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media: v4l: Add definition for the Aspeed JPEG format

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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>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
This commit is contained in:
Jammy Huang 2022-10-28 10:35:50 +08:00 committed by Hans Verkuil
parent c4d344163c
commit 7a4b3770d6
3 changed files with 19 additions and 0 deletions
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17
Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
View file

@ -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,
`aspeed_codec <https://github.com/AspeedTech-BMC/aspeed_codec/>`__
.. raw:: latex
\normalsize

1
drivers/media/v4l2-core/v4l2-ioctl.c
View file

@ -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;

1
include/uapi/linux/videodev2.h
View file

@ -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 */