command8-cpp

A native C++ userspace engine for the Digidesign Command|8 control surface on Linux and Windows: a DAW-agnostic core library + bridges for Reaper (OSC) and any Mackie-Control-capable DAW (Bitwig, …). The protocol documentation (docs/PROTOCOL.md), the Linux kernel quirk (quirk/) and the Reaper OSC pattern (reaper/) are all included here.

For Linux there is a snd-usb-audio quirk to expose the hidden MIDI input port — the device's MIDIStreaming input descriptor is malformed, so the standard parser does not create one. The patch is in quirk/; apply it to your kernel tree or wrap it in a DKMS package. (On Windows, Digidesign/Avid's own driver exposes the input.) Everything else (protocol translation, the wake/keepalive handshake, LED/fader/meter/ring/LCD feedback) is ordinary userspace logic: So this engine is a normal compiled program that talks to the device over ALSA (Linux) or RtMidi/WinMM (Windows), giving full access to the surface controls and feedback, but with some buttons (EQ, Dynamics) not reproducing the exact function they have in Pro Tools.

Layout

src/protocol.{hpp,cpp}    native MIDI protocol: decode (input) + encode (feedback)
src/surface.hpp           Surface interface: device discovery, wake + keepalive, events
src/midi_port.hpp         MidiPort interface: raw-bytes duplex port (MCU side)
src/alsa/                 ALSA-seq implementations of both (Linux)
src/rtmidi/               RtMidi implementations of both (Windows)
src/feedback.{hpp,cpp}    normalized (0..1) feedback: faders/meters/rings/LEDs/LCD
src/backend.hpp           Backend interface — host integrations subclass this
src/controller.{hpp,cpp}  wires Surface -> Backend, normalizes events
src/main.cpp              command8-monitor: demo Backend (loopback, no DAW)
src/reaper/               command8-reaper: Reaper OSC bridge (liblo)
src/mackie/               command8-mackie: Mackie Control (MCU) emulation
docs/PROTOCOL.md          protocol reverse-engineering evidence (+ raw captures)
quirk/                    Linux snd-usb-audio quirk patch (exposes the MIDI input)
reaper/Command8.ReaperOSC Reaper OSC pattern file for command8-reaper

libcommand8 is DAW-agnostic. A Backend receives normalized input (on_fader(strip, 0..1), on_encoder(strip, ±1), on_select, …) and drives a Feedback handle (meter, ring_dot, select_led, lcd_channel, …) that hides the device bit-packing. Host integrations (a Reaper OSC bridge, a Mackie/HUI translator, a Bitwig backend, …) are Backends built on top — the demo in main.cpp is one (pure loopback: faders→meters, encoders→pan dot, select/mute/solo→LEDs).

Build (Linux)

Requires a C++17 compiler, CMake ≥ 3.16, and libasound2-dev (plus liblo-dev for the Reaper bridge).

cmake -B build
cmake --build build
ctest --test-dir build                 # protocol decode/encode unit tests
./build/command8-monitor               # loopback demo (needs the device + quirk)
./build/command8-reaper                # Reaper OSC bridge (waits for the device)
./build/command8-mackie                # MCU bridge (needs snd-virmidi)

Reaper setup (both platforms)

In Reaper: Preferences → Control/OSC/web → Add → OSC. Set the pattern config to reaper/Command8.ReaperOSC (installed packages put it in <prefix>/share/command8/), device receives on 8000, sends to 9000 — command8-reaper's defaults.

Install / package

cmake --install build --prefix /usr/local     # binaries + systemd user unit + docs

Or build distributable packages (a .deb and a .tar.gz) with CPack:

cd build && cpack                              # -> command8-<ver>-Linux.deb / .tar.gz
sudo apt install ./command8-*-Linux.deb        # deps (libasound2, liblo) auto-resolved

Either way, command8-reaper's ExecStart is rewritten to the real install prefix (/usr/bin for the .deb, /usr/local/bin for a plain install), and the systemd user unit lands in <prefix>/lib/systemd/user/.

Run command8-reaper as a systemd user service (self-heals on unplug/replug):

systemctl --user daemon-reload
systemctl --user enable --now command8-reaper

(Building from source without installing? Copy systemd/command8-reaper.service.in to ~/.config/systemd/user/command8-reaper.service and set ExecStart to your build/command8-reaper.)

Build (Windows)

Requires Visual Studio 2022+ (MSVC), CMake, and vcpkg (all bundled with a Visual Studio install). Dependencies (RtMidi, liblo) come from the vcpkg manifest automatically:

cmake -S . -B build -G Ninja ^
  -DCMAKE_TOOLCHAIN_FILE=%VCPKG_ROOT%\scripts\buildsystems\vcpkg.cmake ^
  -DVCPKG_TARGET_TRIPLET=x64-windows-static
cmake --build build
ctest --test-dir build
build\command8-monitor.exe --list      # check the Command|8's ports are visible
build\command8-monitor.exe             # loopback demo
build\command8-reaper.exe              # Reaper OSC bridge (identical OSC setup)
build\command8-mackie.exe              # MCU bridge (see below)

(From a plain VS developer prompt, %VCPKG_ROOT% is %VSINSTALLDIR%VC\vcpkg. The static triplet folds RtMidi, liblo and the MSVC runtime into the exes; drop it for a plain dynamic dev build.)

Package a portable ZIP of the self-contained exes (command8-<ver>-win64.zip; unzip anywhere, no vcredist or DLLs needed):

cd build && cpack

The Command|8 needs Digidesign/Avid's own driver on Windows to expose its MIDI input and output (Command|8, plus MIDIIN2/3 for the rear MIDI jacks). If another app (a DAW) holds the port, close it first: WinMM ports are exclusive.

Mackie bridge on Windows

Windows has no app-created virtual MIDI ports, so create a loopback pair once with Windows MIDI Services (or two loopMIDI cables and --mcu-recv/--mcu-send):

midi loopback create --name-a "Command8 MCU A" --name-b "Command8 MCU B"

command8-mackie uses side A by default; point the DAW's Mackie Control input and output at side B. The pair is crossed, so neither end hears its own output.

License

GPL-3.0-or-later.