Re: Support for RGB/YUV 10, 12 BPC(bits per color/component) image data formats in kernel

[Ajay kumar]

Hi Sakari,

On Sat, Jun 3, 2017 at 1:48 PM, Sakari Ailus <sakari.ailus@xxxxxx> wrote:
> Hi Ajay,
>
> On Fri, Jun 02, 2017 at 06:38:53PM +0530, Ajay kumar wrote:
>> Hi all,
>>
>> I have tried searching for RGB/YUV 10, 12 BPC formats in videodev2.h,
>> media-bus-format.h and drm_fourcc.h
>> I could only find RGB 10BPC support in drm_fourcc.h.
>> I guess not much support is present for formats with (BPC > 8) in the kernel.
>
> What's "BPC"? Most YUV and RGB formats have only 8 bits per sample. More
> format definitions may be added if there's a driver that makes use of them.
BPC : Bits Per Color/Component
In my project, we have an image capture device which can capture 10 or
12 bits for each of R, G, B colors, i.e:
R[0:9] G[0:9] B[0:9] and
R[0:11] G[0:11] B[0:11]

I want to define macros for the above formats in videodev2.h.
But, I am not getting the logic behind the naming convention used to
define v4l2_fourcc macros.
ex:
V4L2_PIX_FMT_ARGB32      v4l2_fourcc('A', 'R', '2', '4');

How did they choose the characters 'A', 'R', '2', '4' in the above case?

I want to know the logic/naming convention behind that, so that I can create
new v4l2_fourcc defines for 10, 12 BPC formats and use in my driver.

Thanks,
Ajay Kumar
>>
>> Are there any plans to add fourcc defines for such formats?
>> Also, I wanted to how to define fourcc code for those formats?
>
> --
> Regards,
>
> Sakari Ailus
> e-mail: sakari.ailus@xxxxxx     XMPP: sailus@xxxxxxxxxxxxxx