Re: [PATCH RFC v3 2/5] V4L: Add V4L2_PIX_FMT_S5C_UYVY_JPG fourcc definition

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sylwester,

Thank you for the patch.

On Wednesday 26 September 2012 17:54:10 Sylwester Nawrocki wrote:
> This patch adds definition of the Samsung S5C73M3 camera specific
> image format. V4L2_PIX_FMT_S5C_UYVY_JPG is a two-planar format,
> the  first plane contains interleaved UYVY and JPEG data followed
> by meta-data. The second plane contains additional meta-data needed
> for extracting JPEG and UYVY data stream from the first plane.
> 
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  Documentation/DocBook/media/v4l/pixfmt.xml | 28 +++++++++++++++++++++++++++
>  include/linux/videodev2.h                  |  1 +
>  2 files changed, 29 insertions(+)
> 
> diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml
> b/Documentation/DocBook/media/v4l/pixfmt.xml index 1ddbfab..21284ba 100644
> --- a/Documentation/DocBook/media/v4l/pixfmt.xml
> +++ b/Documentation/DocBook/media/v4l/pixfmt.xml
> @@ -996,6 +996,34 @@ the other bits are set to 0.</entry>
>  	    <entry>Old 6-bit greyscale format. Only the most significant 6 bits 
of
> each byte are used, the other bits are set to 0.</entry>
>  	  </row>
> +	  <row id="V4L2-PIX-FMT-S5C-UYVY-JPG">
> +	    <entry><constant>V4L2_PIX_FMT_S5C_UYVY_JPG</constant></entry>
> +	    <entry>'S5CI'</entry>
> +	    <entry>Two-planar format used by Samsung S5C73MX cameras. The
> +first plane contains interleaved JPEG and UYVY image data, followed by meta
> data in form of an array of offsets to the UYVY data blocks. The actual
> pointer array follows immediately the interleaved JPEG/UYVY data, the number
> of entries in this array equals the height of the UYVY image. Each entry is
> a 4-byte unsigned integer in big endian order and it's an offset to a single
> pixel line of the UYVY image. The first plane can start either with JPEG or
> UYVY data chunk. The size of a single UYVY block equals the UYVY image's
> width multiplied by 2. The size of a JPEG chunk depends on the image and can
> vary with each line.
> +<para>The second plane, at an offset of 4084 bytes, contains a 4-byte
> offset to the pointer array in the first plane. This offset is followed by a
> 4-byte value indicating size of the pointer array. All numbers in the second
> plane are also in big endian order. Remaining data in the first plane is
> undefined.

Do you mean "remaining data in the second plane is undefined." ?

Can it still be useful for some applications, or is it complete garbage ?

> The information in the second plane allows to easily find location of the
> pointer array, which can be different for each frame. The size of the
> pointer array is +constant for given UYVY image height.</para>
> +<para>In order to extract UYVY and JPEG frames an application can initially
> set a data pointer to the start of first plane and then add an offset from
> the first entry of the pointers table. Such a pointer indicates start of an
> UYVY image pixel line. Whole UYVY line can be copied to a separate buffer.
> These steps should be repeated for each line, i.e. the number of entries in
> the pointer array. Anything what's in between the UYVY lines is JPEG data
> and should be concatenated to form the JPEG stream. </para>
> +</entry>
> +	  </row>
>  	</tbody>
>        </tgroup>
>      </table>
> diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> index 8d29bb2..6c82ff5 100644
> --- a/include/linux/videodev2.h
> +++ b/include/linux/videodev2.h
> @@ -436,6 +436,7 @@ struct v4l2_pix_format {
>  #define V4L2_PIX_FMT_KONICA420  v4l2_fourcc('K', 'O', 'N', 'I') /* YUV420
> planar in blocks of 256 pixels */ #define
> V4L2_PIX_FMT_JPGL	v4l2_fourcc('J', 'P', 'G', 'L') /* JPEG-Lite */ #define
> V4L2_PIX_FMT_SE401      v4l2_fourcc('S', '4', '0', '1') /* se401 janggu
> compressed rgb */ +#define V4L2_PIX_FMT_S5C_UYVY_JPG v4l2_fourcc('S', '5',
> 'C', 'J') /* S5C73M3 interleaved UYVY/JPEG */
> 
>  /*
>   *	F O R M A T   E N U M E R A T I O N
-- 
Regards,

Laurent Pinchart