The emergence of diffusion models has greatly propelled the progress
in image and video generation. Recently, some efforts have been
made in controllable video generation, including text-to-video,
image-to-video generation, video editing, and video motion control,
among which camera motion control is an important topic. How-
ever, existing camera motion control methods rely on training a
temporal camera module, and necessitate substantial computation
resources due to the large amount of parameters in video genera-
tion models. Moreover, existing methods pre-define camera motion
types during training, which limits their flexibility in camera con-
trol, preventing the realization of some specific camera controls,
such as various camera movements in films. Therefore, to reduce
training costs and achieve flexible camera control, we propose
COMD, a novel training-free video motion transfer model, which
disentangles camera motions and object motions in source videos,
and transfers the extracted camera motions to new videos. We first
propose a one-shot camera motion disentanglement method to ex-
tract camera motion from a single source video, which separates
the moving objects from the background and estimates the camera
motion in the moving objects region based on the motion in the
background by solving a Poisson equation. Furthermore, we pro-
pose a few-shot camera motion disentanglement method to extract
the common camera motion from multiple videos with similar cam-
era motions, which employs a window-based clustering technique
to extract the common features in temporal attention maps of mul-
tiple videos. Finally, we propose a motion combination method to
combine different types of camera motions together, enabling our
model a more controllable and flexible camera control. Extensive
experiments demonstrate that our training-free approach can ef-
fectively decouple camera-object motion and apply the decoupled
camera motion to a wide range of controllable video generation
tasks, achieving flexible and diverse camera motion control.
