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Re: [PATCH v2 2/6] [media] Documentation: Add HSV format

From Hans Verkuil <hverkuil@xs4all.nl>
Newsgroups linux.kernel
Subject Re: [PATCH v2 2/6] [media] Documentation: Add HSV format
Date 2016-07-16 16:00 +0200
Message-ID <rVyil-4uf-7@gated-at.bofh.it> (permalink)
References <rVe0h-D2-3@gated-at.bofh.it> <rVfSp-1LH-11@gated-at.bofh.it> <rVsZk-1nq-9@gated-at.bofh.it> <rVx2V-3O4-9@gated-at.bofh.it>
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On 07/16/2016 02:38 PM, Laurent Pinchart wrote:
> Hi Hans,
> 
> On Saturday 16 Jul 2016 10:19:29 Hans Verkuil wrote:
>> On 07/15/2016 08:11 PM, Laurent Pinchart wrote:
>>> On Friday 15 Jul 2016 18:13:15 Ricardo Ribalda Delgado wrote:
>>>> Describe the HSV formats
>>>>
>>>> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
>>>> ---
>>>>
>>>>  Documentation/media/uapi/v4l/hsv-formats.rst       |  19 ++
>>>>  Documentation/media/uapi/v4l/pixfmt-packed-hsv.rst | 253 +++++++++++++++
>>>>  Documentation/media/uapi/v4l/pixfmt.rst            |   1 +
>>>>  Documentation/media/uapi/v4l/v4l2.rst              |   5 +
>>>>  4 files changed, 278 insertions(+)
>>>>  create mode 100644 Documentation/media/uapi/v4l/hsv-formats.rst
>>>>  create mode 100644 Documentation/media/uapi/v4l/pixfmt-packed-hsv.rst
>>>>
>>>> diff --git a/Documentation/media/uapi/v4l/hsv-formats.rst
>>>> b/Documentation/media/uapi/v4l/hsv-formats.rst new file mode 100644
>>>> index 000000000000..f0f2615eaa95
>>>> --- /dev/null
>>>> +++ b/Documentation/media/uapi/v4l/hsv-formats.rst
>>>> @@ -0,0 +1,19 @@
>>>> +.. -*- coding: utf-8; mode: rst -*-
>>>> +
>>>> +.. _hsv-formats:
>>>> +
>>>> +***********
>>>> +HSV Formats
>>>> +***********
>>>> +
>>>> +These formats store the color information of the image
>>>> +in a geometrical representation. The colors are mapped into a
>>>> +cylinder, where the angle is the HUE, the height is the VALUE
>>>> +and the distance to the center is the SATURATION. This is a very
>>>> +useful format for image segmentation algorithms.
>>>> +
>>>> +
>>>> +.. toctree::
>>>> +    :maxdepth: 1
>>>> +
>>>> +    pixfmt-packed-hsv
>>>> diff --git a/Documentation/media/uapi/v4l/pixfmt-packed-hsv.rst
>>>> b/Documentation/media/uapi/v4l/pixfmt-packed-hsv.rst new file mode 100644
>>>> index 000000000000..b297aa4f7ba6
>>>> --- /dev/null
>>>> +++ b/Documentation/media/uapi/v4l/pixfmt-packed-hsv.rst
>>>> @@ -0,0 +1,253 @@
>>>> +.. -*- coding: utf-8; mode: rst -*-
>>>> +
>>>> +.. _packed-hsv:
>>>> +
>>>> +******************
>>>> +Packed HSV formats
>>>> +******************
>>>> +
>>>> +*man Packed HSV formats(2)*
>>>> +
>>>> +Packed HSV formats
>>>> +
>>>> +
>>>> +Description
>>>> +===========
>>>> +
>>>> +The HUE (h) is meassured in degrees, one LSB represents two degrees.
>>>
>>> Is this common ? I have a device that can handle HSV data, I need to check
>>> how it maps the hue values to binary, but I'm pretty sure they cover the
>>> full 0-255 range. We would then have to support the two formats. Separate
>>> 4CCs are an option, but reporting the range separately (possibly through
>>> the colorspace API) might be better. Any thought on that ?
>>
>> It's either a separate 4cc or we do something with the ycbcr_enc field
>> (reinterpreted as hsv_enc). I'm not sure, I would have to think some more
>> about that.
> 
> I'm inclined to use the ycbcr_enc field, especially given that a similar usage 
> could be useful for RGB as well (don't ask me what it's supposed to be used 
> for, but I have hardware that support limiting the RGB values range to 
> 16-235).

Limited vs full range quantization is handled by the quantization field. It's
there already.

Limited range RGB is needed for HDMI due to a brain-dead spec when dealing with
certain kinds of TVs and configurations. Don't ask, it's horrible.

Anyway, I am inclined to use ycbcr_enc as well.

Regards,

	Hans

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Thread

[PATCH v2 0/6] Add HSV format Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-15 18:20 +0200
  [PATCH v2 3/6] [media] Documentation: Add Ricardo Ribalda Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-15 18:20 +0200
  [PATCH v2 2/6] [media] Documentation: Add HSV format Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-15 18:20 +0200
    Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-07-15 20:20 +0200
      Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-16 10:20 +0200
        Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-07-16 14:40 +0200
          Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-16 16:00 +0200
            Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-07-16 16:20 +0200
              Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-16 16:40 +0200
                Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-16 17:30 +0200
                Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-16 18:00 +0200
                Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-16 18:20 +0200
              Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-16 17:20 +0200
      Re: [PATCH v2 2/6] [media] Documentation: Add HSV format Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-16 10:30 +0200
  [PATCH v2 6/6] [media] vivid: Rename variable Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-15 18:20 +0200
  [PATCH v2 5/6] [media] vivid: Add support for HSV formats Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-15 18:20 +0200
    Re: [PATCH v2 5/6] [media] vivid: Add support for HSV formats Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-15 20:30 +0200
  [PATCH v2 4/6] [media] vivid: code refactor for color representation Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> - 2016-07-15 18:20 +0200
    Re: [PATCH v2 4/6] [media] vivid: code refactor for color  representation Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-15 20:00 +0200
      Re: [PATCH v2 4/6] [media] vivid: code refactor for color  representation Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-15 20:20 +0200
    Re: [PATCH v2 4/6] [media] vivid: code refactor for color  representation Hans Verkuil <hverkuil@xs4all.nl> - 2016-07-15 20:30 +0200

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