---
pipeline_tag: video-text-to-text
library_name: transformers
tags:
- video-understanding
- long-video
- reasoning
- r1
- multimodal
---

# LongVideo-R1-Qwen3

This repository contains the weights for **LongVideo-R1-Qwen3**, an active, reasoning-equipped multimodal large language model (MLLM) agent designed for efficient long video understanding. 

This model was introduced in the paper [LongVideo-R1: Smart Navigation for Low-cost Long Video Understanding](https://arxiv.org/abs/2602.20913), accepted at CVPR 2026.

## Model Description

LongVideo-R1 addresses the challenge of understanding long videos under low computational budgets. Instead of an exhaustive search across all frames, the agent uses a reasoning module to navigate video context, leveraging high-level visual cues to infer the most informative video clips. 

- **Backbone**: Fine-tuned from **Qwen-3-8B**.
- **Training Paradigm**: Two-stage approach involving Supervised Fine-Tuning (SFT) on 33K high-quality chain-of-thought-with-tool trajectories followed by Reinforcement Learning (RL).
- **Architecture**: The agent initiates traversal from top-level visual summaries and iteratively refines its focus, halting once it has sufficient knowledge to answer the query.

## Links
- **Paper**: [arXiv:2602.20913](https://arxiv.org/abs/2602.20913)
- **Code**: [GitHub - qiujihao19/LongVideo-R1](https://github.com/qiujihao19/LongVideo-R1)
- **Data**: [LongVideo-R1-Data](https://huggingface.co/datasets/ChurchillQAQ/LongVideo-R1-Data)

## Usage

LongVideo-R1 can be deployed using `vLLM` for online testing, supporting tool use and multi-round reasoning.

### 1. Deploy the reasoning model
```bash
# Deploy the reasoning model
MODEL_PATH="ChurchillQAQ/LongVideo-R1-Qwen3"
PORT=25600

vllm serve $MODEL_PATH \
  --tensor-parallel-size 1 \
  --max-model-len 32768 \
  --gpu-memory-utilization 0.85 \
  --host 127.0.0.1 \
  --port $PORT \
  --served-model-name longvideor1 
```

### 2. Run Inference (CLI Demo)
Once the model is served (alongside the required caption and video-QA models as described in the [GitHub README](https://github.com/qiujihao19/LongVideo-R1)), you can use `cli.py`:

```bash
python cli.py \
  --video_path /path/to/video.mp4 \
  --question "What is the man doing in this video?" \
  --reasoning_base_url http://127.0.0.1:25600/v1 \
  --caption_base_url http://127.0.0.1:9081/v1 \
  --videoqa_base_url http://127.0.0.1:9081/v1
```

## Citation

```bibtex
@article{qiu2026longvideo,
  title={LongVideo-R1: Smart Navigation for Low-cost Long Video Understanding},
  author={Qiu, Jihao and Xie, Lingxi and Huo, Xinyue and Tian, Qi and Ye, Qixiang},
  journal={arXiv preprint arXiv:2602.20913},
  year={2026}
}
```