Omni-RRM: Advancing Omni Reward Modeling via Automatic Rubric-Grounded Preference Synthesis

· Source: cs.CL updates on arXiv.org · Field: Technology & Digital — Artificial Intelligence & Machine Learning, Data Science & Analytics · Depth: Expert, extended

Summary

Omni-RRM is the first open-source rubric-grounded reward model designed to enhance multimodal large language models (MLLMs) by providing structured, multi-dimension preference judgments with justifications across text, image, video, and audio. It addresses limitations of existing vision-centric reward models (RMs) that often return opaque scalar scores and rely on costly human annotations. Omni-RRM is trained on Omni-Preference, a large-scale dataset of approximately 41K preference examples, built via a fully automated pipeline using strong teacher models for rubric-grounded rationales. The model achieves state-of-the-art accuracy on video (80.2% on ShareGPT-V) and audio (66.8% on Audio-HH-RLHF) benchmarks, and a 17.7% absolute gain over its base model on image tasks. It also improves downstream performance via Best-of-$N$ selection and transfers to text-only preference benchmarks.

Key takeaway

For AI Scientists and ML Engineers developing multimodal LLMs, Omni-RRM offers a robust solution for alignment. Its rubric-grounded, multi-dimensional feedback provides clear insights into model errors, surpassing opaque scalar scores. You should consider integrating Omni-RRM to enhance model interpretability, reduce reliance on costly human annotation, and achieve state-of-the-art performance across diverse modalities, including audio and video. This approach can significantly improve the reliability and trustworthiness of your MLLM deployments.

Key insights

Omni-RRM provides structured, rubric-grounded multimodal preference judgments without human annotation.

Principles

Method

Omni-RRM is trained in two stages: Supervised Fine-Tuning (SFT) for rubric-grounded output, then Group Relative Policy Optimization (GRPO) to sharpen discrimination on low-contrast pairs.

In practice

Topics

Best for: Research Scientist, AI Scientist, Machine Learning Engineer, AI Engineer

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Editorial summary, takeaway, and curation by AIssential. Original article published by cs.CL updates on arXiv.org.