CaReBench: A Fine-grained Benchmark for Video Captioning and Retrieval

ICLR 2026 Conference SubmissionAnonymous Authors
Multimodal Large Language ModelFine-grained Video RetrievalVideo Detailed Captioning
Abstract:

Video understanding, including video captioning and retrieval, is still a great challenge for video-language models (VLMs). The existing video retrieval and caption benchmarks only include short descriptions, limits their ability of detailed video understanding evaluation. To address this problem, we present CaReBench, a testing benchmark for fine-grained video Captioning and Retrieval with 1,000 high-quality pairs of videos and human-annotated detailed captions. Uniquely, it provides manually separated spatial annotations and temporal annotations for each video. Based on this design, we introduce two evaluation metrics, ReBias and CapST, specifically tailored for video retrieval and video captioning tasks, respectively. These metrics enable a comprehensive investigation into the spatial and temporal biases inherent in VLMs. In addition, to handle both video retrieval and video captioning tasks in a unified framework, we develop a simple baseline based on a Multimodal Language Model (MLLM). By implementing a two-stage Supervised Fine-Tuning (SFT), we fully unlock the potential of MLLM, enabling it not only to generate detailed video descriptions but also to extract video features. Surprisingly, experimental results demonstrate that, compared to the CLIP-based models designed for retrieval and the popular MLLMs skilled in video captioning, our baseline shows competitive performance in both fine-grained video retrieval and video detailed captioning.

Disclaimer
This report is AI-GENERATED using Large Language Models and WisPaper (A scholar search engine). It analyzes academic papers' tasks and contributions against retrieved prior work. While this system identifies POTENTIAL overlaps and novel directions, ITS COVERAGE IS NOT EXHAUSTIVE AND JUDGMENTS ARE APPROXIMATE. These results are intended to assist human reviewers and SHOULD NOT be relied upon as a definitive verdict on novelty.
NOTE that some papers exist in multiple, slightly different versions (e.g., with different titles or URLs). The system may retrieve several versions of the same underlying work. The current automated pipeline does not reliably align or distinguish these cases, so human reviewers will need to disambiguate them manually.
If you have any questions, please contact: mingzhang23@m.fudan.edu.cn

Overview

Overall Novelty Assessment

The paper introduces CaReBench, a benchmark for fine-grained video captioning and retrieval with 1,000 video-caption pairs featuring manually separated spatial and temporal annotations. It resides in the 'Fine-Grained Captioning and Retrieval Benchmarks' leaf, which contains six papers total. This leaf sits within the broader 'Evaluation Benchmarks and Datasets' branch, indicating a moderately populated research direction focused on rigorous assessment protocols. The sibling papers include TemporalBench, VCapsBench, and domain-specific benchmarks, suggesting an active but not overcrowded space where specialized evaluation resources are emerging to address limitations in coarse-grained metrics.

The taxonomy reveals neighboring leaves addressing dense annotations, general evaluation campaigns, and text-to-video generation datasets. CaReBench's emphasis on dual-task evaluation (captioning and retrieval) with explicit spatial-temporal decomposition distinguishes it from siblings that may focus on temporal reasoning alone or single-task assessment. The broader 'Evaluation Benchmarks and Datasets' branch excludes methods and models, clarifying that this work contributes infrastructure rather than algorithmic innovation. Its position reflects a field trend toward fine-grained, multi-faceted evaluation that complements advances in captioning methods and multimodal models documented in adjacent taxonomy branches.

Among 30 candidates examined, none clearly refute any of the three contributions: the benchmark itself, the ReBias and CapST metrics, and the CARE unified baseline. Each contribution was assessed against 10 candidates with zero refutable overlaps identified. This suggests that within the limited search scope, the combination of detailed spatial-temporal annotations, bias-aware metrics, and a two-stage fine-tuning approach for dual-task handling appears relatively novel. However, the analysis explicitly covers top-K semantic matches and does not claim exhaustive coverage of all prior benchmarks or evaluation methodologies in video understanding.

Based on the limited literature search, the work appears to occupy a distinct niche by integrating fine-grained annotation design with task-specific metrics and a unified modeling framework. The absence of refutable candidates among 30 examined papers indicates no immediate prior work providing the same combination of features, though the search scope leaves open the possibility of related efforts in broader or less semantically similar contexts. The taxonomy structure confirms that fine-grained evaluation is an active area, but CaReBench's specific design choices—manual spatial-temporal separation and dual-task metrics—are not directly replicated in the identified sibling benchmarks.

Taxonomy

Core-task Taxonomy Papers
50
3
Claimed Contributions
30
Contribution Candidate Papers Compared
0
Refutable Paper

Research Landscape Overview

Core task: Fine-grained video captioning and retrieval evaluation. The field has evolved around several interconnected branches that address different facets of understanding and describing video content at a detailed level. Fine-grained video captioning methods focus on generating rich, temporally aware descriptions that capture nuanced actions and events, often leveraging hierarchical or graph-based representations to model complex scene dynamics. Video-text retrieval methods emphasize aligning visual and linguistic modalities for precise matching, exploring cross-modal embeddings and attention mechanisms to bridge the semantic gap. Evaluation benchmarks and datasets provide the critical infrastructure for measuring progress, offering diverse testbeds that range from general-purpose collections to specialized domains such as sports narratives or human motion. Multimodal video understanding models integrate large-scale vision-language pretraining with architectural innovations, while survey and review papers synthesize methodological trends and highlight open challenges across captioning, retrieval, and evaluation paradigms. Recent work has intensified efforts to develop more rigorous evaluation protocols that move beyond coarse-grained metrics, addressing the need for fine-grained temporal and semantic assessment. CaReBench[0] exemplifies this direction by proposing a comprehensive benchmark specifically designed to evaluate both captioning quality and retrieval accuracy with fine-grained criteria, situating itself alongside other specialized benchmarks like TemporalBench[9] and VCapsBench[31] that probe temporal reasoning and detailed visual understanding. Compared to broader evaluation frameworks such as Verified[13] or domain-specific testbeds like Fine-grained Retrieval Benchmark[32], CaReBench[0] emphasizes the dual challenge of generating and retrieving precise descriptions, reflecting a growing recognition that evaluation must capture subtle distinctions in video content. This focus on fine-grained assessment complements methodological advances in quality-aware feedback mechanisms and adaptive video-language modeling, underscoring ongoing efforts to align evaluation practices with the increasing sophistication of multimodal video understanding systems.

Claimed Contributions

CaReBench: A fine-grained benchmark for video captioning and retrieval

The authors introduce CaReBench, a new benchmark containing 1,000 videos with human-annotated detailed captions. Each video includes hierarchical descriptions covering overall summary, static objects, dynamic actions, and miscellaneous aspects, with manually separated spatial and temporal annotations to enable comprehensive evaluation of video-language models.

10 retrieved papers
ReBias and CapST evaluation metrics

The authors develop two novel evaluation metrics designed for their benchmark: ReBias for video retrieval and CapST for video captioning. These metrics enable comprehensive investigation of spatial and temporal biases in video-language models by leveraging the manually separated spatial and temporal annotations.

10 retrieved papers
CARE: A unified baseline for video retrieval and captioning

The authors present CARE, a unified baseline model built on multimodal language models that handles both video retrieval and captioning tasks. Through two-stage supervised fine-tuning, the model can generate detailed video descriptions and extract video features, achieving competitive performance on both tasks compared to specialized models.

10 retrieved papers

Core Task Comparisons

Comparisons with papers in the same taxonomy category

Contribution Analysis

Detailed comparisons for each claimed contribution

Contribution

CaReBench: A fine-grained benchmark for video captioning and retrieval

The authors introduce CaReBench, a new benchmark containing 1,000 videos with human-annotated detailed captions. Each video includes hierarchical descriptions covering overall summary, static objects, dynamic actions, and miscellaneous aspects, with manually separated spatial and temporal annotations to enable comprehensive evaluation of video-language models.

Contribution

ReBias and CapST evaluation metrics

The authors develop two novel evaluation metrics designed for their benchmark: ReBias for video retrieval and CapST for video captioning. These metrics enable comprehensive investigation of spatial and temporal biases in video-language models by leveraging the manually separated spatial and temporal annotations.

Contribution

CARE: A unified baseline for video retrieval and captioning

The authors present CARE, a unified baseline model built on multimodal language models that handles both video retrieval and captioning tasks. Through two-stage supervised fine-tuning, the model can generate detailed video descriptions and extract video features, achieving competitive performance on both tasks compared to specialized models.