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

From: Paul Kocialkowski
Date: Thu Jul 11 2019 - 04:23:09 EST


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@xxxxxxx>
> ---
> 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