What's the in_channels's role?

[Dev-ori]

Hi,

In the pytorch_i3d.py file, why the 'in_channels = ' is 384+384+128+128 ?
I wonder what's the meaning of each of numbers (384, 384, 128,128)
and what's difference with "in_channels= 3"

self.logits = Unit3D(in_channels=384+384+128+128, output_channels=self._num_classes,
kernel_shape=[1, 1, 1],
padding=0,
activation_fn=None, #F.sigmoid, # was none changed to Sigmoid
use_batch_norm=False,
use_bias=True,
name='logits')

model = InceptionI3d**(in_channels=3)**