Control OBS
Filters With
MIDI

Plug your Novation SL Zero MK1 into the Mac Mini via USB. macOS recognises it as a class-compliant MIDI device — no driver install required on Apple Silicon.

Verify the connection

• Open Audio MIDI Setup (Spotlight → "Audio MIDI Setup")
• Go to Window → Show MIDI Studio
• You should see SL MkII or Zero SL MkII appear as a connected device icon
• If not visible, try a different USB port or cable and relaunch Audio MIDI Setup

OBS Studio does not have built-in MIDI support. The best current plugin for macOS is obs-midi-mg (MIDI Mapper for OBS), which supports filter parameter mapping.

Download & install

• Go to github.com/nhielost/obs-midi-mg/releases
• Download the latest .pkg installer for macOS
• Run the installer — it places the plugin into your OBS plugins folder automatically
• Fully quit and relaunch OBS after installation

Confirm the plugin loaded: in OBS go to Tools menu — you should see MIDI-MG Settings listed.

Every fader and knob on the SL Zero MK1 sends a MIDI Control Change (CC) message on a specific channel and CC number. You need to know these before mapping.

Find CC numbers with a MIDI monitor

• Download Protokol (free) from hexler.net/protokol
• Open Protokol, select your SL Zero MK1 as the MIDI input
• Move a fader — note the CC number and Channel shown (e.g. CC 0, Ch 1)
• Turn a knob — note its CC number (e.g. CC 21, Ch 1)
• Write these down — you'll enter them in the plugin

Typical SL Zero MK1 default CC assignments

Make sure you have a video source in your scene with a filter applied. This is what MIDI will control.

Add a filter (if not already done)

• In OBS, right-click your video source in the Sources panel
• Select Filters
• Click the + button under Effect Filters
• Choose a filter — e.g. Color Correction for brightness/contrast/saturation, or Sharpen
• Give it a recognisable name (e.g. "Brightness Control")
• Close the Filters window

This is where you connect your physical fader/knob to the filter parameter in OBS.

Open the plugin

• In OBS, click Tools → MIDI-MG Settings
• In the Devices panel, find and enable your SL Zero MK1
• Click Add Binding (or the + button)

Configure the binding — Fader example

• MIDI In: Select Control Change as message type
• Channel: Set to the channel found in Step 3 (usually 1)
• CC Number: Enter the fader's CC number (e.g. 0 for Fader 1)
• Action: Select Source Filter from the action dropdown
• Source: Choose your video source name from the list
• Filter: Choose the filter you added (e.g. "Brightness Control")
• Parameter: Select the specific slider (e.g. Brightness)
• Value Range: Set min/max to match the filter's range (e.g. −1.0 to 1.0 for Brightness)
• Click Save or Apply

Configure a second binding — Knob example

• Click Add Binding again
• Set CC Number to your knob's number (e.g. 21 for Knob 1)
• Follow the same steps above but choose a different parameter (e.g. Saturation)
• Save

Common filter parameter ranges

With bindings saved, move the fader or knob on the SL Zero — you should see the filter parameter update in real time in OBS.

Testing checklist

• Move your mapped fader — watch the filter slider move in OBS Filters window
• Turn your mapped knob — confirm the second parameter responds
• Check that values don't jump (if they do, adjust the min/max range)
• Preview your scene — confirm the video output visually changes

Common issues & fixes

• No MIDI input detected: Ensure the SL Zero is connected before OBS opens, or restart OBS after plugging in
• Wrong CC triggers the action: Re-check CC numbers in Protokol — move only one control at a time
• Parameter jumps to extreme: Your value range min/max is inverted — swap them in the binding
• Plugin doesn't appear in Tools menu: Check macOS Gatekeeper — go to System Settings → Privacy & Security and allow the plugin
• Filter not listed in plugin: The filter must be added to the source before opening MIDI-MG Settings; close and reopen the plugin dialog