@@ -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
@@ -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;
@@ -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 */
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> --- v10: - no update v9: - Rebase on new kernel v8: - Add decoder information for aspeed-jpeg v7: - Add more information for aspeed-jpeg v6: - Update description for new format, aspeed-jpeg, in Documentation. v5: - no update v4: - new --- .../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(+)