I’ve skipped through the video and maybe there was some confusion.
Regarding your error ar 2:09:
You are printing some info about max_mus and apply the chunk function on inv_mus.
print(max_mus[0])
print(max_mus.size())

return torch.chunk(inv_mus, 2, dim=1)

After calling this function, you are printing again the shapes of both chunks, which have a weird shape ([58, 2, 80]).
I didn’t follow your code, but it seems you were comparing max_mus with inv_mus.
Could it be you mixed up these tensors?
The split and chunk functions do, what they are supposed to do.
a = torch.randn(56, 80)
b = torch.split(a, 40, dim=1)

for split in b:
    print(split.size())
> torch.Size([56, 40])
> torch.Size([56, 40])

c = torch.chunk(a, 2, dim=1)
for chunk in c:
    print(chunk.size())
> torch.Size([56, 40])
> torch.Size([56, 40])