Re: [PATCH v8 1/4] media: v4l: Add definition for the Aspeed JPEG format

From: Hans Verkuil
Date: Fri Jan 14 2022 - 03:11:49 EST


On 24/12/2021 02:27, Jammy Huang wrote:
> This introduces support for the Aspeed JPEG format, where the new frame
> can refer to previous frame to reduce the amount of compressed data. The
> concept is similar to I/P frame of video compression. It will compare the
> new frame with previous one to decide which macroblock's data is
> changed, and only the changed macroblocks will be compressed.
>
> This Aspeed JPEG format is used by the video engine on Aspeed platforms,
> which is generally adapted for remote KVM.
>
> Signed-off-by: Jammy Huang <jammy_huang@xxxxxxxxxxxxxx>
> ---
> v8:
> - Add decoder information for aspeed-jpeg
> v7:
> - Add more information for aspeed-jpeg
> v6:
> - Update description for new format, aspeed-jpeg, in Documentation.
> v5:
> - no update
> v4:
> - new
> ---
> .../media/uapi/v4l/pixfmt-reserved.rst | 17 +++++++++++++++++
> drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
> include/uapi/linux/videodev2.h | 1 +
> 3 files changed, 19 insertions(+)
>
> diff --git a/Documentation/media/uapi/v4l/pixfmt-reserved.rst b/Documentation/media/uapi/v4l/pixfmt-reserved.rst

This is the wrong file! It should be:

Documentation/userspace-api/media/v4l/pixfmt-reserved.rst

Regards,

Hans

> index b2cd155e691b..1d0dc8d86ed7 100644
> --- a/Documentation/media/uapi/v4l/pixfmt-reserved.rst
> +++ b/Documentation/media/uapi/v4l/pixfmt-reserved.rst
> @@ -264,6 +264,23 @@ please make a proposal on the linux-media mailing list.
> of tiles, resulting in 32-aligned resolutions for the luminance plane
> and 16-aligned resolutions for the chrominance plane (with 2x2
> subsampling).
> + * .. _V4L2-PIX-FMT-AJPG:
> +
> + - ``V4L2_PIX_FMT_AJPG``
> + - 'AJPG'
> + - ASPEED JPEG format used by the aspeed-video driver on Aspeed platforms,
> + which is generally adapted for remote KVM.
> + On each frame compression, I will compare the new frame with previous
> + one to decide which macroblock's data is changed, and only the changed
> + macroblocks will be compressed.
> +
> + The implementation is based on AST2600 A3 datasheet, revision 0.9, which
> + is not publicly available. Or you can reference Video stream data format
> + – ASPEED mode compression of SDK_User_Guide which available on
> + AspeedTech-BMC/openbmc/releases.
> +
> + Decoder's implementation can be found here,
> + `https://github.com/AspeedTech-BMC/aspeed_codec/ <https://github.com/AspeedTech-BMC/aspeed_codec/>`__
>
> .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
>
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 24db33f803c0..00dde01d2f97 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1378,6 +1378,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> case V4L2_PIX_FMT_S5C_UYVY_JPG: descr = "S5C73MX interleaved UYVY/JPEG"; break;
> case V4L2_PIX_FMT_MT21C: descr = "Mediatek Compressed Format"; break;
> case V4L2_PIX_FMT_SUNXI_TILED_NV12: descr = "Sunxi Tiled NV12 Format"; break;
> + case V4L2_PIX_FMT_AJPG: descr = "Aspeed JPEG"; break;
> default:
> if (fmt->description[0])
> return;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 3210b3c82a4a..994eb6155ea9 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -726,6 +726,7 @@ struct v4l2_pix_format {
> #define V4L2_PIX_FMT_INZI v4l2_fourcc('I', 'N', 'Z', 'I') /* Intel Planar Greyscale 10-bit and Depth 16-bit */
> #define V4L2_PIX_FMT_SUNXI_TILED_NV12 v4l2_fourcc('S', 'T', '1', '2') /* Sunxi Tiled NV12 Format */
> #define V4L2_PIX_FMT_CNF4 v4l2_fourcc('C', 'N', 'F', '4') /* Intel 4-bit packed depth confidence information */
> +#define V4L2_PIX_FMT_AJPG v4l2_fourcc('A', 'J', 'P', 'G') /* Aspeed JPEG */
>
> /* 10bit raw bayer packed, 32 bytes for every 25 pixels, last LSB 6 bits unused */
> #define V4L2_PIX_FMT_IPU3_SBGGR10 v4l2_fourcc('i', 'p', '3', 'b') /* IPU3 packed 10-bit BGGR bayer */