Glossary

Quick reference for MIDI and application-specific terminology.

MIDI Concepts

CC (Control Change)

A MIDI message that conveys continuous control data (e.g., volume, expression). Each CC has a number (0–127) and a value (0–127). Often called “continuous controllers.”

Note On / Note Off

MIDI messages that represent playing a note. Note On includes note number (pitch) and velocity. Note Off indicates when the note is released.

Program Change (PC)

A MIDI message that selects a program or preset on a connected device. Values 0–127 represent different programs.

NRPN (Non-Registered Parameter Number)

A higher-resolution MIDI message for controlling parameters beyond standard CCs. Uses four bytes: NRPN MSB, NRPN LSB, Data MSB, Data LSB. Allows 16,384+ unique parameter addresses.

RPN (Registered Parameter Number)

Similar to NRPN but standardized. Examples include Pitch Bend Sensitivity (RPN 0) and fine/coarse tuning.

Pitch Bend

A continuous MIDI message for pitch shifting. Range: -8192 to +8191 (center = 0).

Aftertouch

MIDI messages sent after a key is pressed. Two types:

• Channel Aftertouch — Single value for entire keyboard
• Polyphonic Aftertouch — Individual value per note

MIDI Clock (Timing Clock)

Timing signal sent 24 times per quarter note, used to synchronize tempo across devices.

SPP (Song Position Pointer)

A MIDI message indicating playback position in a sequence. Sent 2 times per quarter note.

14-bit CC Resolution

Combining two standard 7-bit CCs (MSB and LSB) to achieve finer control. Allows 0–16,383 resolution instead of 0–127.

Sysex (System Exclusive)

Manufacturer-specific MIDI messages for device control. Format varies by manufacturer.

Application Concepts

Preset

A named collection of:

• Routing rules (Routes)
• Input port settings
• User controls (sliders, dropdowns)

Presets can be activated by mouse click, MIDI event, or program change.

Route

A processing pipeline for MIDI data. Contains one or more Chains, each with a sequence of Filters. Routes define how input MIDI is transformed and where it’s sent.

Chain

A linear sequence of filters within a route. MIDI flows through each filter in order.

Filter

A single transformation or routing rule. Examples:

• Route to MIDI destination
• Transform CC values
• Send to remote server
• Schedule for delayed playback

EasyConfig

Simplified UI for creating basic routes without writing filter definitions. Generates a full Route behind the scenes. Great for learning.

User Control

On-screen interactive element (slider, dropdown) that sends MIDI commands when manipulated. Associated with a specific preset.

Virtual MIDI Port

Software-based MIDI port created by the application (no physical hardware). Allows internal routing between software. Not supported on Windows 11 with MIDI 2.0.

Monitoring

Real-time inspection of incoming MIDI messages. Translates complex formats (NRPN, 14-bit CC) into human-readable labels.

Port Settings

Configuration for how a physical/virtual input port handles MIDI:

• Which message types to ignore
• How to handle MIDI clock
• 14-bit CC translation
• Others

Configuration File

JSON file storing the entire application state:

• All presets
• All routes
• User control definitions
• Connection bookmarks

Located in the server folder, accessible from the Login tab.

Headless Mode

Running the application without a GUI. Useful for server deployments or scripting. Activated via CLI flags.

Connection Bookmark

Saved connection profile for connecting to remote servers. Stores IP address and port.

Common Abbreviations