The Opcode Studio 4 is a 128 channel, 8-IN/8-OUT MIDI interface/SMPTE synchronizer. As an interface, the Studio 4 allows the Macintosh to independently communicate with each of the 8 MIDI INs and OUTs. As a synchronizer, it reads and writes SMPTE in all formats. Opcode's Open Music System (OMS) software adds filtering, channelization, note range splitting, controller mapping, and velocity and control value modification to the Studio 4's capabilities.