Based on kernel version 6.8. Page generated on 2024-03-11 21:26 EST.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | .. SPDX-License-Identifier: GPL-2.0 .. include:: <isonum.txt> ASPEED video driver =================== ASPEED Video Engine found on AST2400/2500/2600 SoC supports high performance video compressions with a wide range of video quality and compression ratio options. The adopted compressing algorithm is a modified JPEG algorithm. There are 2 types of compressions in this IP. * JPEG JFIF standard mode: for single frame and management compression * ASPEED proprietary mode: for multi-frame and differential compression. Support 2-pass (high quality) video compression scheme (Patent pending by ASPEED). Provide visually lossless video compression quality or to reduce the network average loading under intranet KVM applications. VIDIOC_S_FMT can be used to choose which format you want. V4L2_PIX_FMT_JPEG stands for JPEG JFIF standard mode; V4L2_PIX_FMT_AJPG stands for ASPEED proprietary mode. More details on the ASPEED video hardware operations can be found in *chapter 6.2.16 KVM Video Driver* of SDK_User_Guide which available on `github <https://github.com/AspeedTech-BMC/openbmc/releases/>`__. The ASPEED video driver implements the following driver-specific control: ``V4L2_CID_ASPEED_HQ_MODE`` --------------------------- Enable/Disable ASPEED's High quality mode. This is a private control that can be used to enable high quality for aspeed proprietary mode. .. flat-table:: :header-rows: 0 :stub-columns: 0 :widths: 1 4 * - ``(0)`` - ASPEED HQ mode is disabled. * - ``(1)`` - ASPEED HQ mode is enabled. ``V4L2_CID_ASPEED_HQ_JPEG_QUALITY`` ----------------------------------- Define the quality of ASPEED's High quality mode. This is a private control that can be used to decide compression quality if High quality mode enabled . Higher the value, better the quality and bigger the size. .. flat-table:: :header-rows: 0 :stub-columns: 0 :widths: 1 4 * - ``(1)`` - minimum * - ``(12)`` - maximum * - ``(1)`` - step * - ``(1)`` - default **Copyright** |copy| 2022 ASPEED Technology Inc. |