Video-Holmes: Can MLLM Think Like Holmes for Complex Video Reasoning?
Authors: name: Junhao Cheng, name: Yuying Ge, name: Teng Wang, name: Yixiao Ge, name: Jing Liao, name: Ying Shan

Recent advances in CoT reasoning and RL post-training have been reported to
enhance video reasoning capabilities of MLLMs. This progress naturally raises a
question: can these models perform complex video reasoning in a manner
comparable to human experts? However, existing video benchmarks primarily
evaluate visual perception and grounding abilities, with questions that can be
answered based on explicit prompts or isolated visual cues. Such benchmarks do
not fully capture the intricacies of real-world reasoning, where humans must
actively search for, integrate, and analyze multiple clues before reaching a
conclusion. To address this issue, we present Video-Holmes, a benchmark
inspired by the reasoning process of Sherlock Holmes, designed to evaluate the
complex video reasoning capabilities of MLLMs. Video-Holmes consists of 1,837
questions derived from 270 manually annotated suspense short films, which spans
seven carefully designed tasks. Each task is constructed by first identifying
key events and causal relationships within films, and then designing questions
that require models to actively locate and connect multiple relevant visual
clues scattered across different video segments. Our comprehensive evaluation
of state-of-the-art MLLMs reveals that, while these models generally excel at
visual perception, they encounter substantial difficulties with integrating
information and often miss critical clues. For example, the best-performing
model, Gemini-2.5-Pro, achieves an accuracy of only 45%, with most models
scoring below 40%. We aim that Video-Holmes can serve as a "Holmes-test" for
multimodal reasoning, motivating models to reason more like humans and
emphasizing the ongoing challenges in this field. The benchmark is released in
https://github.com/TencentARC/Video-Holmes.