DPCM) compression can + be used to compress the samples into fewer bits than they would otherwise require. + This is done by calculating the difference between consecutive samples and outputting + the difference which in average is much smaller than the values of the samples + themselves since there is generally lots of correlation between adjacent pixels. In + decompression the original samples are reconstructed. The process isn't lossless as + the encoded sample size in bits is less than the original. + + <para>Formats using DPCM compression include <xref linkend="pixfmt-srggb10dpcm8" />.</para> + + <para>This control is used to select the predictor used to encode the samples.</para> + + <para>The main difference between the simple and the advanced predictors is image quality, + with advanced predictor supposed to produce better quality images as a result. Simple + predictor can be used e.g. for testing purposes. For more information about DPCM see <ulink + url="http://en.wikipedia.org/wiki/Differential_pulse-code_modulation";>Wikipedia</ulink>.</para> + </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..8f2f40b 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", + "Advanced", + 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 -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
