Solved by ptrblck in post #4 
              
              
                Here is a small dummy example using multiple video folders. 
Note that I’ve used tensors directly, so you should add your frame loading logic into the Dataset. 
class MyDataset(Dataset):
    def __init__(self, videos, transform=None, nb_frames=3):
        self.nb_frames = nb_frames
        self.tran…