Hi Jammy, Thanks for the update. On Wed, Sep 21, 2022 at 10:51:09AM +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. 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> > --- > .../userspace-api/media/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/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst > index 0ff68cd8cf62..f62bc76d606f 100644 > --- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst > +++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst > @@ -258,6 +258,23 @@ please make a proposal on the linux-media mailing list. > and it is used by various multimedia hardware blocks like GPU, display > controllers, ISP and video accelerators. > It contains four planes for progressive video. > + * .. _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/>`__ This is better than the previous versions. Can you still run $ scripts/checkpatch.pl --strict --max-line-length=80 ? On the decoder --- which values is the user supposed to use for mode_420, selector and advance_selector parameters? I think this needs to be documented. > .. raw:: latex > > \normalsize > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c > index a1a1b51ac599..c72bc3410bee 100644 > --- a/drivers/media/v4l2-core/v4l2-ioctl.c > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c > @@ -1497,6 +1497,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt) > case V4L2_PIX_FMT_MT21C: descr = "Mediatek Compressed Format"; break; > case V4L2_PIX_FMT_QC08C: descr = "QCOM Compressed 8-bit Format"; break; > case V4L2_PIX_FMT_QC10C: descr = "QCOM Compressed 10-bit 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 86cae23cc446..870a7e5ef8ca 100644 > --- a/include/uapi/linux/videodev2.h > +++ b/include/uapi/linux/videodev2.h > @@ -775,6 +775,7 @@ struct v4l2_pix_format { > #define V4L2_PIX_FMT_HI240 v4l2_fourcc('H', 'I', '2', '4') /* BTTV 8-bit dithered RGB */ > #define V4L2_PIX_FMT_QC08C v4l2_fourcc('Q', '0', '8', 'C') /* Qualcomm 8-bit compressed */ > #define V4L2_PIX_FMT_QC10C v4l2_fourcc('Q', '1', '0', 'C') /* Qualcomm 10-bit compressed */ > +#define V4L2_PIX_FMT_AJPG v4l2_fourcc('A', 'J', 'P', 'G') /* Aspeed JPEG */ > > /* 10bit raw 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 */ -- Kind regards, Sakari Ailus
