From: Hans Verkuil <hverkuil@xs4all.nl>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>,
Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Antti Palosaari <crope@iki.fi>,
Guennadi Liakhovetski <guennadi.liakhovetski@intel.com>,
Helen Mae Koike Fornazier <helen.koike@collabora.co.uk>,
Philipp Zabel <p.zabel@pengutronix.de>,
Shuah Khan <shuahkh@osg.samsung.com>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/6] [media] Documentation: Add HSV format
Date: Sat, 16 Jul 2016 15:59:08 +0200 [thread overview]
Message-ID: <f0f50faf-67f6-6614-4ae3-b0f23aa09953@xs4all.nl> (raw)
In-Reply-To: <1704928.3gI88ec2Bn@avalon>
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
next prev parent reply other threads:[~2016-07-16 13:59 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-15 16:13 [PATCH v2 0/6] Add HSV format Ricardo Ribalda Delgado
2016-07-15 16:13 ` [PATCH v2 1/6] [media] videodev2.h Add HSV formats Ricardo Ribalda Delgado
2016-07-15 16:13 ` [PATCH v2 2/6] [media] Documentation: Add HSV format Ricardo Ribalda Delgado
2016-07-15 18:11 ` Laurent Pinchart
2016-07-16 8:19 ` Hans Verkuil
2016-07-16 12:38 ` Laurent Pinchart
2016-07-16 13:59 ` Hans Verkuil [this message]
2016-07-16 14:12 ` Laurent Pinchart
2016-07-16 14:32 ` Ricardo Ribalda Delgado
2016-07-16 15:28 ` Hans Verkuil
2016-07-16 15:57 ` Ricardo Ribalda Delgado
2016-07-16 16:14 ` Hans Verkuil
2016-07-16 15:19 ` Hans Verkuil
2016-07-16 8:22 ` Ricardo Ribalda Delgado
2016-07-15 16:13 ` [PATCH v2 3/6] [media] Documentation: Add Ricardo Ribalda Ricardo Ribalda Delgado
2016-07-15 16:13 ` [PATCH v2 4/6] [media] vivid: code refactor for color representation Ricardo Ribalda Delgado
2016-07-15 17:58 ` Hans Verkuil
2016-07-15 18:12 ` Hans Verkuil
2016-07-15 18:28 ` Hans Verkuil
2016-07-15 16:13 ` [PATCH v2 5/6] [media] vivid: Add support for HSV formats Ricardo Ribalda Delgado
2016-07-15 18:29 ` Hans Verkuil
2016-07-15 16:13 ` [PATCH v2 6/6] [media] vivid: Rename variable Ricardo Ribalda Delgado
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