  In this technical report, we represent our solution for the Human-centric
Spatio-Temporal Video Grounding (HC-STVG) track of the 4th Person in Context
(PIC) workshop and challenge. Our solution is built on the basis of TubeDETR
and Mutual Matching Network (MMN). Specifically, TubeDETR exploits a video-text
encoder and a space-time decoder to predict the starting time, the ending time
and the tube of the target person. MMN detects persons in images, links them as
tubes, extracts features of person tubes and the text description, and predicts
the similarities between them to choose the most likely person tube as the
grounding result. Our solution finally finetunes the results by combining the
spatio localization of MMN and with temporal localization of TubeDETR. In the
HC-STVG track of the 4th PIC challenge, our solution achieves the third place.
