Data Preparation

The pre-processing of Something-Something-V2 follows VideoMAE, which can be summarized into 3 steps:
1. Download the dataset from official website.
2. Preprocess the dataset by changing the video extension from webm to .mp4 with the original height of 240px.. You can simply run ffmpeg -i [input.webm] -c:v libx264 [output.mp4].
3. Generate annotations needed for dataloader ("<path_to_video> <video_class>" in annotations). The annotation usually includes train.csv, val.csv and test.csv ( here test.csv is the same as val.csv). The format of *.csv file is like:
```
dataset_root/video_1.mp4  label_1
dataset_root/video_2.mp4  label_2
dataset_root/video_3.mp4  label_3
...
dataset_root/video_N.mp4  label_N
```