Hi I try to develop CNN and im not sure how to determine  out_channels for conv2d:
torch.nn.Conv2d(in_channels, out_channel, kernel,stride,Padding)

I know in_channel depend on you use colour or Gray scale, kernel, stride and padding is try and error but how does out_channel come from ? is it just guess? for example
self.conv1 = ConvBlock(3, 64, 3, 2, 1)
how does 64 come from