Hi Laurent,
On 09/27/2012 01:10 PM, Laurent Pinchart wrote:
> 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@xxxxxxxxxxx>
>> Signed-off-by: Kyungmin Park<kyungmin.park@xxxxxxxxxxx>
>> ---
>> 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." ?
Ah, right. Thank you for catching it.
> Can it still be useful for some applications, or is it complete garbage ?
I don't really know... I don't have good documentation for this. It is
very likely there is some more interesting data in this 4 kiB buffer.
So by "undefined" I meant "has undefined meaning" or "I don't know what's
there at the moment"... From the requirements, it's only needed to decode
the interleaved data and very likely won't be needed for anything else.
Perhaps I should change this sentence to
"Remaining data in the first plane has undefined meaning." or drop it
entirely ?
>> 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,
Sylwester
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