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SubjectRe: [PATCH 1/6] media: v4l2: Add NV15 pixel format
Hi Sebastian and Jonas,

Thank you for the patch.

On Wed, Jul 13, 2022 at 06:24:46PM +0200, Sebastian Fricke wrote:
> From: Jonas Karlman <jonas@kwiboo.se>
>
> Add the NV15 pixel format used by the Rockchip Video Decoder for 10-bit
> buffers.
>
> NV15 is a packed 10-bit 4:2:0 Y/CbCr format similar to P010 and P210 but
> has no padding between components. Instead, luminance and chrominance
> samples are grouped into 4s so that each group is packed into an integer
> number of bytes:
>
> YYYY = UVUV = 4 * 10 bits = 40 bits = 5 bytes
>
> The '15' suffix refers to the optimum effective bits per pixel which is
> achieved when the total number of luminance samples is a multiple of 8
> for NV15.
>
> Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
> Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
> ---
> .../media/v4l/pixfmt-yuv-planar.rst | 53 +++++++++++++++++++
> drivers/media/v4l2-core/v4l2-common.c | 2 +
> drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
> include/uapi/linux/videodev2.h | 1 +
> 4 files changed, 57 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> index a900ff66911a..42ab3fe4667f 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> @@ -79,6 +79,13 @@ All components are stored with the same number of bits per component.
> - Cr, Cb
> - Yes
> - Linear
> + * - V4L2_PIX_FMT_NV15
> + - 'NV15'
> + - 15
> + - 4:2:0
> + - Cb, Cr
> + - Yes
> + - Linear
> * - V4L2_PIX_FMT_NV12M
> - 'NM12'
> - 8
> @@ -176,6 +183,7 @@ horizontally.
>
> .. _V4L2-PIX-FMT-NV12:
> .. _V4L2-PIX-FMT-NV21:
> +.. _V4L2-PIX-FMT-NV15:
> .. _V4L2-PIX-FMT-NV12M:
> .. _V4L2-PIX-FMT-NV21M:
> .. _V4L2-PIX-FMT-P010:
> @@ -570,6 +578,51 @@ Data in the 10 high bits, zeros in the 6 low bits, arranged in little endian ord
> - Cb\ :sub:`11`
> - Cr\ :sub:`11`
>
> +.. _V4L2_PIX_FMT_NV15:
> +
> +NV15
> +----
> +
> +Like P010 but a packed 10-bit 4:2:0 semi-planar Y/CbCr format without padding between components.

"packed 10-bit semi-planar" sounds confusing, as "packed YUV" usually
refers to YUYV-style formats, but I'm not sure how to express that
better.

> +Instead, luminance and chrominance samples are grouped into 4s so that each group is packed into an integer
> +number of bytes:

Could you please wrap the description at 80 columns ?

> +YYYY = UVUV = 4 * 10 bits = 40 bits = 5 bytes
> +
> +.. flat-table:: Sample 4x4 NV15 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`

This doesn't look right. You need to describe the data at the bit level,
so show how the 10-bit samples are packed into bytes.

> +
> .. raw:: latex
>
> \endgroup
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index 1e38ad8906a2..23a0cb02ea3a 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -262,6 +262,8 @@ const struct v4l2_format_info *v4l2_format_info(u32 format)
> /* 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 },
> { .format = V4L2_PIX_FMT_NV21, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 2, .vdiv = 2 },
> + { .format = V4L2_PIX_FMT_NV15, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 5, 5, 0, 0 }, .hdiv = 2, .vdiv = 2,
> + .block_w = { 4, 2, 0, 0 }, .block_h = { 1, 1, 0, 0 } },
> { .format = V4L2_PIX_FMT_NV16, .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_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 },
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index e2526701294e..9e5510cb255e 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1302,6 +1302,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> case V4L2_PIX_FMT_M420: descr = "YUV 4:2:0 (M420)"; break;
> case V4L2_PIX_FMT_NV12: descr = "Y/CbCr 4:2:0"; break;
> case V4L2_PIX_FMT_NV21: descr = "Y/CrCb 4:2:0"; break;
> + case V4L2_PIX_FMT_NV15: descr = "10-bit Y/CbCr 4:2:0 (Packed)"; break;
> case V4L2_PIX_FMT_NV16: descr = "Y/CbCr 4:2:2"; break;
> case V4L2_PIX_FMT_NV61: descr = "Y/CrCb 4:2:2"; break;
> case V4L2_PIX_FMT_NV24: descr = "Y/CbCr 4:4:4"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 5a73b92ffe4d..47ff34d6b79f 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -598,6 +598,7 @@ struct v4l2_pix_format {
> /* two planes -- one Y, one Cr + Cb interleaved */
> #define V4L2_PIX_FMT_NV12 v4l2_fourcc('N', 'V', '1', '2') /* 12 Y/CbCr 4:2:0 */
> #define V4L2_PIX_FMT_NV21 v4l2_fourcc('N', 'V', '2', '1') /* 12 Y/CrCb 4:2:0 */
> +#define V4L2_PIX_FMT_NV15 v4l2_fourcc('N', 'V', '1', '5') /* 15 Y/CbCr 4:2:0 10-bit packed */
> #define V4L2_PIX_FMT_NV16 v4l2_fourcc('N', 'V', '1', '6') /* 16 Y/CbCr 4:2:2 */
> #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 */

--
Regards,

Laurent Pinchart

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