Reg-DPO: SFT-Regularized Direct Preference Optimization with GT-Pair for
  Improving Video Generation
Authors: name: Jie Du, name: Xinyu Gong, name: Qingshan Tan, name: Wen Li, name: Yangming Cheng, name: Weitao Wang, name: Chenlu Zhan, name: Suhui Wu, name: Hao Zhang, name: Jun Zhang

Recent studies have identified Direct Preference Optimization (DPO) as an
efficient and reward-free approach to improving video generation quality.
However, existing methods largely follow image-domain paradigms and are mainly
developed on small-scale models (approximately 2B parameters), limiting their
ability to address the unique challenges of video tasks, such as costly data
construction, unstable training, and heavy memory consumption. To overcome
these limitations, we introduce a GT-Pair that automatically builds
high-quality preference pairs by using real videos as positives and
model-generated videos as negatives, eliminating the need for any external
annotation. We further present Reg-DPO, which incorporates the SFT loss as a
regularization term into the DPO objective to enhance training stability and
generation fidelity. Additionally, by combining the FSDP framework with
multiple memory optimization techniques, our approach achieves nearly three
times higher training capacity than using FSDP alone. Extensive experiments on
both I2V and T2V tasks across multiple datasets demonstrate that our method
consistently outperforms existing approaches, delivering superior video
generation quality.