MusicGen-Stem: Multi-stem music generation and edition through autoregressive modeling
Simon Rouard, Robin San Roman, Yossi Adi, Axel Roebel
TL;DR
MusicGen-Stem addresses the need for flexible, stem-level control in music generation by introducing per-stem tokenization with specialized compressors and a multi-stream autoregressive transformer that can generate bass, drums, and other stems in parallel. The approach supports text- and audio-conditioned generation as well as stem editing and stem-by-stem iteration, enabling targeted modifications without full regeneration. Evaluations show competitive text-conditioned generation with prior models and superior stem-editing performance against baselines on internal instrumental data separated via Demucs. The work advances practical music creation by enabling coherent stem edits and iterative composition, though it is currently limited to three stems due to data constraints, with future work focusing on improving bass token quality and richer conditioning for the remaining stems.
Abstract
While most music generation models generate a mixture of stems (in mono or stereo), we propose to train a multi-stem generative model with 3 stems (bass, drums and other) that learn the musical dependencies between them. To do so, we train one specialized compression algorithm per stem to tokenize the music into parallel streams of tokens. Then, we leverage recent improvements in the task of music source separation to train a multi-stream text-to-music language model on a large dataset. Finally, thanks to a particular conditioning method, our model is able to edit bass, drums or other stems on existing or generated songs as well as doing iterative composition (e.g. generating bass on top of existing drums). This gives more flexibility in music generation algorithms and it is to the best of our knowledge the first open-source multi-stem autoregressive music generation model that can perform good quality generation and coherent source editing. Code and model weights will be released and samples are available on https://simonrouard.github.io/musicgenstem/.
