Training data and recipe
SFT uses examples from
TimeLens2-93K,
TimeLens-100K, and the official Ego4D-NLQ-v2 training split. Training retains
full-video context and supervises variable-cardinality temporal interval sets.
The model sees diverse grounding instructions and timestamp response formats.
The 2B SFT recipe trains for one epoch with packed sequences up to 160K tokens,
a global batch size of 128, and a learning rate of 1e-5. The visual encoder is
frozen during training.
Intended use
- Generate off-policy rollouts for the TimeLens2 GRPO stage.
- Reproduce or extend the SFT-to-GRPO training pipeline.
- Study long-context video temporal grounding before reinforcement learning.
This is an SFT checkpoint. It is not the final GRPO-optimized release reported
in the TimeLens2 paper.
Loading the checkpoint
This checkpoint is hosted in a Hugging Face dataset repository. Download it
locally, then load the directory with Transformers:
from huggingface_hub import snapshot_download
from transformers import AutoModelForImageTextToText, AutoProcessor
model_dir = snapshot_download(
repo_id="MCG-NJU/TimeLens2-2B-SFT",
repo_type="dataset",
)
model = AutoModelForImageTextToText.from_pretrained(
model_dir,
torch_dtype="auto",
device_map="auto",
)
processor = AutoProcessor.from_pretrained(model_dir)
See the official repository for the
SFT and GRPO training recipes, data annotations, rollout configuration, and
evaluation code.
Citation
@misc{zhu2026timelens2,
title={TimeLens2: Generalist Video Temporal Grounding with Multimodal LLMs},
author={Yuhan Zhu and Changlian Ma and Xiangyu Zeng and Xinhao Li and Zhiqiu Zhang and Songze Li and Jun Zhang and Tianxiang Jiang and Yuandong Yang and Ziang Yan and Zikang Wang and Xinyu Chen and Haoran Chen and Shaowei Zhang and Limin Wang},
year={2026},
eprint={2607.17423},
archivePrefix={arXiv},
primaryClass={cs.CV},
url={https://arxiv.org/abs/2607.17423},
}