From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>, linux-media@vger.kernel.org
Subject: Re: [PATCH] v4l: Clarify RGB666 pixel format definition
Date: Tue, 10 Nov 2015 00:21:13 +0200 [thread overview]
Message-ID: <1467109.0hyysKvb3u@avalon> (raw)
In-Reply-To: <4301993.tc7nBMPXQH@avalon>
Hi Sylwester,
Reviving a "slightly" old discussion.
On Wednesday 29 October 2014 13:45:46 Laurent Pinchart wrote:
> On Tuesday 09 September 2014 16:45:17 Sylwester Nawrocki wrote:
> > On 09/09/14 15:18, Laurent Pinchart wrote:
> >> On Tuesday 22 July 2014 00:44:34 Hans Verkuil wrote:
> >>> On 07/22/2014 12:30 AM, Laurent Pinchart wrote:
> >>>> 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?
[snip]
> > My apologies, I didn't notice this earlier.
> >
> > In case of S5P/Exynos FIMC the format is:
> >
> > Byte 0 Byte 1 Byte 2 Byte 3
> >
> > BBBBBBGG GGGGRRRR RR------ --------
> >
> > i.e. 4 byte per pixel, with 14-bit padding (don't care bits).
> >
> > As far as S3C6410 CAMIF is concerned it's hard to say. I primarily
> > developed the s3c-camif driver for S3C2440 SoC, which doesn't support
> > BGR666 format. I merged some patches from others adding s3c6410 support,
> > before sending upstream.
> >
> > Nevertheless, looking at the S3C CAMIF datasheet the RGB666 format seems
> > identical with the FIMC one. See [1], chapter "20.7.4 MEMORY STORING
> > METHOD". This would make sense, since the S5P/Exynos FIMC is basically
> > a significantly evolved S3C CAMIF AFAICT.
>
> Looking at the figure, I would understand RGB666 as follows
>
> Bits 31 24|23 16|15 8|7 0
> ---- ----|---- -- R5 R4|R3 R2 R1 R0 G5 G4 G3 G2|G1 G0 B5 B4 B3 B2 B1 B0
>
> Assuming little endian memory format, that would thus be
>
> Byte 0 Byte 1 Byte 2 Byte 3
>
> GGBBBBBB RRRRGGGG ------RR --------
>
> If the memory format was big endian it would instead be
>
> -------- ------RR RRRRGGGG GGBBBBBB
>
> > [1] http://www.arm9board.net/download/OK6410/docs/S3C6410X.pdf
Did I understand something incorrectly ?
--
Regards,
Laurent Pinchart
prev parent reply other threads:[~2015-11-09 22:21 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
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 [this message]
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