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1.. SPDX-License-Identifier: GPL-2.02 3.. include:: <isonum.txt>4 5ASPEED video driver6===================7 8ASPEED Video Engine found on AST2400/2500/2600 SoC supports high performance9video compressions with a wide range of video quality and compression ratio10options. The adopted compressing algorithm is a modified JPEG algorithm.11 12There are 2 types of compressions in this IP.13 14* JPEG JFIF standard mode: for single frame and management compression15* ASPEED proprietary mode: for multi-frame and differential compression.16 Support 2-pass (high quality) video compression scheme (Patent pending by17 ASPEED). Provide visually lossless video compression quality or to reduce18 the network average loading under intranet KVM applications.19 20VIDIOC_S_FMT can be used to choose which format you want. V4L2_PIX_FMT_JPEG21stands for JPEG JFIF standard mode; V4L2_PIX_FMT_AJPG stands for ASPEED22proprietary mode.23 24More details on the ASPEED video hardware operations can be found in25*chapter 6.2.16 KVM Video Driver* of SDK_User_Guide which available on26`github <https://github.com/AspeedTech-BMC/openbmc/releases/>`__.27 28The ASPEED video driver implements the following driver-specific control:29 30``V4L2_CID_ASPEED_HQ_MODE``31---------------------------32 Enable/Disable ASPEED's High quality mode. This is a private control33 that can be used to enable high quality for aspeed proprietary mode.34 35.. flat-table::36 :header-rows: 037 :stub-columns: 038 :widths: 1 439 40 * - ``(0)``41 - ASPEED HQ mode is disabled.42 * - ``(1)``43 - ASPEED HQ mode is enabled.44 45``V4L2_CID_ASPEED_HQ_JPEG_QUALITY``46-----------------------------------47 Define the quality of ASPEED's High quality mode. This is a private control48 that can be used to decide compression quality if High quality mode enabled49 . Higher the value, better the quality and bigger the size.50 51.. flat-table::52 :header-rows: 053 :stub-columns: 054 :widths: 1 455 56 * - ``(1)``57 - minimum58 * - ``(12)``59 - maximum60 * - ``(1)``61 - step62 * - ``(1)``63 - default64 65**Copyright** |copy| 2022 ASPEED Technology Inc.66