Messages in this thread | | | Date | Fri, 19 Nov 2021 17:37:47 +0800 | Subject | Re: [PATCH v5 05/10] media: v4l: Add definition for the Aspeed JPEG format | From | Jammy Huang <> |
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Dear Paul,
OK, thanks for your suggestion.
On 2021/11/19 下午 04:39, Paul Menzel wrote: > Dear Jammy, > > > Am 19.11.21 um 03:02 schrieb Jammy Huang: > >> On 2021/11/18 下午 08:33, Sakari Ailus wrote: >>> On Thu, Nov 18, 2021 at 03:40:26PM +0800, 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. 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. >>>> >>>> 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> >>>> --- >>>> v5: >>>> - no update >>>> v4: >>>> - new >>>> --- >>>> Documentation/media/uapi/v4l/pixfmt-reserved.rst | 12 ++++++++++++ >>>> drivers/media/v4l2-core/v4l2-ioctl.c | 1 + >>>> include/uapi/linux/videodev2.h | 1 + >>>> 3 files changed, 14 insertions(+) >>>> >>>> diff --git a/Documentation/media/uapi/v4l/pixfmt-reserved.rst >>>> b/Documentation/media/uapi/v4l/pixfmt-reserved.rst >>>> index b2cd155e691b..23c05063133d 100644 >>>> --- a/Documentation/media/uapi/v4l/pixfmt-reserved.rst >>>> +++ b/Documentation/media/uapi/v4l/pixfmt-reserved.rst >>>> @@ -264,6 +264,18 @@ 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. >>>> + >>>> + You could reference to chapter 36, Video Engine, of AST2600's datasheet >>>> + for more information. >>> Is this datasheet publicly available? Do you have a URL? >> Sorry, this datasheet is not publicly available. >> Hans mentioned this as well in the discussion below: >> >> https://lkml.org/lkml/2021/11/10/101 > If questions come up during review, please also add the answers to the > commit message of the next iteration. ;-) Maybe: > >> The implementation is based on datasheet *Name goes here*, revision >> X, which is not publicly available. > Kind regards, > > Paul
-- Best Regards Jammy
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