From Scores to Preferences: Redefining MOS Benchmarking for Speech Quality Reward Modeling

Fuente: arXiv
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Main Authors: Cao, Yifei, Jiang, Changhao, Zhuang, Jiabao, Sun, Jiajun, Zhang, Ming, Xi, Zhiheng, Li, Hui, Dou, Shihan, Wang, Yuran, Zhang, Yunke, Ji, Tao, Gui, Tao, Zhang, Qi, Huang, Xuanjing
Format: Preprint
Published: 2025
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author Cao, Yifei
Jiang, Changhao
Zhuang, Jiabao
Sun, Jiajun
Zhang, Ming
Xi, Zhiheng
Li, Hui
Dou, Shihan
Wang, Yuran
Zhang, Yunke
Ji, Tao
Gui, Tao
Zhang, Qi
Huang, Xuanjing
author_facet Cao, Yifei
Jiang, Changhao
Zhuang, Jiabao
Sun, Jiajun
Zhang, Ming
Xi, Zhiheng
Li, Hui
Dou, Shihan
Wang, Yuran
Zhang, Yunke
Ji, Tao
Gui, Tao
Zhang, Qi
Huang, Xuanjing
contents Assessing the perceptual quality of synthetic speech is crucial for guiding the development and refinement of speech generation models. However, it has traditionally relied on human subjective ratings such as the Mean Opinion Score (MOS), which depend on manual annotations and often suffer from inconsistent rating standards and poor reproducibility. To address these limitations, we introduce MOS-RMBench, a unified benchmark that reformulates diverse MOS datasets into a preference-comparison setting, enabling rigorous evaluation across different datasets. Building on MOS-RMBench, we systematically construct and evaluate three paradigms for reward modeling: scalar reward models, semi-scalar reward models, and generative reward models (GRMs). Our experiments reveal three key findings: (1) scalar models achieve the strongest overall performance, consistently exceeding 74% accuracy; (2) most models perform considerably worse on synthetic speech than on human speech; and (3) all models struggle on pairs with very small MOS differences. To improve performance on these challenging pairs, we propose a MOS-aware GRM that incorporates an MOS-difference-based reward function, enabling the model to adaptively scale rewards according to the difficulty of each sample pair. Experimental results show that the MOS-aware GRM significantly improves fine-grained quality discrimination and narrows the gap with scalar models on the most challenging cases. We hope this work will establish both a benchmark and a methodological framework to foster more rigorous and scalable research in automatic speech quality assessment.
format Preprint
id arxiv_https___arxiv_org_abs_2510_00743
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle From Scores to Preferences: Redefining MOS Benchmarking for Speech Quality Reward Modeling
Cao, Yifei
Jiang, Changhao
Zhuang, Jiabao
Sun, Jiajun
Zhang, Ming
Xi, Zhiheng
Li, Hui
Dou, Shihan
Wang, Yuran
Zhang, Yunke
Ji, Tao
Gui, Tao
Zhang, Qi
Huang, Xuanjing
Sound
Artificial Intelligence
Computation and Language
Audio and Speech Processing
Assessing the perceptual quality of synthetic speech is crucial for guiding the development and refinement of speech generation models. However, it has traditionally relied on human subjective ratings such as the Mean Opinion Score (MOS), which depend on manual annotations and often suffer from inconsistent rating standards and poor reproducibility. To address these limitations, we introduce MOS-RMBench, a unified benchmark that reformulates diverse MOS datasets into a preference-comparison setting, enabling rigorous evaluation across different datasets. Building on MOS-RMBench, we systematically construct and evaluate three paradigms for reward modeling: scalar reward models, semi-scalar reward models, and generative reward models (GRMs). Our experiments reveal three key findings: (1) scalar models achieve the strongest overall performance, consistently exceeding 74% accuracy; (2) most models perform considerably worse on synthetic speech than on human speech; and (3) all models struggle on pairs with very small MOS differences. To improve performance on these challenging pairs, we propose a MOS-aware GRM that incorporates an MOS-difference-based reward function, enabling the model to adaptively scale rewards according to the difficulty of each sample pair. Experimental results show that the MOS-aware GRM significantly improves fine-grained quality discrimination and narrows the gap with scalar models on the most challenging cases. We hope this work will establish both a benchmark and a methodological framework to foster more rigorous and scalable research in automatic speech quality assessment.
title From Scores to Preferences: Redefining MOS Benchmarking for Speech Quality Reward Modeling
topic Sound
Artificial Intelligence
Computation and Language
Audio and Speech Processing
url https://arxiv.org/abs/2510.00743