@article{hprohierarchicalprogressiverewardoptimiz,
  title = {HPRO: Hierarchical Progressive Reward Optimization via Preference Extraction for Emotional Text-to-Speech},
  author = {Sihang Nie and Xiaofen Xing and Rui Xing and Haoming Li and Ruitong Xiao and Jingyuan Xing and Baiji Liu and Xiangmin Xu},
  year = {2026},
  eprint = {2606.28249},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2606.28249},
}