Hi Jammy, 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@xxxxxxxxxxxxxx> > --- > 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? -- Regards, Sakari Ailus
