This little tool controls external displays using DDC/CI on Apple Silicon Macs, including displays connected through USB-C/DisplayPort Alt Mode and supported built-in HDMI ports. Useful to embed in various scripts.
For a much more advanced CLI solution check out BetterDisplay's CLI capabilities.
Warning
Please note that this tool does not support Intel Macs. You can use BetterDisplay for free DDC control on all Macs and all ports.
Note
You need clang from Apple's Command Line Tools (installs automatically if not present).
After download, enter (in Terminal):
makeYou can then run the app by entering:
./m1ddc [options]# Sets contrast to 5 on default display
m1ddc set contrast 5
# Returns current luminance ("brightness") on default display
m1ddc get luminance
# Sets red gain to 90
m1ddc set red 90
# Decreases volume by 10 on default display
m1ddc chg volume -10
# Lists displays
m1ddc display list
# Sets volume to 50 on Display 1
m1ddc display 1 set volume 50
# Sets input to DisplayPort 1 on display with UUID '10ACB8A0-0000-0000-1419-0104A2435078'
m1ddc display 10ACB8A0-0000-0000-1419-0104A2435078 set input 15`
set luminance n - Sets luminance (brightness) to n, between 0 and the maximum value (usually 100).
contrast n - Sets contrast to n, between 0 and the maximum value (usually 100).
(red|green|blue) n - Sets the selected color-channel gain to n, between 0 and the maximum value (usually 100).
volume n - Sets volume to n, between 0 and the maximum value (usually 100).
input n - Sets the input source. Common values:
DisplayPort 1: 15, DisplayPort 2: 16, HDMI 1: 17, HDMI 2: 18, USB-C: 27.
input-alt n - Sets the input source using the alternate VCP code used by some LG displays. Common values:
DisplayPort 1: 208, DisplayPort 2: 209, HDMI 1: 144, HDMI 2: 145, USB-C / DP 3: 210.
mute on|off - Enables or disables mute. You can use 1 for on and 2 for off.
pbp n - Configures PIP/PBP on certain Dell displays (such as the U3421W). Known values:
Off: 0, small window: 33, large window: 34, 50/50 split: 36,
26/74 split: 43, 74/26 split: 44, 2x2: 65.
pbp-input n - Sets the secondary PIP/PBP input on certain Dell displays. Known values:
DisplayPort 1: 15, DisplayPort 2: 16, HDMI 1: 17, HDMI 2: 18,
HDMI 1 + HDMI 2 + DisplayPort 1: 15953.
kvm n - Controls the KVM on certain Dell displays. Known values:
KVM order for USB 1–4: 1728, switch to the next device: 65280.
asus-kvm n - Selects the USB upstream on certain ASUS displays (such as the XG27UCDMG)
when Auto KVM is disabled. Known values:
USB-B: 2, USB-C: 3.
get luminance - Returns the current luminance, if supported by the display.
contrast - Returns the current contrast, if supported by the display.
(red|green|blue) - Returns the current color-channel gain, if supported by the display.
volume - Returns the current volume, if supported by the display.
max luminance - Returns the maximum luminance, if supported by the display (usually 100).
contrast - Returns the maximum contrast, if supported by the display (usually 100).
(red|green|blue) - Returns the maximum color-channel gain, if supported by the display (usually 100).
volume - Returns the maximum volume, if supported by the display (usually 100).
chg luminance n - Changes luminance by n (requires current- and maximum-value reading support).
contrast n - Changes contrast by n (requires current- and maximum-value reading support).
(red|green|blue) n - Changes the selected color-channel gain by n (requires current- and maximum-value reading support).
volume n - Changes volume by n (requires current- and maximum-value reading support).
display list [detailed] - Lists connected displays. With detailed, also prints extended display attributes.
n - Selects a display by its list number (1, 2, etc.).
[method=]<id> - Selects a display using an identifier. The default method is uuid.
Available identification methods:
id: <display_id>
uuid: <system_uuid> (default)
edid: <edid_uuid>
seid: <alphanumeric_serial>:<edid_uuid>
basic: <vendor>:<model>:<serial>
ext: <vendor>:<model>:<serial>:<manufacturer>:<alphanumeric_serial>:<product_name>
full: <vendor>:<model>:<serial>:<manufacturer>:<alphanumeric_serial>:<product_name>:<io_location>
Tip
You can also use 'l', 'v' instead of 'luminance', 'volume' etc.
The following display identification methods are supported, and corresponds to the following strings
| Method | Related display attributes |
|---|---|
id |
<display_id> |
uuid |
<system_uuid> |
edid |
<edid_uuid> |
seid |
<alphnum_serial>:<edid_uuid> |
basic |
<vendor>:<model>:<serial> |
ext |
<vendor>:<model>:<serial>:<manufacturer>:<alphnum_serial>:<product_name> |
full |
<vendor>:<model>:<serial>:<manufacturer>:<alphnum_serial>:<product_name>:<io_location> |
Tip
Corresponding display attributes can be obtained using the display list detailed command
Check out the following hammerspoon script.
This script allows you to control the volume of your external Display' brightness, contrast and volume via DDC (if you use an M1 Mac) using m1ddc and also control your Yamaha AV Receiver through network. The script listens to the standard Apple keyboard media keys and shos the standard macOS Brightness and Volume OSDs via uses showosd :
https://gist.github.com/waydabber/3241fc146cef65131a42ce30e4b6eab7
If you like m1ddc, you'll like BetterDisplay even better!
BetterDisplay's CLI documentation: https://github.com/waydabber/BetterDisplay/wiki/Integration-features,-CLI
If you need a complete Swift implementation for DDC control on Apple Silicon macs, you can take a look at AppleSiliconDDC which is a complete self-contained library I made for BetterDisplay (note: some features and M1 HDMI support is missing from the open source code) and MonitorControl.
If you use Raycast, there are extensions available for both m1ddc and BetterDisplay:
- Display Input Switcher — a GUI for m1ddc. It doesn't yet cover all m1ddc features — contributions are welcome via the GitHub repository or through the Raycast contribution guidelines.
- BetterDisplay — a Raycast extension for interacting with BetterDisplay.
Thanks to @tao-j @alin23, @ybbond
Enjoy!