GenCompositor: Generative Video Compositing with Diffusion Transformer
Authors: name: Shuzhou Yang, name: Xiaoyu Li, name: Xiaodong Cun, name: Guangzhi Wang, name: Lingen Li, name: Ying Shan, name: Jian Zhang

Video compositing combines live-action footage to create video production,
serving as a crucial technique in video creation and film production.
Traditional pipelines require intensive labor efforts and expert collaboration,
resulting in lengthy production cycles and high manpower costs. To address this
issue, we automate this process with generative models, called generative video
compositing. This new task strives to adaptively inject identity and motion
information of foreground video to the target video in an interactive manner,
allowing users to customize the size, motion trajectory, and other attributes
of the dynamic elements added in final video. Specifically, we designed a novel
Diffusion Transformer (DiT) pipeline based on its intrinsic properties. To
maintain consistency of the target video before and after editing, we revised a
light-weight DiT-based background preservation branch with masked token
injection. As to inherit dynamic elements from other sources, a DiT fusion
block is proposed using full self-attention, along with a simple yet effective
foreground augmentation for training. Besides, for fusing background and
foreground videos with different layouts based on user control, we developed a
novel position embedding, named Extended Rotary Position Embedding (ERoPE).
Finally, we curated a dataset comprising 61K sets of videos for our new task,
called VideoComp. This data includes complete dynamic elements and high-quality
target videos. Experiments demonstrate that our method effectively realizes
generative video compositing, outperforming existing possible solutions in
fidelity and consistency.