From: Hans Verkuil <hverkuil@xs4all.nl>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: linux-media@vger.kernel.org, Sylwester Nawrocki <s.nawrocki@samsung.com>
Subject: Re: [PATCH] v4l: Clarify RGB666 pixel format definition
Date: Tue, 22 Jul 2014 00:44:34 +0200 [thread overview]
Message-ID: <53CD97D2.1010408@xs4all.nl> (raw)
In-Reply-To: <1479223.veAhoGoXLY@avalon>
On 07/22/2014 12:30 AM, Laurent Pinchart wrote:
> Hi Hans,
>
> On Monday 21 July 2014 23:43:16 Hans Verkuil wrote:
>> On 07/21/2014 10:39 PM, Laurent Pinchart wrote:
>>> The RGB666 pixel format doesn't include an alpha channel. Document it as
>>> such.
>>>
>>> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>> ---
>>>
>>> .../DocBook/media/v4l/pixfmt-packed-rgb.xml | 20 +++++----------
>>> 1 file changed, 6 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml
>>> b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml index
>>> 32feac9..c47692a 100644
>>> --- a/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml
>>> +++ b/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml
>>> @@ -330,20 +330,12 @@ colorspace
>>> <constant>V4L2_COLORSPACE_SRGB</constant>.</para>>
>>> <entry></entry>
>>> <entry>r<subscript>1</subscript></entry>
>>> <entry>r<subscript>0</subscript></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> - <entry></entry>
>>> + <entry>-</entry>
>>> + <entry>-</entry>
>>> + <entry>-</entry>
>>> + <entry>-</entry>
>>> + <entry>-</entry>
>>> + <entry>-</entry>
>>
>> Just to clarify: BGR666 is a three byte format, not a four byte format?
>
> Well... :-)
>
> Three drivers seem to support the BGR666 in mainline : sh_veu, s3c-camif and
> exynos4-is. Further investigation shows that the sh_veu driver lists the
> BGR666 format internally but doesn't expose it to userspace and doesn't
> actually support it, so we're down to two drivers.
>
> Looking at the S3C6410 datasheet, it's unclear how the hardware stores RGB666
> pixels in memory. It could be either
>
> Byte 0 Byte 1 Byte 2 Byte 3
>
> -------- ------RR RRRRGGGG GGBBBBBB
>
> or
>
> GGBBBBBB RRRRGGGG ------RR --------
>
> None of those correspond to the RGB666 format defined in the spec.
>
> The Exynos4 FIMC isn't documented in the public datasheet, so I can't check
> how the format is defined.
>
> Furthermore, various Renesas video-related IP cores support many different
> RGB666 variants, on either 32 or 24 bits per pixel, with and without alpha.
>
> Beside a loud *sigh*, any comment ? :-)
You'll have to check with Samsung then. Sylwester, can you shed any light on
what this format *really* is?
Regards,
Hans
>
>>> </row>
>>> <row id="V4L2-PIX-FMT-BGR24">
>>> <entry><constant>V4L2_PIX_FMT_BGR24</constant></entry>
>
next prev parent reply other threads:[~2014-07-21 22:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-21 20:39 [PATCH] v4l: Clarify RGB666 pixel format definition Laurent Pinchart
2014-07-21 21:43 ` Hans Verkuil
2014-07-21 22:30 ` Laurent Pinchart
2014-07-21 22:44 ` Hans Verkuil [this message]
2014-09-09 13:18 ` Laurent Pinchart
2014-09-09 14:45 ` Sylwester Nawrocki
2014-10-29 11:45 ` Laurent Pinchart
2015-11-09 22:21 ` Laurent Pinchart
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