This view operations looks wrong:
x = x.view(1, 64000)

since you are flattening the tensor such that it’ll have a batch size of 1.
To keep the batch size equal, use x = x.view(x.size(0), -1) instead.
In case you would still run into the batchnorm issue, check if the last batch returned by the DataLoader might be smaller. If that’s the case you can drop it via drop_last=True.