Title: MUSEG: Reinforcing Video Temporal Understanding via Timestamp-Aware Multi-Segment Grounding
Primary area: applications to computer vision, audio, language, and other modalities
Keywords: Video Temporal Understanding, Temporal Video Grounding, Reinforcement Learning

Abstract: Video temporal understanding is crucial for multimodal large language models (MLLMs) to reason over events in videos. Despite recent advances in general video understanding, current MLLMs still struggle with fine-grained temporal reasoning. While reinforcement learning (RL) has been explored to address this issue recently, existing RL approaches remain limited in performance on time-sensitive tasks. In this work, we propose **MUSEG**, a novel RL-based method that enhances temporal understanding by introducing timestamp-aware multi-segment grounding. MUSEG enables MLLMs to align queries with multiple relevant video segments, promoting more comprehensive temporal reasoning. To facilitate effective learning, we design a customized RL training recipe with phased rewards that progressively guides the model toward temporally grounded reasoning. Extensive experiments on temporal grounding and time-sensitive video question answering (QA) tasks demonstrate that \methodname significantly outperforms existing methods and generalizes well across diverse temporal understanding scenarios.

TL;DR: We propose MUSEG, a novel RL-based framework that enhances temporal understanding by introducing timestamp-aware multi-segment grounding.