[PATCH v5 05/10] media: v4l: Add definition for the Aspeed JPEG format
jammy_huang at aspeedtech.com
Fri Nov 19 20:37:47 AEDT 2021
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 at aspeedtech.com>
>>>> - no update
>>>> - 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
>>>> 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
>>>> and 16-aligned resolutions for the chrominance plane (with 2x2
>>>> + * .. _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:
> 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,
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