MIDIfiler

MIDIfiler is a software and hardware solution designed to filter, route, and transform MIDI data streams. It is used to selectively pass, modify, or log MIDI messages from keyboards, controllers, and interfaces, enabling complex setups with reduced clutter and increased control.

Key features include rule-based filtering, event routing, and on-the-fly transformation. Users can define filter rules to allow or suppress Note On/Off events, CC messages, program changes, and SysEx based on source, channel, note range, or velocity. Transformations may transpose notes, remap controllers, scale velocity, or re-time messages. The tool can record session data and export filtered streams for analysis.

Architecture and deployment: MIDIfiler can run as standalone hardware device or as software integrated into a DAW or as a modular plugin. It supports common MIDI interfaces and connection methods including USB-MIDI and MIDI over IP. The software offers a user interface for building rules, as well as scripting options in some versions.

Applications: used in live performances to isolate meaningful events, in studios to clean up MIDI tracks, and in research to study MIDI event patterns.

Variants and community: Several implementations exist, ranging from open-source projects to commercial products. Adoption is influenced by compatibility with existing MIDI ecosystems and the flexibility of filtering rules.