Message-ID: <950e020b969f25e9795ee3ad3e2265c4b3427407.camel@ndufresne.ca>
Subject: Re: [PATCH v2 03/10] media: Add YUYV_12 video format
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     Ming Qian <ming.qian@nxp.com>, mchehab@kernel.org,
        mirela.rabulea@oss.nxp.com, hverkuil-cisco@xs4all.nl
Cc:     shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de,
        festevam@gmail.com, xiahong.bao@nxp.com, linux-imx@nxp.com,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Date:   Fri, 10 Feb 2023 11:28:46 -0500
In-Reply-To: <116656d22cd244ed0c1df74a1968518d4ab51c23.1675230665.git.ming.qian@nxp.com>
References: <cover.1675230665.git.ming.qian@nxp.com>
         <116656d22cd244ed0c1df74a1968518d4ab51c23.1675230665.git.ming.qian@nxp.com>
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Le mercredi 01 f=C3=A9vrier 2023 =C3=A0 14:02 +0800, Ming Qian a =C3=A9crit=
=C2=A0:
> YUYV_12 is a YUV format with 12-bits per component like YUYV,
> expanded to 16bits.
> Data in the 12 high bits, zeros in the 4 low bits,
> arranged in little endian order.

In following patches, you use a interesting naming convention:

  <comp order><word size>_<depth>

I think for this type of format this method works well. So I would like to
suggest calling this one:

  V4L2_PIX_FMT_YUYV64_12

Let me know what you think ?


>=20
> Signed-off-by: Ming Qian <ming.qian@nxp.com>
> ---
>  .../media/v4l/pixfmt-packed-yuv.rst           | 42 +++++++++++++++++++
>  drivers/media/v4l2-core/v4l2-common.c         |  1 +
>  drivers/media/v4l2-core/v4l2-ioctl.c          |  1 +
>  include/uapi/linux/videodev2.h                |  1 +
>  4 files changed, 45 insertions(+)
>=20
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst =
b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
> index bf283a1b5581..bb7169b2cc8d 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
> @@ -341,6 +341,48 @@ components horizontally by 2, storing 2 pixels in 4 =
bytes.
> =20
>      \normalsize
> =20
> +The next lists the packed YUV 4:2:2 formats with more than 8 bits per co=
mponent.
> +expand the bits per component to 16 bits, data in the high bits, zeros i=
n the low bits,
> +arranged in little endian order. storing 2 pixels in 8 bytes.
> +
> +.. raw:: latex
> +
> +    \footnotesize
> +
> +.. tabularcolumns:: |p{3.4cm}|p{1.2cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|p{0.8c=
m}|p{0.8cm}|p{0.8cm}|p{0.8cm}|p{0.8cm}|
> +
> +.. flat-table:: Packed YUV 4:2:2 Formats (more than 8bpc)
> +    :header-rows: 1
> +    :stub-columns: 0
> +
> +    * - Identifier
> +      - Code
> +      - Byte 1-0
> +      - Byte 3-2
> +      - Byte 5-4
> +      - Byte 7-6
> +      - Byte 9-8
> +      - Byte 11-10
> +      - Byte 13-12
> +      - Byte 15-14
> +    * .. _V4L2-PIX-FMT-YUYV-12:
> +
> +      - ``V4L2_PIX_FMT_YUYV_12``
> +      - 'Y212'
> +
> +      - Y'\ :sub:`0`
> +      - Cb\ :sub:`0`
> +      - Y'\ :sub:`1`
> +      - Cr\ :sub:`0`
> +      - Y'\ :sub:`2`
> +      - Cb\ :sub:`2`
> +      - Y'\ :sub:`3`
> +      - Cr\ :sub:`2`
> +
> +.. raw:: latex
> +
> +    \normalsize
> +
>  **Color Sample Location:**
>  Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
>  horizontally.
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-c=
ore/v4l2-common.c
> index a5e8ba370d33..3a882fb71227 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -258,6 +258,7 @@ const struct v4l2_format_info *v4l2_format_info(u32 f=
ormat)
>  		{ .format =3D V4L2_PIX_FMT_YVYU,    .pixel_enc =3D V4L2_PIXEL_ENC_YUV,=
 .mem_planes =3D 1, .comp_planes =3D 1, .bpp =3D { 2, 0, 0, 0 }, .hdiv =3D =
2, .vdiv =3D 1 },
>  		{ .format =3D V4L2_PIX_FMT_UYVY,    .pixel_enc =3D V4L2_PIXEL_ENC_YUV,=
 .mem_planes =3D 1, .comp_planes =3D 1, .bpp =3D { 2, 0, 0, 0 }, .hdiv =3D =
2, .vdiv =3D 1 },
>  		{ .format =3D V4L2_PIX_FMT_VYUY,    .pixel_enc =3D V4L2_PIXEL_ENC_YUV,=
 .mem_planes =3D 1, .comp_planes =3D 1, .bpp =3D { 2, 0, 0, 0 }, .hdiv =3D =
2, .vdiv =3D 1 },
> +		{ .format =3D V4L2_PIX_FMT_YUYV_12, .pixel_enc =3D V4L2_PIXEL_ENC_YUV,=
 .mem_planes =3D 1, .comp_planes =3D 1, .bpp =3D { 4, 0, 0, 0 }, .hdiv =3D =
2, .vdiv =3D 1 },
> =20
>  		/* YUV planar formats */
>  		{ .format =3D V4L2_PIX_FMT_NV12,    .pixel_enc =3D V4L2_PIXEL_ENC_YUV,=
 .mem_planes =3D 1, .comp_planes =3D 2, .bpp =3D { 1, 2, 0, 0 }, .hdiv =3D =
2, .vdiv =3D 2 },
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-co=
re/v4l2-ioctl.c
> index 0ee730aa6cc7..928acb9d13ec 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1342,6 +1342,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *f=
mt)
>  	case V4L2_PIX_FMT_YUV420:	descr =3D "Planar YUV 4:2:0"; break;
>  	case V4L2_PIX_FMT_HI240:	descr =3D "8-bit Dithered RGB (BTTV)"; break;
>  	case V4L2_PIX_FMT_M420:		descr =3D "YUV 4:2:0 (M420)"; break;
> +	case V4L2_PIX_FMT_YUYV_12:	descr =3D "12-bit Depth YUYV 4:2:2"; break;
>  	case V4L2_PIX_FMT_NV12:		descr =3D "Y/UV 4:2:0"; break;
>  	case V4L2_PIX_FMT_NV21:		descr =3D "Y/VU 4:2:0"; break;
>  	case V4L2_PIX_FMT_NV16:		descr =3D "Y/UV 4:2:2"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev=
2.h
> index 3d8f89bff33c..01fd233ff681 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -618,6 +618,7 @@ struct v4l2_pix_format {
>  #define V4L2_PIX_FMT_YUVA32  v4l2_fourcc('Y', 'U', 'V', 'A') /* 32  YUVA=
-8-8-8-8  */
>  #define V4L2_PIX_FMT_YUVX32  v4l2_fourcc('Y', 'U', 'V', 'X') /* 32  YUVX=
-8-8-8-8  */
>  #define V4L2_PIX_FMT_M420    v4l2_fourcc('M', '4', '2', '0') /* 12  YUV =
4:2:0 2 lines y, 1 line uv interleaved */
> +#define V4L2_PIX_FMT_YUYV_12     v4l2_fourcc('Y', '2', '1', '2') /* 32  =
YUYV 12-bit per component */
> =20
>  /* two planes -- one Y, one Cr + Cb interleaved  */
>  #define V4L2_PIX_FMT_NV12    v4l2_fourcc('N', 'V', '1', '2') /* 12  Y/Cb=
Cr 4:2:0  */