Yes, it seems you are right and don’t need to wrap this Dataset into a DataLoader.
While the num_workers argument is shown in the docs, it’s unfortunately not explained in the parameters.
Inside the Kinetics400 dataset, a VideoClips object will be created, which accepts the num_workers argument as seen here.
Internally a DataLoader is created using the num_workers argument as seen here.
So it seems this “Dataset” reverts the logic of passing a Dataset instance into a DataLoader and uses a DataLoader instead internally.
I’m not sure, if this approach is used for all video datasets.