1. 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.

The ASPEED video driver implements the following driver-specific control:


Enable/Disable ASPEED's High quality mode. This is a private control that can be used to enable high quality for aspeed proprietary mode.


ASPEED HQ mode is disabled.


ASPEED HQ mode is enabled.


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.









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