Diversity-Rewarded CFG Distillation
Authors: name: Geoffrey Cideron; name: Andrea Agostinelli; name: Johan Ferret; name: Sertan Girgin; name: Romuald Elie; name: Olivier Bachem; name: Sarah Perrin; name: Alexandre Ramé
Published: 2024-10-08 14:40:51

Abstract: Generative models are transforming creative domains such as music generation,
with inference-time strategies like Classifier-Free Guidance (CFG) playing a
crucial role. However, CFG doubles inference cost while limiting originality
and diversity across generated contents. In this paper, we introduce
diversity-rewarded CFG distillation, a novel finetuning procedure that distills
the strengths of CFG while addressing its limitations. Our approach optimises
two training objectives: (1) a distillation objective, encouraging the model
alone (without CFG) to imitate the CFG-augmented predictions, and (2) an RL
objective with a diversity reward, promoting the generation of diverse outputs
for a given prompt. By finetuning, we learn model weights with the ability to
generate high-quality and diverse outputs, without any inference overhead. This
also unlocks the potential of weight-based model merging strategies: by
interpolating between the weights of two models (the first focusing on quality,
the second on diversity), we can control the quality-diversity trade-off at
deployment time, and even further boost performance. We conduct extensive
experiments on the MusicLM (Agostinelli et al., 2023) text-to-music generative
model, where our approach surpasses CFG in terms of quality-diversity Pareto
optimality. According to human evaluators, our finetuned-then-merged model
generates samples with higher quality-diversity than the base model augmented
with CFG. Explore our generations at
https://google-research.github.io/seanet/musiclm/diverse_music/.