  Training data for video segmentation are expensive to annotate. This impedes
extensions of end-to-end algorithms to new video segmentation tasks, especially
in large-vocabulary settings. To 'track anything' without training on video
data for every individual task, we develop a decoupled video segmentation
approach (DEVA), composed of task-specific image-level segmentation and
class/task-agnostic bi-directional temporal propagation. Due to this design, we
only need an image-level model for the target task (which is cheaper to train)
and a universal temporal propagation model which is trained once and
generalizes across tasks. To effectively combine these two modules, we use
bi-directional propagation for (semi-)online fusion of segmentation hypotheses
from different frames to generate a coherent segmentation. We show that this
decoupled formulation compares favorably to end-to-end approaches in several
data-scarce tasks including large-vocabulary video panoptic segmentation,
open-world video segmentation, referring video segmentation, and unsupervised
video object segmentation. Code is available at:
https://hkchengrex.github.io/Tracking-Anything-with-DEVA
