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SubjectRe: [PATCH v8 1/4] media: v4l: Add definition for the Aspeed JPEG format
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On 2022/1/17 上午 10:24, Joel Stanley wrote:
> On Mon, 17 Jan 2022 at 02:00, Jammy Huang <jammy_huang@aspeedtech.com> wrote:
>> Hi Hans,
>>
>> On 2022/1/14 下午 04:11, Hans Verkuil wrote:
>>> 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@aspeedtech.com>
>>>> ---
>>>> 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
>> Thanks, I just used git format-patch to generate the cover-letter and
>> didn't notice this.
>>
>> It looks like the file, pixfmt-reserved.rst, has different path in
>> different Linux kernel,
>>
>> * 5.4: Documentation/media/uapi/v4l/pixfmt-reserved.rst
>>
>> * 5.10/5.15: Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
>>
>> 5.4 is the one I based to submit the patches.
>>
>> Could you suggest the kernel that I should based to submit these patches??
> You should always submit based on the latest release.
>
> There are sometimes exceptions where you will base your patches on
> something even newer, but generally you should grab the latest.
>
> Be sure to re-test on the latest kernel before submitting.
OK, thank you.
>
> Cheers,
>
> Joel
>
>> I will need to change the number of V4L2_CID_USER_ASPEED_BASE per different
>>
>> linux kernel as well.
>>
>>> 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 */
>> --
>> Best Regards
>> Jammy
>>
--
Best Regards
Jammy

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