Re: [PATCH v2] media: Add P010LE video format

From: Hans Verkuil
Date: Mon May 09 2022 - 05:51:05 EST

Hi Benjamin,

On 4/21/22 14:43, Benjamin Gaignard wrote:
> P010LE is a YUV format with 16-bits per pixel with interleaved UV.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> Acked-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
> ---
> version 2:
> - Fix Hans's remarks
> - Add 'LE' suffix to pixel name since P010BE can also exist

I don't think you should do this. By default formats are little endian,
unless explicitly stated otherwise. So big endian formats typically
have a _BE suffix, and they use v4l2_fourcc_be() instead of v4l2_fourcc().

This format is standard little endian, so I would just drop the LE bit.

>
> .../media/v4l/pixfmt-yuv-planar.rst | 53 +++++++++++++++++++
> 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, 56 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> index 8dff5906639b..b9dd4f376fe3 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> @@ -109,6 +109,13 @@ All components are stored with the same number of bits per component.
> - Cb, Cr
> - No
> - 16x16 tiles
> + * - V4L2_PIX_FMT_P010LE
> + - 'P010'
> + - 16
> + - 4:2:0
> + - Cb, Cr
> + - No
> + - Linear
> * - V4L2_PIX_FMT_NV16
> - 'NV16'
> - 8
> @@ -171,6 +178,7 @@ horizontally.
> .. _V4L2-PIX-FMT-NV21:
> .. _V4L2-PIX-FMT-NV12M:
> .. _V4L2-PIX-FMT-NV21M:
> +.. _V4L2-PIX-FMT-P010LE:
>
> NV12, NV21, NV12M and NV21M
> ---------------------------
> @@ -519,6 +527,51 @@ number of lines as the luma plane.
> - Cb\ :sub:`33`
> - Cr\ :sub:`33`
>
> +.. _V4L2_PIX_FMT_P010LE:
> +
> +P010LE
> +------
> +
> +Like NV12 with 16 bits per component, data in the 10 high bits, zeros in the 6 low bits, arranged in little endian order

Here it is fine to mention little endian, it's just the fourcc name I have a problem with.

Regards,

Hans


> +
> +.. flat-table:: Sample 4x4 P010LE Image
> + :header-rows: 0
> + :stub-columns: 0
> +
> + * - start + 0:
> + - Y'\ :sub:`00`
> + - Y'\ :sub:`01`
> + - Y'\ :sub:`02`
> + - Y'\ :sub:`03`
> + * - start + 8:
> + - Y'\ :sub:`10`
> + - Y'\ :sub:`11`
> + - Y'\ :sub:`12`
> + - Y'\ :sub:`13`
> + * - start + 16:
> + - Y'\ :sub:`20`
> + - Y'\ :sub:`21`
> + - Y'\ :sub:`22`
> + - Y'\ :sub:`23`
> + * - start + 24:
> + - Y'\ :sub:`30`
> + - Y'\ :sub:`31`
> + - Y'\ :sub:`32`
> + - Y'\ :sub:`33`
> + * - start + 32:
> + - Cb\ :sub:`00`
> + - Cr\ :sub:`00`
> + - Cb\ :sub:`01`
> + - Cr\ :sub:`01`
> + * - start + 40:
> + - Cb\ :sub:`10`
> + - Cr\ :sub:`10`
> + - Cb\ :sub:`11`
> + - Cr\ :sub:`11`
> +
> +.. raw:: latex
> +
> + \endgroup
>
> Fully Planar YUV Formats
> ========================
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index df34b2a283bc..bc73526c41b9 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -266,6 +266,7 @@ const struct v4l2_format_info *v4l2_format_info(u32 format)
> { .format = V4L2_PIX_FMT_NV61, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 2, .vdiv = 1 },
> { .format = V4L2_PIX_FMT_NV24, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 1, .vdiv = 1 },
> { .format = V4L2_PIX_FMT_NV42, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 1, .vdiv = 1 },
> + { .format = V4L2_PIX_FMT_P010LE, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 2, 2, 0, 0 }, .hdiv = 2, .vdiv = 1 },
>
> { .format = V4L2_PIX_FMT_YUV410, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 3, .bpp = { 1, 1, 1, 0 }, .hdiv = 4, .vdiv = 4 },
> { .format = V4L2_PIX_FMT_YVU410, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 3, .bpp = { 1, 1, 1, 0 }, .hdiv = 4, .vdiv = 4 },
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 96e307fe3aab..2ba3440099d0 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1301,6 +1301,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> case V4L2_PIX_FMT_NV61: descr = "Y/CrCb 4:2:2"; break;
> case V4L2_PIX_FMT_NV24: descr = "Y/CbCr 4:4:4"; break;
> case V4L2_PIX_FMT_NV42: descr = "Y/CrCb 4:4:4"; break;
> + case V4L2_PIX_FMT_P010LE: descr = "16-bit Y/CrCb 4:2:0"; break;
> case V4L2_PIX_FMT_NV12_4L4: descr = "Y/CbCr 4:2:0 (4x4 Linear)"; break;
> case V4L2_PIX_FMT_NV12_16L16: descr = "Y/CbCr 4:2:0 (16x16 Linear)"; break;
> case V4L2_PIX_FMT_NV12_32L32: descr = "Y/CbCr 4:2:0 (32x32 Linear)"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 4c09969e7112..92822a80a12e 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -601,6 +601,7 @@ struct v4l2_pix_format {
> #define V4L2_PIX_FMT_NV61 v4l2_fourcc('N', 'V', '6', '1') /* 16 Y/CrCb 4:2:2 */
> #define V4L2_PIX_FMT_NV24 v4l2_fourcc('N', 'V', '2', '4') /* 24 Y/CbCr 4:4:4 */
> #define V4L2_PIX_FMT_NV42 v4l2_fourcc('N', 'V', '4', '2') /* 24 Y/CrCb 4:4:4 */
> +#define V4L2_PIX_FMT_P010LE v4l2_fourcc('P', '0', '1', '0') /* 16 Y/CbCr 4:2:0 16-bit per pixel, little endian*/
>
> /* two non contiguous planes - one Y, one Cr + Cb interleaved */
> #define V4L2_PIX_FMT_NV12M v4l2_fourcc('N', 'M', '1', '2') /* 12 Y/CbCr 4:2:0 */