ddcswitch

A Windows command-line tool to control monitors over DDC/CI: switch inputs, set brightness and contrast, and read or write any VCP feature without touching the monitor's buttons. Ships as a single NativeAOT executable with no .NET runtime dependency.

📚 Examples | 📝 Changelog

Installation

choco install ddcswitch

Or download ddcswitch.exe from Releases and put it on your PATH.

Build from source (.NET SDK 10.0.403 or later, as pinned in global.json, and the Visual Studio "Desktop development with C++" workload):

git clone https://github.com/markdwags/ddcswitch.git
cd ddcswitch
.\build.ps1                            # produces dist\ddcswitch.exe
dotnet test --project DDCSwitch.Tests  # run the unit tests (no monitor needed)

Usage

ddcswitch list                          # monitors, current input, DDC/CI status
ddcswitch info 0                        # EDID details
ddcswitch get 0 brightness              # read a feature
ddcswitch set 0 brightness 75%          # write a feature
ddcswitch set 0 input HDMI1             # switch input
ddcswitch toggle 0 HDMI1 DP1            # flip between two inputs (great for hotkeys)
ddcswitch get 0 0x10                    # raw VCP code
ddcswitch get 0                         # scan all VCP codes on one monitor
ddcswitch get all                       # scan every monitor

Selecting a monitor: use its index from list, or part of its name, model, hardware ID or display device, e.g. toggle VG270U HDMI1 DP1 or get DISPLAY2 input.

Inputs: HDMI1, HDMI2, DP1, DP2, DVI1, DVI2, VGA1, VGA2, or a hex code like 0x11.

Features: brightness, contrast, input, volume, mute, red-gain, green-gain, blue-gain, and more by name, or any VCP code 0x00–0xFF. Brightness, contrast and volume accept percentages.

Flags:

Flag	Effect
--json	Machine-readable output for scripts
--verbose	Extra EDID and brightness/contrast columns in list
--trace	Log every DDC/CI call with error code and timing to stderr (or set DDCSWITCH_TRACE=1)

Set NO_COLOR=1 for plain output without colors or icons.

Troubleshooting

• "No DDC/CI" or no response: make sure DDC/CI is enabled in the monitor's OSD menu, then run the command again with --trace to see the exact error. Some monitors only accept DDC/CI on certain inputs or cables. Power-cycling the monitor can help.
• "Failed to set input source": the input may not exist on that monitor. Check list, or try the raw hex code.
• Wrong current input shown: some monitor firmware reports non-standard values even though switching still works.

For a GUI, try NirSoft's ControlMyMonitor.

Why Windows only?

Linux already has ddcutil. ddcswitch fills the same niche on Windows as a standalone native executable.

License

MIT. See LICENSE. Provided as-is, without warranty: DDC/CI commands change monitor settings, so use at your own risk.

Built with Spectre.Console. Inspired by ddcutil.