MireloAI and Kyutai Labs say they have released MuScriptor, an open model for multi-instrument music transcription that takes a finished recording and returns separate MIDI tracks for parts like voice, drums, bass and keys. In their announcement posts on X, the companies say the model works from a full mix rather than isolated stems, and Kyutai calls it "the best open model for multi-instrument transcription to date," which is its claim, not an independent benchmark here.