What is a MIDI filter?

A MIDI filter is a tool or device used to process MIDI data by selectively allowing, modifying, or blocking certain MIDI messages based on predefined criteria. This can include filtering out specific types of messages, such as note on/off, control changes, or program changes, to streamline or customize MIDI performance. MIDI filters are often used in music production and live performances to manage complex MIDI setups, ensuring only relevant data is transmitted to instruments or software.