We propose VidStyleODE, a spatiotemporally continuous disentangled
Video representation based upon StyleGAN and Neural-ODEs.
Effective traversal of the latent space learned by Generative Adversarial Networks (GANs)
has been the basis for recent breakthroughs in image editing. However, the applicability of
such advancements to the video domain has been hindered by the difficulty of representing
and controlling videos in the latent space of GANs. In particular, videos are composed of
content (i.e., appearance) and complex motion components that require a special mechanism to
disentangle and control. To achieve this, VidStyleODE encodes the video content in a
pre-trained StyleGAN \(\mathcal{W}_+\) space and benefits from a latent ODE component to
summarize the spatiotemporal dynamics of the input video. Our novel continuous video
generation process then combines the two to generate high-quality and temporally consistent
videos with varying frame rates. We show that our proposed method enables a variety of
applications on real videos: text-guided appearance manipulation, motion manipulation, image
animation, and video interpolation and extrapolation.

We encode video dynamics and process them using a ConvGRU layer to obtain a dynamic latent
representation \(\mathbf{Z}_{d0}\) used to initialize a latent ODE of the motion (bottom).
We also
encode the video in \(\mathcal{W}_+\) space to obtain a global latent code \(\mathbf{Z}_C\)
(middle). We
combine
the two with an external style cue through an attention mechanism to condition the AdaIN
layer that predicts the directions to the latent codes of the frames in the target video
(top). Modules in \(\textcolor{gray}{\textbf{gray}}\) are \(\it{\textit{pre-trained}}\) and
\(\it{frozen}\)
during training.

We obtain the video global code from the given single frame and use the motion
from another
driving video by extracting its dynamic latent representation.

Comparison to Baselines

2. Text-Guided Appearance Manipulation

We manipulate a source video by specifying a direction based on a given source
text that
describes the video and alternative target descriptions.

Comparison to Baselines

3. Local Dynamic Editing

The rich dynamic representation learned by VidStyleODE, we are able to manipulate the motion
of local body parts of a target video by blending its dynamic representation with another
video.
\[
\mathbf{z}_{d_{new}} = m * \mathbf{z}_{d_1} + (1 - m) * \mathbf{z}_{d_2}
\]
\[
m \in \{0, 1\} ^ {\{ 8 \times 6\}}
\]

4. Temporal Interpolation and Extrapolation

We extract the dynamic representation from \(K\) given frames of timestamps \(
[t_1, t_2, \dots, t_k ]\) and perform interpolation or extrapolation by solving the latent
ODE
in the intended timestamps.

5. Video Dynamic Latent Interpolation

To show the expressiveness of our learned motion representation, we interpolate between two
different dynamic representations by taking a weighted average of
the two and generating a new video accordingly.
\[
\mathbf{z}_{d_{new}} = (1-\lambda) * \mathbf{z}_{d_1} + \lambda * \mathbf{z}_{d_2}
\]

6. Ablation Study On Model Architecture

To demonstrate the effectiveness of the loss and architecture choices of VidStyleODE, we
report sample
generated videos of our method without its most essential components: consistency loss
\(\mathcal{L}_C\), structure loss \(\mathcal{L}_S\),
appearance loss \( \mathcal{L}_A\), latent directions, and the conditional modulation
network.

7. Failure Cases

BibTeX

@misc{vidstyleode,
title={VidStyleODE: Disentangled Video Editing via StyleGAN and NeuralODEs},
author={Moayed Haji Ali and Andrew Bond and Tolga Birdal and Duygu Ceylan and Levent Karacan and Erkut Erdem and Aykut Erdem},
year={2023},
eprint={2304.06020},
archivePrefix={arXiv},
primaryClass={cs.CV}}

Contact

For any questions, please contact Moayed Haji Ali at mali18@ku.edu.tr.