DB
+-- UCF101
| +-- videos (avi)
| +-- frames (jpeg)
| +-- labels
| +-- custom
| +-- categorical (csv) -> for classification task
| +-- train.csv (default split number is 1 for UCF101 and HMDB51, version 3 for ActivityNet)
| +-- test.csv
| +-- fewshot (csv) -> for few-shot task
| +-- train.csv (default split rate 71:30[train:test] for UCF101)
| (default split rate 36:15[train:test] for HMDB51)
| (default split rate 140:60[train:test] for ActivityNet)
| +-- test.csv
| +-- sampled (json)
| +-- train.json (default split number is 1 for UCF101 and HMDB51, version 3 for ActivityNet)
| ({sub-directory path: {label: label number, category: category name, index: sampeld frame index list}})
| +-- test.json
| +-- official
+-- HMDB51
| +-- same above UCF101
+-- ActivityNet
+-- same above UCF101