Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     linux-media@vger.kernel.org, hverkuil@xs4all.nl,
        hans.verkuil@cisco.com, kernel@collabora.com,
        linux-kernel@vger.kernel.org
References: <20210122182723.327438-1-helen.koike@collabora.com>
 <YAvyu6AvEmZy6WRq@pendragon.ideasonboard.com>
From:   Helen Koike <helen.koike@collabora.com>
Message-ID: <7f650d51-d419-53cc-0ad1-b241a10ab801@collabora.com>
Date:   Mon, 25 Jan 2021 10:57:15 -0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.6.1
MIME-Version: 1.0
In-Reply-To: <YAvyu6AvEmZy6WRq@pendragon.ideasonboard.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 1/23/21 6:56 AM, Laurent Pinchart wrote:
> Hi Helen,
> 
> Thank you for the patch.
> 
> On Fri, Jan 22, 2021 at 03:27:23PM -0300, Helen Koike wrote:
>> YUV 4:4:4 is not subsampled, fix this in the docs.
>>
>> Fixes: da785536e007 ("media: doc: pixfmt-yuv: Move all semi-planar YUV formats to common file")
>> Signed-off-by: Helen Koike <helen.koike@collabora.com>
>> ---
>>  Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
>> index 7d4d39201a3f..bcb4ef24c334 100644
>> --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
>> +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
>> @@ -396,8 +396,8 @@ number of lines as the luma plane.
>>  NV24 and NV42
>>  -------------
>>  
>> -Semi-planar YUV 4:4:4 formats. The chroma plane is subsampled by 2 in the
>> -horizontal direction. Chroma lines contain half the number of pixels and the
>> +Semi-planar YUV 4:4:4 formats. No sub-sampling.
> 
> "The chroma plane is not subsampled." ?

Ack.

> 
>> +Chroma lines contain the same number of pixels and the
>>  same number of bytes as luma lines, and the chroma plane contains the same
>>  number of lines as the luma plane.
> 
> That's not quite right, the chroma lines contain twice the number of
> pixels and bytes, as there's one Cb and one Cr value in the chroma line
> for each Y value in the luma line.
> 
> 
> Maybe the text could be reflowed ?
> 

Ack.

I'll submit v2 updating the text.

Thanks,
Helen