linux-kernel - Re: [PATCH] media: v4l: Add packed YUV444 24bpp pixel format

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Date:   Thu, 11 Jul 2019 10:18:08 +0200
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     Mirela Rabulea <mirela.rabulea@....com>
Cc:     mchehab@...nel.org, hverkuil-cisco@...all.nl,
        vivek.kasireddy@...el.com, sakari.ailus@...ux.intel.com,
        s.nawrocki@...sung.com, niklas.soderlund+renesas@...natech.se,
        ezequiel@...labora.com, boris.brezillon@...labora.com,
        robert.chiras@....com, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-imx@....com
Subject: Re: [PATCH] media: v4l: Add packed YUV444 24bpp pixel format

Hi,

On Wed 03 Jul 19, 18:15, Mirela Rabulea wrote:
> The added format is V4L2_PIX_FMT_YUV24, this is a packed
> YUV 4:4:4 format, with 8 bits for each component, 24 bits
> per sample.
> 
> This format is used by the i.MX 8QuadMax and i.MX 8DualXPlus/8QuadXPlus
> JPEG encoder/decoder.

So this format is not aligned to 32-bit words at all and we can expect
to see cases where a single 32-bit word contains data for two pixels?

Nothing wrong with that, just checking whether I understood this right :)

Cheers,

Paul

> Signed-off-by: Mirela Rabulea <mirela.rabulea@....com>
> ---
>  Documentation/media/uapi/v4l/pixfmt-packed-yuv.rst | 37 +++++++++++++++++++++-
>  drivers/media/v4l2-core/v4l2-ioctl.c               |  1 +
>  include/uapi/linux/videodev2.h                     |  1 +
>  3 files changed, 38 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/media/uapi/v4l/pixfmt-packed-yuv.rst b/Documentation/media/uapi/v4l/pixfmt-packed-yuv.rst
> index 41b60fa..5750ff6 100644
> --- a/Documentation/media/uapi/v4l/pixfmt-packed-yuv.rst
> +++ b/Documentation/media/uapi/v4l/pixfmt-packed-yuv.rst
> @@ -17,7 +17,8 @@ Description
>  ===========
>  
>  Similar to the packed RGB formats these formats store the Y, Cb and Cr
> -component of each pixel in one 16 or 32 bit word.
> +component of each pixel next to each other in memory. They occupy 16, 24 or 32
> +bits per pixel.
>  
>  
>  .. raw:: latex
> @@ -157,6 +158,40 @@ component of each pixel in one 16 or 32 bit word.
>  
>        -  :cspan:`15`
>  
> +    * .. _V4L2-PIX-FMT-YUV24:
> +
> +      - ``V4L2_PIX_FMT_YUV24``
> +      - 'YUV3'
> +
> +      - Y'\ :sub:`7`
> +      - Y'\ :sub:`6`
> +      - Y'\ :sub:`5`
> +      - Y'\ :sub:`4`
> +      - Y'\ :sub:`3`
> +      - Y'\ :sub:`2`
> +      - Y'\ :sub:`1`
> +      - Y'\ :sub:`0`
> +
> +      - Cb\ :sub:`7`
> +      - Cb\ :sub:`6`
> +      - Cb\ :sub:`5`
> +      - Cb\ :sub:`4`
> +      - Cb\ :sub:`3`
> +      - Cb\ :sub:`2`
> +      - Cb\ :sub:`1`
> +      - Cb\ :sub:`0`
> +
> +      - Cr\ :sub:`7`
> +      - Cr\ :sub:`6`
> +      - Cr\ :sub:`5`
> +      - Cr\ :sub:`4`
> +      - Cr\ :sub:`3`
> +      - Cr\ :sub:`2`
> +      - Cr\ :sub:`1`
> +      - Cr\ :sub:`0`
> +
> +      -  :cspan:`7`
> +
>      * .. _V4L2-PIX-FMT-YUV32:
>  
>        - ``V4L2_PIX_FMT_YUV32``
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index b1f4b99..9bb6579 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1215,6 +1215,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>  	case V4L2_PIX_FMT_YUV444:	descr = "16-bit A/XYUV 4-4-4-4"; break;
>  	case V4L2_PIX_FMT_YUV555:	descr = "16-bit A/XYUV 1-5-5-5"; break;
>  	case V4L2_PIX_FMT_YUV565:	descr = "16-bit YUV 5-6-5"; break;
> +	case V4L2_PIX_FMT_YUV24:	descr = "24-bit YUV 4:4:4 8-8-8"; break;
>  	case V4L2_PIX_FMT_YUV32:	descr = "32-bit A/XYUV 8-8-8-8"; break;
>  	case V4L2_PIX_FMT_AYUV32:	descr = "32-bit AYUV 8-8-8-8"; break;
>  	case V4L2_PIX_FMT_XYUV32:	descr = "32-bit XYUV 8-8-8-8"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 9d9705c..752dd33 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -577,6 +577,7 @@ struct v4l2_pix_format {
>  #define V4L2_PIX_FMT_YUV444  v4l2_fourcc('Y', '4', '4', '4') /* 16  xxxxyyyy uuuuvvvv */
>  #define V4L2_PIX_FMT_YUV555  v4l2_fourcc('Y', 'U', 'V', 'O') /* 16  YUV-5-5-5     */
>  #define V4L2_PIX_FMT_YUV565  v4l2_fourcc('Y', 'U', 'V', 'P') /* 16  YUV-5-6-5     */
> +#define V4L2_PIX_FMT_YUV24   v4l2_fourcc('Y', 'U', 'V', '3') /* 24  YUV-8-8-8     */
>  #define V4L2_PIX_FMT_YUV32   v4l2_fourcc('Y', 'U', 'V', '4') /* 32  YUV-8-8-8-8   */
>  #define V4L2_PIX_FMT_AYUV32  v4l2_fourcc('A', 'Y', 'U', 'V') /* 32  AYUV-8-8-8-8  */
>  #define V4L2_PIX_FMT_XYUV32  v4l2_fourcc('X', 'Y', 'U', 'V') /* 32  XYUV-8-8-8-8  */
> -- 
> 2.7.4
> 

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com