boxes annotation

[yan-ctrl]

Hello, I want to apply your work to my own dataset. I would like to ask you how boxes annotation is obtained from the dataset.that is, a few files， Is it key frame detection? I look forward to your reply?
AVA/
|_ boxes/
| |_ ava_val_det_person_bbox.json
| |_ ava_train_det_object_bbox.json
| |_ ava_val_det_object_bbox.json

[yan-ctrl]

I want to use your work for my own data set. Can you tell me how the annotations of boxes came about? Looking forward to your reply