  This is our 2nd-place solution for the ECCV 2022 Multiple People Tracking in
Group Dance Challenge. Our method mainly includes two steps: online short-term
tracking using our Cascaded Buffer-IoU (C-BIoU) Tracker, and, offline long-term
tracking using appearance feature and hierarchical clustering. Our C-BIoU
tracker adds buffers to expand the matching space of detections and tracks,
which mitigates the effect of irregular motions in two aspects: one is to
directly match identical but non-overlapping detections and tracks in adjacent
frames, and the other is to compensate for the motion estimation bias in the
matching space. In addition, to reduce the risk of overexpansion of the
matching space, cascaded matching is employed: first matching alive tracks and
detections with a small buffer, and then matching unmatched tracks and
detections with a large buffer. After using our C-BIoU for online tracking, we
applied the offline refinement introduced by ReMOTS.
