Re: [PATCH v4 04/10] media: Add YUV48_12 video format

[Hans Verkuil <hverkuil-cisco@xs4all.nl>]

On 14/03/2023 11:08, Ming Qian wrote:
> YUV48_12 is a YUV format with 12-bits per component like YUV24,
> expanded to 16bits.
> Data in the 12 high bits, zeros in the 4 low bits,
> arranged in little endian order.
> 
> Signed-off-by: Ming Qian <ming.qian@nxp.com>
> ---
>  .../media/v4l/pixfmt-packed-yuv.rst           | 28 +++++++++++++++++++
>  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, 31 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
> index 24a771542059..ed998d8341ff 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
> @@ -257,6 +257,34 @@ the second byte and Y'\ :sub:`7-0` in the third byte.
>      - The padding bits contain undefined values that must be ignored by all
>        applications and drivers.
>  
> +The next lists the packed YUV 4:4:4 formats with 12 bits per component.

next -> next table

> +expand the bits per component to 16 bits, data in the high bits, zeros in the low bits,

expand -> Expand

> +arranged in little endian order. storing 1 pixels in 6 bytes.

pixels -> pixel

> +
> +.. flat-table:: Packed YUV 4:4:4 Image Formats (12bpc)
> +    :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
> +
> +    * .. _V4L2-PIX-FMT-YUV48-12:
> +
> +      - ``V4L2_PIX_FMT_YUV48_12``
> +      - 'Y312'
> +
> +      - Y'\ :sub:`0`
> +      - Cb\ :sub:`0`
> +      - Cr\ :sub:`0`
> +      - Y'\ :sub:`1`
> +      - Cb\ :sub:`1`
> +      - Cr\ :sub:`1`
>  
>  4:2:2 Subsampling
>  =================
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index 21ace56fac04..da313a0637de 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -259,6 +259,7 @@ const struct v4l2_format_info *v4l2_format_info(u32 format)
>  		{ .format = V4L2_PIX_FMT_UYVY,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 1, .bpp = { 2, 0, 0, 0 }, .hdiv = 2, .vdiv = 1 },
>  		{ .format = V4L2_PIX_FMT_VYUY,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 1, .bpp = { 2, 0, 0, 0 }, .hdiv = 2, .vdiv = 1 },
>  		{ .format = V4L2_PIX_FMT_Y212,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 1, .bpp = { 4, 0, 0, 0 }, .hdiv = 2, .vdiv = 1 },
> +		{ .format = V4L2_PIX_FMT_YUV48_12, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 1, .bpp = { 6, 0, 0, 0 }, .hdiv = 1, .vdiv = 1 },
>  
>  		/* YUV planar formats */
>  		{ .format = V4L2_PIX_FMT_NV12,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 2, .vdiv = 2 },
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 2cb485643562..6543cda5815f 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1346,6 +1346,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>  	case V4L2_PIX_FMT_YUV420:	descr = "Planar YUV 4:2:0"; break;
>  	case V4L2_PIX_FMT_HI240:	descr = "8-bit Dithered RGB (BTTV)"; break;
>  	case V4L2_PIX_FMT_M420:		descr = "YUV 4:2:0 (M420)"; break;
> +	case V4L2_PIX_FMT_YUV48_12:	descr = "12-bit Depth YUV 4:4:4"; break;

How about: "12-bit YUYV 4:4:4 Packed"

By the way, I think these existing formats:

        case V4L2_PIX_FMT_Y210:         descr = "10-bit YUYV Packed"; break;
        case V4L2_PIX_FMT_Y212:         descr = "12-bit YUYV Packed"; break;
        case V4L2_PIX_FMT_Y216:         descr = "16-bit YUYV Packed"; break;

should be renamed to "10-bit YUYV 4:2:2 Packed"

>  	case V4L2_PIX_FMT_NV12:		descr = "Y/UV 4:2:0"; break;
>  	case V4L2_PIX_FMT_NV21:		descr = "Y/VU 4:2:0"; break;
>  	case V4L2_PIX_FMT_NV16:		descr = "Y/UV 4:2:2"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index db06d4c4f008..8a6430bc4a00 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -621,6 +621,7 @@ 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_YUV48_12    v4l2_fourcc('Y', '3', '1', '2') /* 48  YUV 4:4:4 12-bit per component */
>  
>  /*
>   * YCbCr packed format. For each Y2xx format, xx bits of valid data occupy the MSBs

Regards,

	Hans